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CLASS 338,	ELECTRICAL RESISTORS
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SECTION I - CLASS DEFINITION

GENERAL STATEMENT OF THE CLASS SUBJECT MATTER:

A. This class includes electrical resistors as above defined with solid, granular, or liquid resistance elements. These resistors may be either fixed or variable in resistance value, examples of the latter being rheostats and potentiometers. Semiconductors are included if limited by claimed subject matter to resistance properties, such as exists in photoconductive and thermistor type resistors. Excluded are conductors and insulators, which while including a resistive characteristic have other predominating characteristics.

B. Included also are resistors with perfecting structure not elsewhere classified such as resistors whose resistance value is temperature compensated, or resistors mounted on wheels or on a vehicle, resistors with heat dissipating projections, or with cooling gas or liquid circulation, or with heat storing, or with inductance or capacity reducing, or with electrical shields, or with a cleaner or a setting indicator in a mechanically variable resistor, or with a casing or housing, or with protecting structure spaced from the element, or with mounting or supporting means.

C. Included also are resistors combined with or incorporated in other structure not elsewhere classifiable, such as resistors with certain diverse nonelectrical devices, for example, mechanical or chemical; or resistors in, on, or with certain electrical devices such as a lamp socket or lamp base, or an electric switch, or a coaxial line or wave guide, or a detachable electrical connector.

D. Included also are resistors constructed as by shape or from material to change their resistance value particularly well in response to a particular condition or change in a particular condition such as current and/or voltage, as for example nonlinear and negative resistors; or ambient temperature; or a magnetic field; or gas, vapor, or moisture; or resistors of the strain gauge or photoconductive type. Included also are resistors usually of the mechanically variable type together with a condition sensing actuator which changes the mechanical adjustment of the resistor in response to a condition or a change in condition. Examples of such actuators are a magnetic compass, a float, a piston, a Bourdon tube, a bellows or capsule, a diaphragm, a gravity stabilized or inertia type actuator, or a force sensing actuator.

E. Subcombinations and components of resistors not otherwise classifiable, such as resistance element cores and frames, resistance elements of particular shape or dimensions, and movable contact structures for variable resistors.

SECTION II - LINES WITH OTHER CLASSES AND WITHIN THIS CLASS

Certain devices, at least quasi-resistive in character, are not classified here. Electric space discharge devices which may exhibit a resistance characteristic between terminals are classified elsewhere. Numerous different types of active solid-state devices, e.g., semiconductor, devices or components whose electrical resistance varies nonlinearly due to the movement of charge carriers - electrons or holes - which undergo energy level changes within the material (as contrasted with the passive or pure resistors found in Class 338) are classified elsewhere. Negative resistors of the active element type are classified elsewhere. Resistors specific to telephone use, including those of the microphone, its electrodes, and granules are classified elsewhere. (See References to Other Classes, below.)

(1) PLURAL RESISTORS AS DEFINED IN THE CLASS DEFINITION

Two or more mechanically or electrically related resistors are classified here as a residual home. For plural photoconductive resistors; plural separate diverse resistors; plural mechanically adjustable resistors; plural incased, embedded, or housed resistors; and for plural supported resistors see Subclass References to the Current Class, below. Regulation systems including a plurality of resistors are classified elsewhere. (See References to Other Classes, below.)

(2) RESISTORS COMBINED WITH OR INCORPORATED IN OTHER DEVICES:

As stated in the Class Definition, E, above, this class includes resistors combined with or incorporated in other structure when not elsewhere classifiable. For resistors with a restricted type of heat reflector; for a resistor with a diverse nonelectrical device, e.g., mechanical or chemical; for resistors in or on a lamp socket or base; for a resistor with a switch; for a resistor in a coaxial line or wave guide; and for a resistor in a detachable electrical connector see Subclass References to the Current Class, below.

The combination of the resistor with or in other structure is very common. A partial list of the classes and subclasses including this combination is given in References To Other Classes, below, referenced to this section.

(3) RESISTANCE COMPONENTS AND SUBCOMBINATIONS:

As stated in the Class Definition, E, above, this class includes subcombinations and components of resistors not otherwise classifiable. For contact structure adapted to move along the length of a resistance element in a mechanically variable resistor and making an electrical connection with the element; resistance element cores and frames; and for resistance elements and bases of particular configuration and/or dimension see Subclass References to the Current Class, below. In References to Other Classes, below, see the references to this section for the classification of the more common subject matter which may constitute a part or subcombination or a resistor.

(4) DEVICES SIMULATING RESISTORS:

Dissipating terminations for long lines; artificial lines; negative resistance networks of the active element type; and for resonators of the distributed parameter type are classified elsewhere. (See References to Other Classes, below.)

(5) METHODS OF AND APPARATUS FOR MAKING RESISTORS:

This class does not provide for methods of making resistors. This subject matter is classified elsewhere, (A) when involving a metal working process; or (B) when involving a metal working process combined with a nonmetal working process, if not otherwise classifiable; or (C) when the process is not otherwise classifiable. See References to Other Classes, below, for a field of search for methods of making resistors. Apparatus for assembling electrical resistors are classified elsewhere. Methods and apparatus for making a resistor coil which is a composite of a core and a winding thereabout are classified elsewhere. (See References to Other Classes, below.)

(6) MEASURING AND TESTING RESISTORS:

This class does not provide for either methods of or apparatus for measuring and testing resistors. If the measuring or testing involves determining the resistance or conductivity of the resistor, classification is elsewhere. If the measuring or testing is of a mechanical nature or not otherwise classified, classification is elsewhere. See elsewhere for a field of search for measuring and testing. (See References to Other Classes, below.)

(7) ELECTRICAL RESISTANCE HEATERS:

Resistors classified in Class 338 in performing their current impeding function produce heat, as do the resistance heaters classified in Class 219, Electric Heating. In the resistors classified in Class 338 the heat produced is incidental or undesired; or is utilized internally only to modify in some manner, as in a thermistor, the temperature of the resistor to in turn modify the current impeding characteristic of the resistor. In the resistance heaters classified in Class 219 the heat produced is put to some external use as opposed to mere dissipation or internal heating of the resistance element. Thus, in general, the resistance heaters in Class 219 include significant structure, shape or arrangement to produce and convert the heat to a useful purpose, as to direct or distribute the heat in a particular manner. The following paragraphs cover the more common situations arising between these two classes.

(A) The mere designation of the claimed structure as a heater or heater element, such a toaster or a blanket, or the broad recitation in the claim of intended use or adaption for heating purposes or for use with structure to be heated is not sufficient for classification in Class 219.

(B) The recitation of the device to be heated in combination with the heating resistor is classified in Class 219 rather than in Class 338. Likewise classification is in Class 219 when the resistor is shaped or otherwise adapted to conform to the structure to be heated to facilitate the transfer of heat to this structure, such shape or adaption not having general utility.

(C) The combination of a resistor and a casing of good heat conducting material is classified in Class 338. For classification in Class 219 as indicated above the heating resistor with its casing must be adapted as by shape to transfer, distribute, or direct the heat in a particular manner or pattern.

(D) Resistors whose elements are formed as fabrics or pads are classified in Class 338. However, if the fabric or pad is shaped or dimensioned to constitute a particular heating device, such as an article of clothing or a blanket classification is in Class 219. Mere fabrics including metal of resistance material, as when the resistance terminals are not claimed is classified elsewhere.

(E) The combination of a resistor and structure to facilitate the external heating effect of the resistor, such as a reflector, is classified in Class 219. Likewise Class 219 includes those resistors which are shaped to produce a desired heating effect or distribution. Resistors including reflectors which direct heat on the resistance element are classified herein (see Subclass References to the Current Class, below).

(F) A few structures such as liquid resistance heaters and liquid cooled resistors, may be considered either resistance heaters for Class 219 or resistors for Class 338. These structures are classified in accordance with the recited use and background.

(8) RESISTANCE FURNACES:

Electric furnaces combined with the heating resistors, as a resistor with the furnace wall; or includes resistors which are formed to constitute at least part of a furnace, as being hollow to form a muffle or being recessed to form a crucible; or includes resistors which are peculiar to an electric furnace, as having the shape of the furnace, such shape having no significance elsewhere are classified elsewhere.

(9) RESISTORS FORMED BY COATING OR LAMINATING:

Processes of forming electrical products when formed by a coating process, per se, and when formed by a laminating step, per se, are classified elsewhere. A plurality of layers of laminated or coated material, one layer being a resistance element and the other layer or layers being terminals, no particular structure being recited, but usually only particular materials, are classified elsewhere, even though the terminals and resistance elements are claimed by such names. See this class (338) for a resistor whose element is coated on a base and for resistors with terminals coated on, together with significant resistance structure such as a particular shape. (See Subclass References to the Current Class and References to Other Classes, below.)

(10) CONDUITS, CABLES, AND CONDUCTORS WITH RESISTIVE MATERIAL:

Conduits, cables, and conductors where the conducting part is a resistor or a helical resistor are classified elsewhere. Such claimed terms as resistance, resistance element, helical resistance, coil resistance, or a terminal at one end of a sheathed resistor do not preclude classification elsewhere. However, when the conducting element in such conduits, cables, or conductors is recited as being of a material which is essentially resistive such as iron, classification is in Class 338. Likewise when significant resistance structure or configuration such as the resistor having a zigzag pattern, or being wound on a core is recited, classification is in Class 338. Conduits, cables or conductors with a nominally resistive or helically resistive element together with end structure and cables whose conducting elements are nominally resistive or helically resistive are classified elsewhere. The claimed combination of a resistor broadly with end structure or terminals at each end is classified in Class 338.

(11) ELECTRICAL CONNECTORS WITH RESISTIVE CONDUCTORS:

The combination of an electrical connector and lead conductor, the lead conductor being nominally claimed as being resistive, is classified elsewhere. If the lead conductor is recited as being of significant resistor structure or material, such as a zigzag shape or of iron material, classification is in Class 338. The combination of a nominally recited resistive conductor with an electrical connector at each end is classified in this class (338) . The inclusion of additional connectors cooperable with the connector or connectors on the resistance element does not preclude classification in Class 338. (See Subclass References to the Current Class and References to Other Classes, below.)

(12) SEMICONDUCTORS:

Semiconductors are classified in Class 338 if possessing only resistance characteristics. Such semiconductors may be photoconductive or may be of the thermistor type (see Subclass References to the Current Class, below). However, if the semiconductor has other more comprehensive characteristics, classification is elsewhere. Numerous different types of active solid-state devices, e.g., semiconductor, devices or components whose electrical resistance varies nonlinearly due to the movement of charge carriers - electrons or holes - which undergo energy level changes within the material (as contrasted with the passive or pure resistors found in Class 338) elsewhere. (See References to Other Classes, below.)

(13) MEASURING AND TESTING DEVICES WITH VARIABLE RESISTORS:

This Class 338 provides generally for resistors which are shaped or chemically constituted to change their resistance value in response to a condition or change in condition, or for mechanically variable resistors combined with a condition sensing actuator. However, when additional structure is claimed for indicating the change in resistance value as a meter for measuring the current passing through the resistance element, or a Wheatstone bridge arrangement including the resistance element as one of the arms, the combination is classified as a measuring or testing device. Distance measuring devices and gauges, namely, a condition responsive resistor and an indicating device or circuit are classified elsewhere; moisture content and stress and strain measuring devices, dynamometers, liquid level or depth gauges, hygrometers, and fluid pressure gauges including this combination are classified elsewhere; a thermometer including this combination is classified elsewhere; and time and/or speed measuring devices including this combination are classified elsewhere. See References to Other Classes, below. See also the reference to Class 338 in References to Other Classes in the Class Definitions of Class 73.

(14) RESISTANCE COMPONENTS AND SUBCOMBINATIONS:

This class (338) provides for resistance components and subcombinations which are not otherwise classifiable. This class (338) includes resistance cores or frames including a base usually of insulating material on which a resistance element may be wound or otherwise strung. As between this class (338) and the insulators of special application in other classes, this class (338) includes insulators which are constituent parts of the resistor as to have a resistance element wound or strung thereon. However, an insulator for supporting a resistance wire at one point thereon, this wire being strung in space in the manner of an aerial conductor is not classified here, but elsewhere. Resistive cable supports and brackets are classified elsewhere.

Boxes and housings which may constitute resistor housings which are limited by claimed structure to electrical use and not otherwise classifiable are classified elsewhere.

SECTION III - SUBCLASS REFERENCES TO THE CURRENT CLASS

SEE OR SEARCH THIS CLASS, SUBCLASS:

SECTION IV - REFERENCES TO OTHER CLASSES

SEE OR SEARCH CLASS:

SECTION V - GLOSSARY

BASE

Unless otherwise indicated an element along which the resistance element extends to impart a rigidity or reinforcement to the resistance element not otherwise present.

CONDUCTOR

A body which is essentially a carrier of electric current with a minimum of loss as by heating.

ELEMENT

Resistance element unless otherwise indicated.

INSULATOR

A body of such low conductivity that the flow of current therethrough can usually be neglected.

NEGATIVE RESISTOR

A resistor wherein the derivative of the voltage across the resistor with respect to the current passing through is negative over a portion of the current range.

RESISTANCE

The property of a mass of material to impede the flow of a steady or fluctuating current passing through the mass by conversion of electrical energy into heat.

RESISTANCE ELEMENT

The part of the resistor which actually possesses the resistance characteristic, and which may be a homogeneous mass of material having a resistance characteristic.

RESISTANCE TERMINAL

Ordinarily one of the spaced conductors in physical contact with the resistance element, and being appreciably more conductive (less resistive) than the resistance element. The terminals are for the purpose of connecting the resistance element in an external electric circuit. Since all resistors must include terminals in the sense that some structure is necessary to permit energization of the resistance element, the term "terminal" is sufficiently broad to include one of the free ends of the resistance element.

RESISTOR

An apparatus or device exhibiting only and significantly a resistance characteristic as above defined to the current flowing therethrough, the inductive or capacitive effects being negligible. A resistor includes essentially a resistance element and spaced terminals.

SEMICONDUCTOR

A body of solid material whose conductivity is considerably more than insulators, yet considerably less than metals.

TERMINAL

One of the resistance terminals unless otherwise indicated.

SUBCLASSES

1	COHERER TYPE
	This subclass is indented under the class definition.  Subject matter wherein the resistance element has the property of decreasing its resistance value upon the passage of a high frequency current therethrough; or together with structure which enables the resistor to return to its original resistance value upon termination of the high frequency current or to decohere. (1) Note. Usually the exciting high frequency current is a received high frequency wave, and the coherer is used as a radio detector. The resistance element is usually granular in nature; and the decohering is effected or facilitated as by particular chemical material, or by shock, stirring, agitating, or tapping. Where significant detector circuitry such as a resonant circuit is claimed with coherer, classification is elsewhere. SEE OR SEARCH THIS CLASS, SUBCLASS: 20+, for resistors whose resistance value is changed by an electric current and/or voltage. 32, for resistors whose resistance value is changed by a magnetic field. 68+, for mechanically variable resistors. SEE OR SEARCH CLASS: 257,  Active Solid-State Devices (e.g., Transistors, Solid-State Diodes),   subclass 43 for active solid-state type coherers. 329,  Demodulators,   subclasses 315+ for frequency demodulators and subclasses 345+ for phase demodulators.

2	STRAIN GAUGE TYPE
	This subclass is indented under the class definition.  Subject matter wherein a flexible or deformable solid mass of resistance material is formed as a wire, strip, or other elongated mass, the resistance value of the mass between points along its length changing with deformation between the points, as a change in length or cross-sectional area; the wire, strip, or other elongated mass being shaped or configured to be applied to a device which is subject to deformation in a direction along the length of the elongated mass, the mass being adapted to deform with the device; or wherein the wire, strip, or other elongated mass includes structure, such as adhesive material on a flexible base, for facilitating application to the device which is subject to deformation; or wherein the wire, strip, or other elongated mass is combined with and deformable with a device which is subject to deformation or other change in dimension and not otherwise classifiable. (1) Note. As between this subclass and Class 73, Measuring and Testing, when the meter, Wheatstone bridge connection, or other current measuring device in series with the resistor is claimed, classification is in Class 73. SEE OR SEARCH THIS CLASS, SUBCLASS: 13+, for variable resistors generally actuated by a condition sensing device. 114, for deformable resistors generally. SEE OR SEARCH CLASS: 33,  Geometrical Instruments,   subclasses 125+ for distance determining devices; subclasses 174+ for limit gauges; and subclasses 204+ for direction indicators. 73,  Measuring and Testing,   subclasses 763+ for an electrical stress or strain measuring system; and subclasses 862+ for dynamometers. See also (1) Note above.

3	With temperature compensation
	This subclass is indented under subclass 2.  Subject matter including resistance structure in series with the strain gauge resistor, whose resistance value increases or decreases significantly with the temperature change, for the purpose of offsetting at least partly the effect of temperature change on the strain gauge resistor or furnishing a reference for comparison purposes as in the Wheatstone bridge network in which the strain gauge resistor may be connected. (1) Note. The temperature coefficient of the resistance structure may have the same or opposite sign (positive or negative) as the temperature coefficient of the strain gauge resistor. SEE OR SEARCH THIS CLASS, SUBCLASS: 7+, for resistors having resistance value temperature compensation.

4	Fluid- or gas pressure-actuated
	This subclass is indented under subclass 2.  Subject matter wherein the strain gauge is secured to or otherwise mechanically linked with a diaphragm, bellows, piston, or other device which is adapted to move or deform by a compresses fluid or gas acting thereon. SEE OR SEARCH THIS CLASS, SUBCLASS: 36+, for mechanically variable resistors generally with a fluid or gas pressure sensing actuator. SEE OR SEARCH CLASS: 73,  Measuring and Testing,   subclasses 720 and 726 for fluid pressure gauges of the current generating or modifying type. 324,  Electricity: Measuring and Testing,   subclasses 106+ for electrical time and speed measuring.

5	Dynamometer type
	This subclass is indented under subclass 2.  Subject matter wherein the device to which the strain gauge is attached is responsive to a force applied thereto, the portion of the device to which the strain gauge is attached being deformed by this force to deform the strain gauge. (1) Note. In this subclass, the device converts the applied force to strain or deformation. (2) Note. When the resistor strain gage is disclosed for making a quantitative measurement, proper classification is in the measuring class (see search notes below). SEE OR SEARCH CLASS: 73,  Measuring and Testing,   subclasses 862+ for dynamometer measuring devices. 177,  Weighing Scales,   for weighing scales.

6	Extensometer type
	This subclass is indented under subclass 2.  Subject matter wherein the strain gauge includes structure, such as pins, for engaging two spaced points for sensing any changes in the spacing of these two points, and for transmitting this sensed spacing change to the strain gauge to cause deformation thereof. SEE OR SEARCH CLASS: 33,  Geometrical Instruments,   subclasses 125+ for distance measuring instruments generally. 73,  Measuring and Testing,   subclasses 763+ for an electrical stress or strain measuring system and involving current generation or modification.

7	RESISTANCE VALUE TEMPERATURE-COMPENSATED
	This subclass is indented under the class definition.  Subject matter wherein the resistance element is formed of materials whose resistance value changes a relatively small amount with a change in the temperature of the element; or wherein one resistance material is combined with another resistance material in the same or different resistance elements, the change of resistance value of one material with the temperature of the material being such as to offset at least partly the change of resistance value of the other material with the temperature of this material, the materials being always at the same temperature, e.g., one material has a positive temperature coefficient and the other material has a correspondingly negative temperature coefficient; or wherein the support or actuator for the resistor includes material or structure which offsets at least partly the effect of or resists dimensional changes due to temperature change in the support or actuator, which otherwise would result in a change in resistance value. (1) Note. Only compensation structure is classified here which at least partly controls or modifies the resistance value of the resistor. Resistors with temperature compensated supports which merely maintain the position of the resistor unchanged with temperature change, for example, are classified in subclass 316 below. SEE OR SEARCH THIS CLASS, SUBCLASS: 3, for strain gauge type resistors with temperature compensation. 14, for resistors whose resistance value is responsive to a plurality of conditions. 25+, for resistors whose resistance value is responsive to ambient temperature. 316, for supports which compensate for expansion or contraction with temperature. See also (1) Note above. SEE OR SEARCH CLASS: 361,  Electricity: Electrical Systems and Devices,   subclass 140 for electric circuits for relays and electromagnets having means compensating for thermal changes.

8	Temperature-compensated actuator
	This subclass is indented under subclass 7.  Subject matter, including structure or material which is directly operative on the actuator to offset the effect of or reduce or prevent a change in dimension of the actuator due to temperature change.

9	With additional compensating resistor or resistance element
	This subclass is indented under subclass 7.  Subject matter including an additional resistor or resistance element, whose temperature coefficient is of opposite sign (positive or negative) from the temperature coefficient of the original resistor. SEE OR SEARCH THIS CLASS, SUBCLASS: 3, for strain gauge type resistors including a temperature compensating resistor. 48, for plural separate diverse resistors. 322, for plural resistance elements in parallel between terminals.

10	Filament or wire resistance elements
	This subclass is indented under subclass 9.  Subject matter wherein both the resistance elements or the resistance elements of both resistors are elongated in shape, as wires or filaments.

11	REFLECTOR DIRECTS HEAT ON ELEMENT
	This subclass is indented under the class definition.  Subject matter including structure which is spaced from and positioned with respect to the resistance element to redirect any heat impinging on the structure from an external source onto the resistance element, or to redirect any heat produced by the resistance element and impinging on the structure back on the resistance element. (1) Note. The heat reflectors in this subclass are restricted to directing heat toward the resistance element or to redirecting the heat produced by the element back to the element. Where the heat produced by the element is directed by reflectors for heating some object other than the element itself classification is in the electric heating class (see the search note below) SEE OR SEARCH THIS CLASS, SUBCLASS: 226+, for a resistor with a heat insulating housing, which may even protect the resistor from external heat by reflection, i.e., prevent the external heat going to the resistance element; and especially subclasses 234+ for a resistor with a gaseous or vacuum layer between the element and the casing or housing. 334, for a resistor with a heat protecting shield other than a casing, and not classified elsewhere. SEE OR SEARCH CLASS: 219,  Electric Heating,   especially subclass 34 for where the heat produced by the element is directed by reflectors for heating some object other than the element itself; subclass 540 for electric heating radiators. See also (1) Note above. 432,  Heating,   subclass 50 for shielding devices in connection with heating furnaces or other hot objects acting as a screen or baffle to heat.

12	MOVABLE MAGNET ACTUATES RESISTOR THROUGH HOUSING OR PARTITION
	This subclass is indented under the class definition.  Subject matter including a mechanically variable resistor together with a partition, wall, or housing; and a movable magnet, usually permanent, which when moved is effective by its field through the partition, wall, or housing to change the mechanical setting of the variable resistor and thus change the resistance value of the variable resistor. (1) Note. Usually a second magnet is disposed on the opposite side of the partition, wall, or housing from the movable magnet, the second magnet being mechanically linked with the variable resistor and being adapted to be moved by the field of the first movable magnet. SEE OR SEARCH THIS CLASS, SUBCLASS: 1, for coherer type resistors. 32, for resistors generally whose resistance value is responsive to a magnetic field or compass. 103+, and 116, for mechanically variable resistors with an electromagnetic operator. SEE OR SEARCH CLASS: 310,  Electrical Generator or Motor Structure,   subclass 103 for magnetic field type clutches or brakes.

13	RESISTANCE VALUE RESPONSIVE TO A CONDITION
	This subclass is indented under the class definition.  Subject matter including a resistor usually mechanically variable to change its resistance value, linked with actuating structure which senses and responds significantly well to a particular stimulus or condition or change in such stimulus or condition; or including a resistor, usually nonmechanically variable, having the property as by shape or chemical composition of changing its resistance value significantly well in response to a particular stimulus or condition or change in such stimulus or condition; and usually together with structure as part of the resistor or in addition to the resistor for applying or facilitating the application of this stimulus or condition to the resistor. (1) Note. For classification here the actuator must be something more than merely adapted to have a force applied thereto for the actuation of the mechanical variable or adjustable resistor, as a knob, pedal, or handle. The actuator must sense the condition or change in condition, and respond in some manner as by moving or deforming. When a meter Wheatstone bridge connection or other indicating device for indicating the current passing through a resistor together with the resistor and condition sensing device are recited, classification is not here, but in such Classes as 33, Geometrical Instruments and 73, Measuring and Testing. 374, Thermal Measuring and Testing, Microphones are classified in Class 381, Electrical Audio Signal Processing Systems and Devices, even when the output circuitry is not recited. Similarly, resistive phonograph pickups are classified in Class 369, Dynamic Information Storage or Retrieval, subclass 152. However a mere variable resistor adapted to be actuated by a stylus (unclaimed) is classified in this subclasses 13+. A mere statement of use as a resistor whose value changes in response to a sensed condition is not sufficient for classification here. The structure or chemical composition which at least contributes to this result must be recited in the claims. SEE OR SEARCH THIS CLASS, SUBCLASS: 2+, for a strain gauge resistor with a particular condition sensing actuator. SEE OR SEARCH CLASS: 33,  Geometrical Instruments,   appropriate subclasses, for geometrical instruments. 73,  Measuring and Testing,   appropriate subclasses, for measuring and testing devices. 177,  Weighing Scales,   subclass 211 for a weighing scale including an electrical strain gauge. 200,  Electricity: Circuit Makers and Breakers,   subclasses 52+ for electric circuit makers and breakers of special application. 318,  Electricity: Motive Power Systems,   subclasses 445+ for systems of automatic motor control. 323,  Electricity: Power Supply or Regulation Systems,   subclasses 293+ for automatic impedance systems. 334,  Tuners,   subclasses 5+ for tuners which are responsive to a condition. 340,  Communications: Electrical,   especially subclasses 177+ and 500+, for electrical systems for telemetering or indicating electrically a sensed condition. 361,  Electricity: Electrical Systems and Devices,   subclass 91.2 for overvoltage protection with resistor sensor. 369,  Dynamic Information Storage or Retrieval,   subclass 152 for resistive phonograph pickups. 374,  Thermal Measuring and Testing,   appropriate subclasses for measuring and testing of thermal quantities.

14	Plural conditions
	This subclass is indented under subclass 13.  Subject matter including two or more actuating structures together with a variable resistor each responsive to an independent stimulus or condition, which may be of the same or different type; or including a resistor whose element has the property of changing its resistance value particularly well in response to two or more independent conditions or stimuli applied thereto; or including a variable resistor whose element is responsive directly to a condition together with an actuator responsive to an independent condition.

15	Photoconductive (e.g., light sensitive)
	This subclass is indented under subclass 13.  Subject matter wherein the resistor is formed of a material whose resistance value changes materially upon the application of light, infrared radiation, or ultraviolet radiation to the resistor, or upon a change in the intensity of this radiation applied to the resistor together with any structure which facilitates the application of light or ultra violet or infrared radiation to the resistor. SEE OR SEARCH CLASS: 136,  Batteries: Thermoelectric and Photoelectric,   subclass 89 for primary photoelectric batteries. 250,  Radiant Energy,   subclasses 200+ for photocell circuits and apparatus. 252,  Compositions,   subclass 501 for light sensitive conductive compositions. 374,  Thermal Measuring and Testing,   subclasses 121+ for radiation type thermometers.

16	With vibration control
	This subclass is indented under subclass 15.  Subject matter including structure for eliminating or reducing vibration or offsetting the effect thereof, as a shock absorbing support for the resistance element. SEE OR SEARCH THIS CLASS, SUBCLASS: 98, for mechanically adjustable or variable resistors with motion damping and/or vibration control means. 171, for a variable resistor with a contact slidable on the resistance element, the contact having plural element engaging portions which may reduce the effect of vibration. 315+, for resistors generally with mounting or supporting means, which may include anti-vibration structure.

17	Plural resistance elements (e.g., mosaic)
	This subclass is indented under subclass 15.  Subject matter including two or more resistors as there defined or a single resistor having two or more elements. (1) Note. Usually the resistors or elements are arranged in a planar pattern as a mosaic. SEE OR SEARCH THIS CLASS, SUBCLASS: 320, for plural supported or mounted resistors. 322, for resistors having a plurality of elements between terminals. SEE OR SEARCH CLASS: 427,  Coating Processes,   subclasses 58+ for coating processes, per se, wherein the product has utility as electrical article. 428,  Stock Material or Miscellaneous Articles,   appropriate subclasses, for a plural layer stock material product, one layer being of resistance material and another layer being conductive, note especially subclasses 195+ for a discontinuous or differential coating, impregnation or bond.

18	Infrared radiation
	This subclass is indented under subclass 15.  Subject matter wherein the material of which the resistor is formed changes its resistance value materially upon the application of infra red radiation thereto. SEE OR SEARCH THIS CLASS, SUBCLASS: 25+, for resistors whose resistance value changes with ambient temperature.

19	With transparent housing
	This subclass is indented under subclass 15.  Subject matter including a casing or covering such as a glass or quartz envelope containing the photoconductive element, at least a portion of the casing or covering freely passing the radiant energy which impinges on the photoconductive element. SEE OR SEARCH THIS CLASS, SUBCLASS: 184, and 199, for mechanically variable resistors with housings. 226+, for incased, embedded, or housed resistors generally; and especially subclasses 234+, for such resistors with gaseous or vacuum spacing between the element and the casing or housing.

20	Current and/or voltage (e.g., ballast resistor)
	This subclass is indented under subclass 13.  Subject matter wherein the resistor is chemically constituted or otherwise formed to change its resistance value in response to an electric current passing through or a voltage impressed across the resistor, or wherein the resistor includes structure or composition which enables the resistor to change its resistance value in response to a current or voltage applied to a circuit other than to the resistor itself; as to an electric heater with a heat conducting path to the resistor. (1) Note. Usually the current increases the temperature of the resistor either directly or indirectly, and the resistor has an appreciable resistor temperature coefficient to cause the resistance value to change. In the case of the so-called voltage responsive resistors, a voltage change often produces a current change which in turn changes the resistance value as through the heating effect of the current. However, some resistors here classified do change value directly with the voltage gradient existing therein. SEE OR SEARCH THIS CLASS, SUBCLASS: 25+, for resistors whose resistance value changes with ambient temperature. 103+, and 116, for mechanically adjustable or variable resistors with an electromagnetic operator, such as an electric motor. SEE OR SEARCH CLASS: 313,  Electric Lamp and Discharge Devices,   subclasses 341+ for electric lamp and discharge device filaments. 323,  Electricity: Power Supply or Regulation Systems,   subclasses 293+ for impedance systems automatically responsive to voltage and/or current.

21	Voltage surge-responsive or lightning arrester type
	This subclass is indented under subclass 20.  Subject matter wherein the resistance element is formed of material whose resistance value changes sharply and often discontinuously upon a change in terminal voltage from a low to a relatively high value or upon a rise in the terminal voltage above a threshold value. SEE OR SEARCH CLASS: 361,  Electricity: Electrical Systems and Devices subclasses 1+ for safety and protection systems and subclasses 117+ for high voltage dissipators such as lightning arrester systems.

22	Thermistor type
	This subclass is indented under subclass 20.  Subject matter wherein the resistance element is formed of a semi-conductor material and has a relatively high temperature coefficient, which is usually negative. SEE OR SEARCH THIS CLASS, SUBCLASS: 25+, for thermistors whose resistance values are changed by ambient temperature. SEE OR SEARCH CLASS: 257,  Active Solid-State Devices (e.g., Transistors, Solid-State Diodes),   subclasses 53 , 108, and 467-470 for active solid-state type temperature responsive devices. 323,  Electricity: Power Supply or Regulation Systems,   subclass 294 and subclasses 364+ for impedance systems responsive to a thermal condition.

23	Indirectly heated
	This subclass is indented under subclass 22.  Subject matter wherein a resistance heater for the thermistor is provided other than the thermistor resistance and in a current circuit distinct from the current circuit through the thermistor. (1) Note. The heater circuit may be in series or shunt with the thermistor, or be in another electrical system. SEE OR SEARCH THIS CLASS, SUBCLASS: 24, for resistors generally whose resistance value changes in response to a current which indirectly heats the resistance element. SEE OR SEARCH CLASS: 219,  Electric Heating,   subclasses 50+ for electrical resistance heaters.

24	Indirectly heated
	This subclass is indented under subclass 20.  Subject matter wherein a resistance heater for the resistor is provided other than the resistance element and in a current circuit distinct from the current circuit through the element. (1) Note. The heater circuit may be in series or shunt with the resistance element or be in another electrical system. SEE OR SEARCH THIS CLASS, SUBCLASS: 23, for thermistor type resistors whose resistance value changes in response to a current which indirectly heats the resistance element. SEE OR SEARCH CLASS: 219,  Electric Heating,   subclasses 50+ for electrical resistance heaters.

25	Ambient temperature
	This subclass is indented under subclass 13.  Subject matter wherein the resistance element includes material which effects a significant change, such as sharp, rapid, or pronounced, in the resistance value of the element with a change in the surrounding temperature, or together with structure which facilitates this change in resistance value with the surrounding temperature; or including a mechanically adjustable or variable resistor together with structure whose shape, configuration or any other dimension changes with a change in surrounding temperature, the structure being linked with the adjustable or variable resistor to change in resistance value with the change in shape, configuration or other dimension occurring in the temperature sensing structure. SEE OR SEARCH THIS CLASS, SUBCLASS: 7+, for resistors with compensation for a change in resistance value due to temperature change. 20+, for resistors whose resistance value changes in response to a current or voltage, which may involve a change in the ambient temperature of the resistor. 51, for resistors with heat dissipating projections. 53+, for resistors with cooling gas or liquid circulation. 59, for resistors with heat storing. SEE OR SEARCH CLASS: 236,  Automatic Temperature and Humidity Regulation,   appropriate subclasses, for automatic temperature controls, especially the subclasses found under THERMOSTATIC. 313,  Electric Lamp and Discharge Devices,   subclass 14 for temperature modified pyroelectric type devices. 323,  Electricity: Power Supply or Regulation Systems,   subclass 294 and subclass 364+ for thermally responsive impedance systems. 340,  Communications: Electrical,   subclasses 584+ and 577+ for electrical systems generally responsive to temperature and flame, respectively. 374,  Thermal Measuring and Testing,   subclasses 183+ for current modifying type thermometers.

26	Cable or tape type (e.g., fire-detecting cable)
	This subclass is indented under subclass 25.  Subject matter wherein the resistor is flexible or deformable and has an elongated shape with substantially uniform external size over its length, the resistance element extending between the ends of the resistor. SEE OR SEARCH THIS CLASS, SUBCLASS: 212, for tape type resistors generally. 214, for cable type resistors generally.

27	Liquid contact or element
	This subclass is indented under subclass 25.  Subject matter wherein the resistance element or contact is a liquid, the liquid sensing the change in the surrounding temperature. SEE OR SEARCH THIS CLASS, SUBCLASS: 80+, and 222, for mechanically variable and fixed resistors respectively having liquid resistance elements. 94, 151 and 156, for mechanically variable resistors having a liquid contact.

28	Probe type
	This subclass is indented under subclass 25.  Subject matter wherein the resistor is formed as an elongated rigid unit, one end being free and the other end including the resistor terminal or the portions of the terminals connecting the external circuitry, as well as any structure for manipulating the unit, such as a handle, or for securing the unit to supporting structure. (1) Note. Usually the resistance element is enclosed in an elongated casing which forms the exterior of the probe. SEE OR SEARCH THIS CLASS, SUBCLASS: 229, for probe type incased, embedded or housed resistors generally. SEE OR SEARCH CLASS: 324,  Electricity: Measuring and Testing,   subclass 149 for electricity measuring devices including a probe.

29	Mechanically adjustable or variable
	This subclass is indented under subclass 28.  Subject matter including a mechanically adjustable or variable resistor as defined in subclass 68 below. SEE OR SEARCH THIS CLASS, SUBCLASS: 68+, for mechanically adjustable or variable resistors generally.

30	Terminal forms casing or housing
	This subclass is indented under subclass 28.  Subject matter wherein one or both of the terminals form a substantial part of the probe casing or housing. SEE OR SEARCH THIS CLASS, SUBCLASS: 271, for resistors generally one of whose terminal forms a casing or housing.

31	Mechanically adjustable or variable
	This subclass is indented under subclass 25.  Subject matter including a mechanically adjustable or variable resistor as defined in subclass 68 below. SEE OR SEARCH THIS CLASS, SUBCLASS: 68+, for mechanically adjustable or variable resistors generally.

32	Magnetic field or compass (e.g., Hall effect type)
	This subclass is indented under subclass 13.  Subject matter wherein the resistance element includes material whose resistance value is dependent on a magnetic field applied directly thereto, or together with means for applying or facilitating the application of a magnetic field to this material of the resistance element; or wherein a resistor is mechanically linked with the magnet of a magnetic compass to be actuated by this magnet. SEE OR SEARCH THIS CLASS, SUBCLASS: 43, for resistors responsive to inertia devices, such as a gyro compass. 103+, for a compressible type resistor with an electromagnetic operator. 116, for mechanically variable resistors generally with an electromagnetic operator such as an electric motor. SEE OR SEARCH CLASS: 257,  Active Solid-State Devices (e.g., Transistors, Solid-State Diodes),   appropriate subclasses, including subclasses 108 , 414, and 421-427 for devices responsive to magnetic field. 329,  Demodulators,   appropriate subclasses for magnetic demodulators using, for example, the Hall effect.

33	Float actuator
	This subclass is indented under subclass 13.  Subject matter wherein an adjustable resistor is combined with a float, which is mechanically linked with the resistor actuator to vary the resistance value in accordance with the position of the float. (1) Note. The subject matter in this subclass is usually a subcombination of a liquid level or depth gauge as classified in Class 73, Measuring and Testing, subclasses 305+. Where the indicator is recited as an added element, classification is in subclasses 305+ of Class 73. The mere recitation of the tank broadly does not preclude classification in this class (338). Where details of the tank are recited, classification is elsewhere such as Class 137, Fluid Handling, subclass 560 for a tank with an out- flow pipe together with a float operated rheostat. SEE OR SEARCH THIS CLASS, SUBCLASS: 34+, for resistors whose resistance value is dependent on the gas, vapor, or moisture absorbed or collected. 36+, for mechanically variable resistors with structure responsive to fluid pressure. 68+, for mechanically adjustable or variable resistors, per se. SEE OR SEARCH CLASS: 73,  Measuring and Testing,   subclasses 305+ for liquid level or depth gauges including a float operated rheostat; and subclasses 451+ for specific gravity or density measurement of a liquid including a float operated rheostat. See also (1) Note above. 137,  Fluid Handling,   appropriate subclasses, for fluid handling systems. See also (1) Note above. 340,  Communications: Electrical,   subclasses 177+ for float operated telemetric systems.

34	Gas, vapor, or moisture absorbing or collecting
	This subclass is indented under subclass 13.  Subject matter including material or structure which readily absorbs or collects or facilitates the absorption or collection of fluent material such as liquids, gases, vapors, or humidity to which the resistor may be exposed, and usually which relinquishes all or part of the fluent material so absorbed or collected upon reduction in the intensity or termination of the exposure thereto, the material so collected or absorbed usually providing the electrical resistance, the value of the resistance depending on the amount of material absorbed. (1) Note. The fluent material may be collected on the surface or absorbed within other material of the resistor. SEE OR SEARCH THIS CLASS, SUBCLASS: 80+, for mechanically adjustable or variable liquid resistors. SEE OR SEARCH CLASS: 23,  Chemistry: Physical Processes,   subclasses 230+ and 253+ for analytical and analytical control methods and apparatus respectively. 73,  Measuring and Testing,   subclasses 73+ for measuring the moisture content or absorption characteristics of materials. 200,  Electricity: Circuit Makers and Breakers,   subclasses 61.04+ for circuit making or breaking devices responsive to liquid or moisture. 318,  Electricity: Motive Power Systems,   subclass 483 for motor control systems automatically operative in response to moisture content or wetness. 340,  Communications: Electrical,   subclass 602 , for electrical communications systems automatically responsive to moisture or humidity; and subclasses 628+ and 632+ for such systems responsive to smoke and gas; respectively.

35	Humidity
	This subclass is indented under subclass 34.  Subject matter wherein the resistor is peculiarly adopted to collect or absorb moisture from the air. SEE OR SEARCH CLASS: 73,  Measuring and Testing,   subclasses 335+ for hygrometers.

36	Fluid- or gas pressure-actuated
	This subclass is indented under subclass 13.  Subject matter wherein the condition sensed is fluid or gas pressure and the resistor actuator engages this fluid or gas and is mechanically moved or deformed by the pressure of this fluid or gas. SEE OR SEARCH THIS CLASS, SUBCLASS: 4, for strain gauge resistors which are fluid or gas actuated. 33, for float actuated resistors. SEE OR SEARCH CLASS: 73,  Measuring and Testing,   subclasses 290+ for liquid depth gauges; and subclasses 700+ for fluid pressure gauges. 340,  Communications: Electrical,   subclasses 603+ for fluent material operated alarms.

37	Vehicle tire inflation
	This subclass is indented under subclass 36.  Subject matter wherein the condition sensed is the air pressure in the tire of a vehicle, and including structure for sensing this pressure and not otherwise classifiable. SEE OR SEARCH THIS CLASS, SUBCLASS: 50, for resistors mounted on wheels or vehicles. SEE OR SEARCH CLASS: 73,  Measuring and Testing,   subclasses 146.3+ for direct pressure reading of tire inflation. 137,  Fluid Handling,   subclasses 227+ for tire stem inflation means with a gauge or indicator. 200,  Electricity: Circuit Makers and Breakers,   subclasses 61.22+ for pneumatic tire inflation responsive switches. 340,  Communications: Electrical,   subclass 58 for electrical systems automatically responsive to tire deflation.

38	Liquid resistance element or contact
	This subclass is indented under subclass 36.  Subject matter wherein a liquid resistance element or contact is arranged to rise and fall over contact or resistance structure to give a variable resistance according to the condition sensed. SEE OR SEARCH THIS CLASS, SUBCLASS: 80+, for mechanically variable resistors having liquid resistance elements. 94, for a mechanically adjustable resistor having a liquid short circuiting contact. 151, for a mechanically variable resistor having a liquid contact in which the resistance element moves. 156, for a mechanically variable resistor with a liquid contact. 222, for a fixed resistor having a liquid element. SEE OR SEARCH CLASS: 73,  Measuring and Testing,   subclass 750 for liquid column fluid pressure gauges such as manometers.

39	Piston
	This subclass is indented under subclass 36.  Subject matter wherein the resistor actuator is a piston or plunger. SEE OR SEARCH THIS CLASS, SUBCLASS: 33, for a resistor actuated by a float. SEE OR SEARCH CLASS: 73,  Measuring and Testing,   subclass 746 for fluid pressure gauges having a piston as the pressure responsive element.

40	Bourdon tube
	This subclass is indented under subclass 36.  Subject matter wherein the resistor actuator is a Bourdon tube. SEE OR SEARCH CLASS: 73,  Measuring and Testing,   subclass 734 for fluid pressure gauges having a Bourdon tube for their pressure responsive element. 200,  Electricity: Circuit Makers and Breakers,   subclass 81.8 for Bourdon tube operated switches.

41	Bellows or capsule
	This subclass is indented under subclass 36.  Subject matter wherein a cylindrical or cup shaped expansible chamber has side walls comprising sections of alternately larger and smaller cross-sections which make up a single fluid or gas chamber having a zigzag or pleated wall, or wherein an expansible chamber device includes a plurality of movable walls, two or more of which are of the flexible sheet material or diaphragm type whereby vertical collapse or expansion of the chamber is facilitated. SEE OR SEARCH CLASS: 137,  Fluid Handling,   subclasses 786 and 793+ for expansible chamber fluid handling devices of the bellows or capsule type.

42	Diaphragm
	This subclass is indented under subclass 36.  Subject matter wherein the resistor actuator is a diaphragm, or a flexible or deformable wall or casing structure. SEE OR SEARCH CLASS: 73,  Measuring and Testing,   subclasses 262+ for volume or rate of flow meters with a diaphragm or collapsible wall; subclasses 278 and 279+ for diaphragm mountings and diaphragms for such meters; and subclasses 719 and 725 for fluid pressure gauges including a diaphragm.

43	Gravity stabilized or inertia actuator
	This subclass is indented under subclass 13.  Subject matter wherein the actuator or reference for the actuator is a mass which is at least partly free to operate under the effect of its inertia, or under the effect of its weight to seek a lower level and thus maintain a vertical stabilization as for reference purposes. SEE OR SEARCH CLASS: 73,  Measuring and Testing,   subclasses 652+ for vibration testing with an inertia sensing element.

44	Liquid resistance element or contact
	This subclass is indented under subclass 43.  Subject matter wherein the resistance element or its contact is a liquid, and the actuator is this liquid element or contact, which is operated by its inertia or level seeking characteristic. SEE OR SEARCH THIS CLASS, SUBCLASS: 80+, and 222, for a mechanically variable and fixed resistor respectively having a liquid resistance element. 94, 151 and 156, for mechanically variable resistors having liquid contacts; especially subclass 151, for such resistors whose elements move and whose liquid contact is fixed at the lowest level by gravity.

45	Centrifugal
	This subclass is indented under subclass 43.  Subject matter wherein the actuator is subject to rotation to thus develop a centrifugal force to control the variable resistor. SEE OR SEARCH CLASS: 264,  Plastic and Nonmetallic Article Shaping or Treating: Processes,   subclasses 15+ for centrifugal speed responsive devices. 318,  Electricity: Motive Power Systems,   subclass 325 for electric motors having a centrifugally operated speed control

46	Pendulum
	This subclass is indented under subclass 43.  Subject matter wherein the actuator for the variable resistor is a pendulum. SEE OR SEARCH CLASS: 33,  Geometrical Instruments,   subclasses 215+ for pendulum type direction indicators and subclass 366.24 for a level having a pendulum controlled electrical indicator and subclass 366.24 for a level having a pendulum controlled electrical indicator. 73,  Measuring and Testing,   subclasses 862.381+ for pendulum type dynamometers.

47	Force-actuated
	This subclass is indented under subclass 13.  Subject matter wherein the actuator is constructed to facilitate the application of a force thereto, and to mechanically move or deform in response to this force to provide a mechanical movement for the operation of the variable resistor, the force being substantially greater than necessary to operate the resistor. (1) Note. Since force is the most common method of operating mechanically variable resistors, a mere knob, pedal or handle as an actuator is not sufficient for classification here. The force sensing mechanism must be able to respond directly to forces substantially greater than or bearing little relationship to the force necessary to adjust the variable resistor or to overcome any spring loading of the variable resistor for classification in this subclass. Pushing, pulling and torque are examples of the forces sensed by the subject matter of this subclass. (2) Note. When the resistor strain gage is disclosed for making a quantitative measurement, proper classification is in Class 73, subclasses 862+. SEE OR SEARCH THIS CLASS, SUBCLASS: 5, for dynamometer type strain gauge resistors. 36+, for a variable resistor with a condition sensing actuator producing a force by a fluid or gas pressure. 68+, for mechanically adjustable or variable resistors; especially subclasses 99+ for such resistors of the compressible type; and subclass 167, for such resistors with spring loaded angularly slidable contacts. SEE OR SEARCH CLASS: 73,  Measuring and Testing,   subclasses 133+ for dynamometers. 177,  Weighing Scales,   appropriate subclasses, for weighing scales.

48	PLURAL SEPARATE DIVERSE RESISTORS
	This subclass is indented under the class definition.  Subject matter wherein a first resistor is combined with a physically distinct second resistor which is significantly structurally different from the first resistor. (1) Note. For classification here the two resistors must be claimed together with the distinction of one resistor over the other. A mere claimed difference in dimensions or resistance values as one resistor being coarse and the other fine is not a sufficient distinction for classification herein. The claimed distinctions for classification here must be in the structure or shape of the resistor or the resistor combined with perfecting subject matter, as for example when each resistor is a different species and is classified in different subclasses in this schedule. SEE OR SEARCH THIS CLASS, SUBCLASS: 9, for a resistor with an additional temperature compensating resistor. 23, and 24, for indirectly heated current and/or voltage responsive resistors. 49, for shunt type resistors which may have diverse terminals. 67, for resistors combined with diverse nonelectrical devices. 122, for mechanically variable resistors with contacts movable over coarse and fine resistance elements. 286, for resistors having both a helical and a zigzag configuration. 324, for single resistors having diverse terminals.

49	SHUNT TYPE
	This subclass is indented under the class definition.  Subject matter wherein the resistor is peculiarly adapted for shunting a metering instrument, the resistor terminals usually being of large mass and having a plurality of sets of connectors, one smaller set for the instrument and the other larger set for the main current leads, the resistance element extending therebetween and usually being flat or formed with ventilating means such as fine or vented passages, or with a plurality of separate current paths to present a large cooling surface to maintain uniform temperature and prevent change in the resistance value or the resistor. SEE OR SEARCH THIS CLASS, SUBCLASS: 51, for resistors with heat dissipating projections, e.g., vanes. 322, for plural resistance elements in parallel between terminals. 324, for fixed resistors having diverse terminals. SEE OR SEARCH CLASS: 324,  Electricity: Measuring and Testing,   subclass 126 for measuring or testing instruments having coupling means, e.g., shunts.

50	MOUNTED ON WHEELS OR VEHICLE
	This subclass is indented under the class definition.  Subject matter wherein the resistor is provided with wheels for increasing the mobility of the vehicle, or wherein the resistor is mounted on a vehicle especially adapted for carrying only the resistor together with its operating structure or a plurality of such resistors. (1) Note. Where the vehicle is adapted for other purposes then merely carrying the resistor and its operating structure, classification is not here. See also the Search Notes below. SEE OR SEARCH THIS CLASS, SUBCLASS: 67, for resistors with diverse nonelectrical devices. See also (1) Note above. 197, for mechanically variable resistors with supports. 315+, for resistors generally with mounting or supporting means. SEE OR SEARCH CLASS: 105,  Railway Rolling Stock,   subclass 61 for electric railway cars including a controlling resistor. 180,  Motor Vehicles,   subclass 65 for electric vehicles generally; and subclasses 77+ for such vehicles including electric motor controlling devices, which may be resistors.

51	WITH HEAT DISSIPATING PROJECTIONS (E.G., VANES)
	This subclass is indented under the class definition.  Subject matter wherein a surface of the resistance element, casing, terminal, or other resistance structure is enlarged or increased in area over what is otherwise necessary by a projecting portion integral therewith or attached thereto, such as vanes, fins, or corrugations, to increase the heat radiated, dissipated, or otherwise transferred from the surface structure of the resistor to the surrounding or adjacent medium. SEE OR SEARCH THIS CLASS, SUBCLASS: 49, for shunt type resistors. 53+, for resistors with cooling gas or liquid circulation. 159, for a mechanically adjustable or variable resistor with a heat conducting or distributing path. 226+, for resistors generally with heat conducting casings or housings. SEE OR SEARCH CLASS: 165,  Heat Exchange,   subclass 185 for a fin or heat transmitter, per se. 219,  Electric Heating,   subclass 34 for heating radiators.

52	Granular, powdered, or transversely stacked resistance element
	This subclass is indented under subclass 51.  Subject matter wherein the resistance element is granular or powdered in form or is formed as a plurality of layers or other distinct masses stacked or piled transversely to the direction of current flow through the resistance element; i.e., so that the current flowing through the resistance element will flow from mass to mass. SEE OR SEARCH THIS CLASS, SUBCLASS: 54, for resistors with cooling gas or liquid circulation, and having granular powdered or transversely stacked elements. 99+, for mechanically variable resistors including surfaces pressed together for adjustment purposes, e.g., compressible type; and subclass 115 for such resistors generally whose elements are in piled or stacked layers. 204+, for resistors generally whose elements are piled or stacked between terminals. 223+, for resistors having granular or powdered elements.

53	WITH COOLING GAS OR LIQUID CIRCULATION
	This subclass is indented under the class definition.  Subject matter wherein the resistor includes structure which conveys a cooling gas or liquid to, from or through the resistor, or which permits a cooling gas or liquid to move to or from the resistor for the purpose of cooling the resistor by conveying away the heat produced by the resistor. (1) Note. Subject matter in this subclass is very similar to subject matter in Class 219, Electric Heating, subclasses 50+, since cooling a resistor by gas or liquid is analogous to heating gas or liquid with a resistor. In the resistors in this subclass (53) the heat produced is usually incidental and undesired, and the fluid or gas dissipates this heat. In the heating resistors of Class 219 the resistor is adapted for heating purposes as opposed to impedance purposes, and the heat produced is distributed or directed for such heating purposes as opposed to mere dissipation. However, a mere resistor with heating or cooling fluid or gas circulation, even though designated as a heater, is classified in this subclasses (53+). For classification in Class 219, structure must be claimed which adapts the resistor, or the fluid gas circulating structure for heating purposes. See also the Notes under the Class Definition for the general lines between this class (338) and Class 219. (2) Note. A resistor with a liquid gas or vacuum enclosing casing is not classified here even though the liquid or gas is of heat conducting material, but in such subclasses as 231 and 234+ below. For classification in this subclasses (53+) the liquid or gas must circulate. SEE OR SEARCH THIS CLASS, SUBCLASS: 7+, for resistors with temperature compensation. 231, for resistors generally whose elements are incased in a liquid. See also (2) Note above. 234+, for resistors generally with a gaseous or vacuum spacing between the element and the casing or housing. See also (2) Note above. SEE OR SEARCH CLASS: 62,  Refrigeration,   appropriate subclasses, for refrigeration devices. 165,  Heat Exchange,   appropriate subclass for heat transferring devices generally. 219,  Electric Heating,   especially subclasses 50+ , and 280+ for electric resistance air and liquid heaters. See also (1) Note above.

54	Element granular, powdered, or stacked between terminals
	This subclass is indented under subclass 52.  Subject matter wherein the resistance element is granular or powdered in form or is formed as a plurality of layers or other distinct masses stacked or piled transversely to the direction of current flow through the resistance element, i.e., so that the current flowing through the resistance element will flow from mass to mass. SEE OR SEARCH THIS CLASS, SUBCLASS: 52, for resistors with heat dissipating projections, and having granular powdered or transversely stacked elements. 99+, for mechanically variable resistors including surfaces pressed together for adjustment purposes, e.g., compressible type; and subclass 115 for such resistors generally whose elements are in piled or stacked layers. 204+, for resistors generally whose elements are piled or stacked between terminals. 223+, for resistors having granular or powdered elements.

55	With cooling liquid circulation
	This subclass is indented under subclass 53.  Subject matter including means for conveying or facilitating the conveyance of liquid to or from the resistance element or terminals, or to structure in heat conducting relation to the element to carry away at least part of the heat produced by the element or terminals by motion of the liquid. (1) Note. A mere heat conducting liquid without motion or circulation of the liquid is not classified here, but in subclass 231 below. Where structure is claimed for controlling or directing the heat to the liquid, or controlling or utilizing the heated liquid for heating purposes as opposed to mere dissipation of the heat, classification is elsewhere (see search notes below). See also (1) Note under subclass 53 above. SEE OR SEARCH THIS CLASS, SUBCLASS: 57, for resistors with vented or ventilating casing or housings. 231, for resistors generally incased in a liquid. See also (1) Note above. SEE OR SEARCH CLASS: 165,  Heat Exchange,   subclasses 104.19+ for a residual system exchanging heat through a recycling fluid. 219,  Electric Heating,   subclasses 280+ for electric fluid heaters. See also (1) Note above. 333,  Wave Transmission Lines and Networks,   subclass 22 for dissipating terminations for long lines involving a liquid coolant.

56	Liquid resistance element circulates
	This subclass is indented under subclass 55.  Subject matter wherein the circulating or moving liquid is also the resistance element, and by such circulation or motion the element is cooled or cools itself. SEE OR SEARCH THIS CLASS, SUBCLASS: 222, for resistors generally with liquid elements. SEE OR SEARCH CLASS: 219,  Electric Heating,   subclasses 284+ for electric fluid heaters, wherein the fluid is heated by the passage of electric current directly therethrough.

57	Vented or ventilating casing or housing
	This subclass is indented under subclass 53.  Subject matter including a casing or housing of solid material which substantially entirely encloses the resistance element, the casing or housing having openings therein joining the resistance element with the surrounding medium to permit circulation of air or other gases to and from the resistance element. (1) Note. The subject matter here is restricted to casings with vents or other openings transmitting air or other gases. Subclasses 55+ provides for resistors with casings and liquid cooling. Further the air or gas must be free to circulate for classification here. Subclasses 234+ provides for an incased, embedded or housed resistor with a gaseous or vacuum spacing between the element and casing or housing without the ventilation or cooling. The ventilation may be forced as by a fan as well as naturally for classification here. Subclasses 226+ below provides for resistors generally with casings or housings which transmit heat through the material to the casing or housing. A mere open ended sleeve surrounding the resistance element is not sufficient to constitute a vented casing for classification here, but rather is classified in subclass 53 above, if air circulation is present. SEE OR SEARCH THIS CLASS, SUBCLASS: 51+, for resistors with heat dissipating projections, e.g., vanes. 53+, for resistors with ventilating passages or spaces generally. See also (1) Note above. 55+, for incased resistors with a liquid cooling medium. See also (1) Note above. 234+, for incased, embedded or housed resistors generally with a gaseous or vacuum spacing between the element and the casing or housing. See also (1) Note above. 277, for resistors with protecting structure such as guards, screens, and mechanical shields. SEE OR SEARCH CLASS: 174,  Electricity: Conductors and Insulators,   subclass 16.1 for a mere housing or casing for an electrical device with means to provide for ventilation of the interior of the casing. 219,  Electric Heating,   subclasses 280+ for fluid resistance heaters. See also (1) Note under subclass 53 above. 312,  Supports: Cabinet Structure,   subclass 213 for enclosures with ventilated openings not otherwise classifiable. 336,  Inductor Devices,   subclass 59 for inductors with vented casings. 454,  Ventilation,   appropriate subclasses, for ventilating structure such as cowls, hoods and louvers.

58	Ventilated helical or zigzag element
	This subclass is indented under subclass 53.  Subject matter wherein the resistor is of zigzag or helical type as defined in subclasses 283 and 296 respectively below, together with structure which transmits or facilitates the transmission of air or other gases to and into contact with the resistance element for cooling purposes. (1) Note. The ventilating structure may be air passages or a particular spacing of the resistance element or parts thereof to facilitate air cooling. For classification here, the resistance element must be directly ventilated. A mere passage in a core or support for cooling purposes and not leading directly to the element, is not classified here, but in such subclasses as 53 and 55+, above. SEE OR SEARCH THIS CLASS, SUBCLASS: 53, for resistors with ventilating passages or spaces generally. See also (1) Note above. 57, for a zigzag or helical resistor with a ventilating casing or housing, the zigzag or helical resistor also being ventilated. 283+, for resistors with zigzag or sinuous resistance elements generally. 296, for resistors with helical or wound resistance elements generally.

59	WITH HEAT-STORING
	This subclass is indented under the class definition.  Subject matter wherein the resistor includes or is combined with a mass of material which is adapted to absorb and retain significantly well the heat produced by the resistance element, or the heat existing in the medium surrounding the resistor, or structure which is peculiarly adapted to support such a mass in or on the resistor. (1) Note. Examples of subject matter here are resistors having a surrounding iron mass for storing the resistor heat, or resistors having containers for storing ice. SEE OR SEARCH THIS CLASS, SUBCLASS: 53+, for a resistor with a circulating gas cooling medium. 55+, for a resistor with a circulating liquid cooling medium. SEE OR SEARCH CLASS: 126,  Stoves and Furnaces,   subclass 400 for heat accumulators.

60	WITH CAPACITY-REDUCING
	This subclass is indented under the class definition.  Subject matter wherein the resistor includes distinct structure or arrangement of parts which reduce or eliminate the resistor capacity or the effect of the resistor capacity in the resistor. (1) Note. For classification here the definite structure or arrangement of parts must be for reducing or eliminating the inherent capacity of the resistor as opposed to some type of electric shielding to reduce the effect of external capacity (e.g., hand capacity) on the resistor. Resistors having shielding to reduce or eliminate external capacity effects are classified in 64+ below. SEE OR SEARCH THIS CLASS, SUBCLASS: 61, for resistors having structure to reduce or eliminate inductance or the effect of inductance on the resistance. 64+, for resistors having electrical shielding. See also (1) Note above. 334, for resistors electrically connected to other electric devices, and not elsewhere classified. SEE OR SEARCH CLASS: 361,  Electricity: Electrical Systems and Devices,   subclasses 271+ for capacitors combined with some other type of subject matter.

61	WITH INDUCTANCE-REDUCING
	This subclass is indented under the class definition.  Subject matter wherein the resistor includes distinct structure or arrangement of parts which reduce or eliminate the resistor inductance or the effect of the resistor inductance in the resistor. (1) Note. For classification here definite structure or arrangement of parts must be present to reduce or eliminate the inductance. A resistor with a coated, granular, or straight rod resistance element, for example, which inherently has a relatively low inductance, is not classified here, but in such subclasses as 223+, 308 and 322+, respectively. Further the structure or arrangement must be for reducing or eliminating the inherent inductance in the resistor as opposed to some type of electric shielding to reduce the effect of some external inductance. Subclasses 64+ below provides for resistors with electrical shields. SEE OR SEARCH THIS CLASS, SUBCLASS: 60, for resistors with capacity reducing means. 64, for resistors with electrical shields. SEE OR SEARCH CLASS: 174,  Electricity: Conductors and Insulators,   subclasses 32+ for electrical conductors with anti-inductive structure; and especially subclasses 33+ for conductor transposition. 307,  Electrical Transmission or Interconnection Systems,   subclasses 89+ for anti-inductive means to prevent or modify the coupling between electrical systems. 336,  Inductor Devices,   for inductor devices of the passive type.

62	Helical or wound element
	This subclass is indented under subclass 61.  Subject matter wherein the resistor includes an elongated resistance element formed as two or more continuous closed coils or loops as a spiral, helix, or toroidal winding as defined in subclass 296 below, together with additional structure or arrangement of the coils or loops for reducing or eliminating the inductance or the effect thereof of the coils or loops. SEE OR SEARCH THIS CLASS, SUBCLASS: 296+, for resistors generally with helical or wound resistance elements.

63	Bifilar
	This subclass is indented under subclass 62.  Subject matter, wherein the helical or wound resistance element is doubled on itself, the bight being at one end of the winding and the doubled portions of the resistance element being disposed side by side in parallel and extending towards the other end in a helical or wound pattern.

64	WITH ELECTRICAL SHIELD
	This subclass is indented under the class definition.  Subject matter including a barrier or screen for shielding at least a part of the resistor device from external electrical, magnetic, or electro-magnetic fields, or for protecting parts of the device from such fields originating in another part of the device, of for preventing the resistor device from emanating such fields or waves containing such fields. (1) Note. A fixed resistor with a casing or housing claimed as an electrical shield or equivalent terminology is classified here, and not in subclasses 226+ below. SEE OR SEARCH THIS CLASS, SUBCLASS: 60, for resistors having means to reduce or eliminate capacity of the effect thereof within the resistor. 61+, for resistors having means to reduce or eliminate inductance or the effect thereof within the resistor. 266+, for resistors generally with casings or housings not limited by claimed subject matter to electric shielding. See also (1) Note above. SEE OR SEARCH CLASS: 174,  Electricity: Conductors and Insulators,   subclasses 350 through 397for electrically shielded electrical conductors and insulators; or electrical shields or screens not classifiable in other main classes. See also the Search Notes under this subclass. 334,  Tuners,   subclass 85 for tuners with electric and/or magnetic shielding or housing means. 336,  Inductor Devices,   subclasses 84+ for inductor devices with electric and/or magnetic shielding means.

65	Mechanically variable resistor
	This subclass is indented under subclass 64.  Subject matter wherein the resistor is of the mechanically variable type as defined in subclass 68 below. SEE OR SEARCH THIS CLASS, SUBCLASS: 68+, for mechanically variable resistors generally. 184, for mechanically variable resistors whose contact slides along in contact with the element together with a casing or housing, and not limited by claimed subject matter to electrical shielding. 199, for a mechanically variable resistor generally, with a casing or housing not limited by claimed subject matter to electrical shielding. SEE OR SEARCH CLASS: 336,  Inductor Devices,   subclass 87 for adjustable inductive devices with electric and/or magnetic shielding means.

66	IGNITION INTERFERENCE SUPPRESSOR TYPE
	This subclass is indented under the class definition.  Resistors which when inserted in an ignition circuit are particularly well adapted for the suppression of undesired currents in the circuits, which would otherwise produce electrical disturbances, and are characterized by having usually a heavy ceramic insulation casing, a heavy granular bonded mixture as the material for the resistance element incased in the insulating casing, and diverse quick detachable terminals as one being the plug type and the other being of the socket type. (1) Note. For classification here the background or use must be an ignition circuit. SEE OR SEARCH THIS CLASS, SUBCLASS: 64+, for resistors with electrical shields. SEE OR SEARCH CLASS: 123,  Internal-Combustion Engines,   subclass 148 for high tension ignition circuits for internal combustion engines.

67	WITH DIVERSE NONELECTRICAL DEVICE (E.G., MECHANICAL OR CHEMICAL)
	This subclass is indented under the class definition.  Subject matter wherein the resistor is combined with some other nonelectrical device or structure, for example, of a mechanical or chemical type, having an added purpose or independent utility other than to perfect the resistor, and not otherwise classifiable. SEE OR SEARCH THIS CLASS, SUBCLASS: 2+, for strain gauge type resistors together with the structure or device broadly wherein the strain is to be determined. 13+, for resistors with a condition sensing actuator; especially subclass 32 for a resistor actuated by a compass; subclass 33 for a resistor actuated by a float; and subclass 37 for a resistor actuated by vehicle tire inflation pressure. 50, for a resistor mounted on wheels or vehicles. 277, for a resistor with protecting structure spaced from the element or terminal. 315+, for a resistor with mounting or supporting means. 334, for resistors electrically connected to other electrical devices, and not otherwise classifiable. SEE OR SEARCH CLASS: 219,  Electric Heating,   subclasses 50+ for electrical resistance heaters.

68	MECHANICALLY VARIABLE (E.G., RHEOSTAT)
	This subclass is indented under the class definition.  Subject matter including a resistance element together with structure for changing a dimension of the resistance element or the effective portion of the resistance element between terminals, as a change in the cross-sectional area or an increase in length of the portion of the resistance element between the terminals; and/or wherein the resistance element is readily adapted or at least adapted for such change in a dimension; or including structure permitting a ready change in the position or point of electrical connection of one or more of the terminals on the resistance element to cause a different portion of the element to be in electrical circuit between the terminals; or including conducting structure which adjustably short-circuits a portion of the resistance element between terminals; or including switching structure which alters the resistance portion of the resistance element in electrical circuit between terminals or which changes the circuit relationship of the resistance element and other resistance elements or which permits the resistance elements to be changed in or removed from the circuit; the result in any of the above being a change in the resistance value between the resistance terminals or the terminals in the circuit including the resistance element; or wherein the resistance element is adapted for or combined with structure for mechanically changing in some manner the resistance element or the combination including the resistance element; or including any other means or adaption of the resistance element or elements for mechanically changing an arrangement of or effecting a mechanical change in the resistance element or elements to achieve the above mentioned result. (1) Note. The change in resistance value as stated above is the result of or involves some mechanical change or adjustment on or in the resistance element or terminals, which includes switching of the terminals. The resistance value may be changed otherwise as by change in temperature, electric current therethrough, or voltage applied thereof. This subject matter is classified above, a field of search for such subject matter being given below. SEE OR SEARCH THIS CLASS, SUBCLASS: 1, for coherer type resistors. 2+, for strain gauge type resistors. 7+, for resistors whose resistance value is temperature compensated. 12, for resistors which are actuated by a magnet through a housing or partition. 13+, for mechanically adjustable resistors which are combined with structure which senses a change in a condition and converts this change into a mechanical adjustment which is applied to the mechanically adjustable resistor to effect a mechanical adjustment therein with a resulting change in resistance value; or for resistors which have the property of changing their resistance value in response to changes in associated conditions to which the resistors are subjected, such as subclasses 15+, for photoconductive resistors; subclasses 20+, for current and/or voltage responsive resistors; subclasses 25+, for resistors responsive to ambient temperature; subclass 32, for resistors responsive to a magnetic field or compass; subclass 33, for resistors with a float actuator; subclasses 34+ for resistors with gas, vapor, or moisture absorbing or collecting; subclasses 36+ for fluid or gas pressure actuated resistors; subclasses 43+ for resistors gravity stabilized or with an inertia actuator; and subclass 47 for force actuated resistors. 60, for resistors with capacitance reducing means. 61+, for resistors with inductance reducing means. 64+, for resistors with electrical shielding. 66, for ignition interference suppressor type resistors. SEE OR SEARCH CLASS: 200,  Electricity: Circuit Makers and Breakers,   for electrical circuit makers and breakers, per se. 323,  Electricity: Power Supply or Regulation Systems,   subclasses 293+ and subclasses 364+ for regulation systems including a resistor and subclasses 340+ for regulation systems including tap changing. 329,  Demodulators,   subclass 371 for a coherer type amplitude modulation demodulator. 333,  Wave Transmission Lines and Networks,   subclass 81 for attenuators, which may be variable. 336,  Inductor Devices,   appropriate subclasses, for adjustable inductor devices. 361,  Electricity: Electrical Systems and Devices,   subclasses 277+ for variable capacitors. 439,  Electrical Connectors,   appropriate subclasses, for electrical connectors. 455,  Telecommunications,   subclasses 120+ and 150.1+ for radio transmitter and receiver tuners.

69	Musical instrument playing key actuated
	This subclass is indented under subclass 68.  Subject matter wherein a musical instrument playing key (usually an organ key) is linked with the mechanically adjustable or variable part of the resistor to change the resistance value in accordance with the depression of the key. SEE OR SEARCH THIS CLASS, SUBCLASS: 153, for mechanically variable resistors operated by a pedal or treadle. SEE OR SEARCH CLASS: 84,  Music,   subclasses 1.01+ for electrical tone generation and music instruments with electric translating devices.

70	In or on lamp socket
	This subclass is indented under subclass 68.  Subject matter including a lamp socket together with a resistor as defined in subclass 68 positioned within the socket, or directly on and in engagement with the surface of the socket, and in circuit with the terminal or terminals of the socket. (1) Note. The lamp socket to receive the lamp is usually of the type classifiable as such in Class 439, Electrical Connectors. Usually when structure in addition to that classified in Class 439 is recited, as relating to Class 240, Illumination, or to Class 340, Communications: Electrical, classification is not in this subclass (70) or in Class 439, but in the more comprehensive subclass. See the Search Notes under Classes 313 and 439 for a statement of the classification lines between Class 439 and other classes relating to lamp bases and sockets. The resistor must be intimate relationship with the socket as being contained therein or in a surface recess for classification in this subclass (70). A mere electrical connection between the resistor and the socket or a remote mounting of the resistor on the socket is not sufficient for classification here. Subclasses 315+, provides for resistors with mounting or supporting means. SEE OR SEARCH THIS CLASS, SUBCLASS: 184, and 199, for mechanically variable resistors in housings generally. 215, for resistors generally with a switch. 219, for resistors generally mounted in or on a lamp socket. See also the Search Notes under this subclass for a more extended field of search for this subject matter. 220, for resistors generally in a detachable electrical connector.

71	Resistor surfaces pressed together (e.g., compressible type)
	This subclass is indented under subclass 70.  Subject matter wherein the resistor includes (1) two or more separate and distinct masses, including grains, of resistance material, or (2) a distinct and separate mass of resistance material and a mass of conductive material are in exterior surface engagement with one another, together with means for varying the surface engagement pressure to vary the contact resistance between the engaging surfaces, i.e., the resistor is of the type defined in subclass 99 below. SEE OR SEARCH THIS CLASS, SUBCLASS: 99+, for mechanically variable resistors whose surfaces are pressed together generally. See also the Search Notes under this subclass for field of search for this subject matter.

72	Resistor with intervening connector between contact and element (e.g., taps)
	This subclass is indented under subclass 70.  Subject matter wherein the resistor, a plurality of otherwise electrically separate conducting structures, are each electrically connected to an elongated resistance element along its length, and a terminal movable among the conducting structures to constitute a contact on such structures as defined in subclass 185 below. SEE OR SEARCH THIS CLASS, SUBCLASS: 185+, for mechanically variable resistors generally with an intervening connector between the contact and element, e.g., taps. See also the Search Notes under this subclass for a field of search for resistors of this type.

73	Resistor with contact angularly slidable on element
	This subclass is indented under subclass 70.  Subject matter wherein the resistor, a movable contact, pivots about an axis to slide in a circular path along a resistance element as defined in subclasses 162+ below. SEE OR SEARCH THIS CLASS, SUBCLASS: 162+, for mechanically variable resistors where the contact is angularly slidable on a resistance element. See also the Search Notes under this subclass for a field of search for resistors of this type.

74	Resistor with contact rectilinearly slidable on element
	This subclass is indented under subclass 70.  Subject matter wherein in the resistor, the contact terminal, moves in a straight path over or along a resistance element, the contact terminal remaining in contact with the element as it slides along as defined in subclass 176 below. SEE OR SEARCH THIS CLASS, SUBCLASS: 176, for mechanically variable resistors wherein the contact is rectilinearly slidable over the resistance element. See also the Search Notes under this subclass for a field of search for resistors of this type.

75	With resistor cleaner
	This subclass is indented under subclass 68.  Subject matter including structure, such as a wiper, for removing dirt or other material from the resistor, as from the contacting surfaces of the resistance element or the contact movable thereon.

76	Interchangeable resistors of different resistance value
	This subclass is indented under subclass 68.  Subject matter including two or more physically similar resistors of different resistance values together with means effecting or permitting a change or substitution of one resistor for the other in an associated electrical circuit, i.e., both terminals of one resistor are separable from the electrical circuit and the terminals of the other resistor are connected in the electrical circuit in a corresponding position. SEE OR SEARCH THIS CLASS, SUBCLASS: 77, for plug boxes. 185+, for mechanically variable resistors of the tap type. 200+, for mechanically variable resistors generally including a switch for effecting a change in the resistance value.

77	Plug boxes
	This subclass is indented under subclass 68.  Subject matter including a base or panel having a single resistor or a plurality of resistors mounted thereon or in a box or housing, the panel constituting a cover therefor, together with terminals mounted on the panel and electrically connected along the length of a single resistor or to the ends of the plurality of resistors, the terminals having openings therein or providing openings; and including also terminal plugs adapted to be removably inserted in the openings to short-circuit respective resistors or portions thereof, or to connect the resistors in series or parallel. SEE OR SEARCH THIS CLASS, SUBCLASS: 92+, for mechanically variable resistors including means adjustably short-circuiting the resistance element. 185+, for tap type mechanically variable resistors. 200+, for a mechanically adjustable resistor combined with a switch. 215, for resistors generally combined with switches. SEE OR SEARCH CLASS: 174,  Electricity: Conductors and Insulators,   subclasses 50+ for boxes and housings generally for electrical devices. 361,  Electricity: Electrical Systems and Devices,   subclasses 627+ for distribution or control panel board.

78	With current reversing (e.g., reversing rheostat)
	This subclass is indented under subclass 68.  Subject matter wherein a resistor or plurality of resistors as there defined is combined with or includes an electric switch in a common electric circuit, the switch being effective to reverse the electric current at the output terminals of the resistor with respect to the current applied at the input terminals. (1) Note. Usually the resistor and switch have a common actuator. SEE OR SEARCH THIS CLASS, SUBCLASS: 200+, for mechanically adjustable or variable resistors combined with switches in general. See the Search Notes under this subclass for a more extended field of search for a variable resistor combined with a switch. 215, for a fixed resistor combined with a switch. See also the Search Notes under this subclass for a more extended field of search for this combination. SEE OR SEARCH CLASS: 318,  Electricity: Motive Power Systems,   subclasses 293+ and 300 for motor reversing systems which involve reversal of the armature or field current.

79	With element winding and/or unwinding
	This subclass is indented under subclass 68.  Subject matter wherein the resistance element is wound on a core, and is adapted to be unwound therefrom as on a second core to change the value of the resistance between terminals. (1) Note. Examples of subject matter here include a resistor whose element is wound from an insulating core to a conducting core, the conducting core short-circuiting the portion of the resistance element wound thereon; and a resistor whose element is wound between two cores with a contact slidably engaging the portion of the element between cores. SEE OR SEARCH THIS CLASS, SUBCLASS: 150+, for variable resistors in which the resistance element moves. 296+, for helical or wound resistors generally. SEE OR SEARCH CLASS: 242,  Winding, Tensioning, or Guiding,   subclasses 370+ for a general use reeling device which unwinds and rewinds the same material. 334,  Tuners,   subclass 38 for a tuner having a reactance element which is adapted to be wound or unwound from a core or support. 336,  Inductor Devices,   subclass 15 for inductor devices with coil winding and/or unwinding.

80	Liquid resistance element
	This subclass is indented under subclass 68.  Subject matter wherein the resistance element is a liquid, the resistance value of the resistor being changed as by modifying the dimensions of the element or the spacing between terminals or electrodes. SEE OR SEARCH THIS CLASS, SUBCLASS: 27, for a resistor with a liquid element whose resistance value is responsive to ambient temperature; subclass 38 for such resistors whose resistance value is responsive to fluid or gas pressure; and subclass 44 for such resistors which are gravity stabilized or with an inertia actuator. 56, for a resistor whose element constitutes a circulating cooling medium. 88, for penetrating type resistors with a powdered resistance element. 100, for compressible type resistors with a granular resistance element. 114+, for deformable variable resistors. 156, for variable resistors having a liquid contact movable over the resistance element. 222, for a resistor generally with a liquid element. 223, for a resistor generally with a granular or powdered element. SEE OR SEARCH CLASS: 323,  Electricity: Power Supply or Regulation Systems,   subclass 296 for regulation systems having a liquid resistor. 329,  Demodulators,   appropriate subclasses for demodulator with liquid element.

81	Electrode separable from liquid element for switching
	This subclass is indented under subclass 80.  Subject matter wherein one of the terminals or electrodes is removable from the liquid resistance element, as by raising the electrode from the liquid element or by lowering the level of the liquid element from the electrode, thus to make and break the circuit between the liquid element and the electrode. SEE OR SEARCH THIS CLASS, SUBCLASS: 173, for a resistor whose contact is angularly slidable on the resistance element and separable from the element; and subclass 178 for such resistors whose contacts are rectilinearly slidable. 198, for a mechanically variable resistor with a switch actuated by the resistor actuator.

82	Adjustable insulating barrier between electrodes
	This subclass is indented under subclass 80.  Subject matter including an insulating barrier or curtain which is positioned transversely to the current path through the liquid element between the electrodes, the barrier or curtain being adjustable in and out of this current path to change the effective length of the current path between the electrodes and/or the effective cross-sectional area of the path between the electrodes. SEE OR SEARCH THIS CLASS, SUBCLASS: 114, for deformable resistors generally.

83	Variable electrode separation
	This subclass is indented under subclass 80.  Subject matter wherein one of the terminals or electrodes in the liquid element is movable with respect to another electrode or terminal in the element to effect a change in the distance between the electrodes to change the resistance value between the terminals. (1) Note. For classification here there must be a change in the physical spacing of the electrodes. A mere change in the effective spacing of the electrodes in the resistance element as by adjusting the submersion of tapered electrodes in the liquid resistor is not classified here (see search note below). SEE OR SEARCH THIS CLASS, SUBCLASS: 86, for a liquid resistor whose liquid level is adjustable on the electrodes. See also (1) Note above. 87+, for a mechanically variable resistor whose contact is adjustably inserted into a nonliquid resistance element. 137, for resistors wherein a plurality of contacts are movable over a single resistance element.

84	Plural ganged electrodes
	This subclass is indented under subclass 83.  Subject matter wherein a plurality of resistors as there defined have an electrode of one mechanically linked with a corresponding electrode of another so that the two electrodes move in unison through the liquid element of the respective resistors; or wherein a single resistor as there defined includes a plurality of electrodes which are mechanically linked together to move in unison through the liquid element of the resistor toward and away from another electrode of the resistor. SEE OR SEARCH THIS CLASS, SUBCLASS: 130+, plural ganged resistors of the type where a contact moves over the length of the resistance element.

85	Electrode rotatable
	This subclass is indented under subclass 83.  Subject matter wherein at least one of the electrodes is rotatable to effect the change in distance through the liquid element to another electrode. SEE OR SEARCH THIS CLASS, SUBCLASS: 32, for a resistor whose value changes in response to a magnetic field.

86	Level of liquid element adjustable on electrodes (e.g., electrodes move up and down in element)
	This subclass is indented under subclass 80.  Subject matter including structure for raising or lowering the level of the liquid resistance element with respect to the electrodes inserted in the liquid element; or including structure for moving or permitting movement of the electrodes up and down in the liquid element. (1) Note. This subclass includes resistors whose effective electrical length between electrodes is varied by adjusting the submersion of electrodes in a liquid. See search notes below. SEE OR SEARCH THIS CLASS, SUBCLASS: 33, for float actuated resistors. 55+, for resistors with cooling liquid circulation. 83+, for resistors whose electrodes are relatively movable in the liquid element to change the distance between the electrodes through the element, and see the (1) note under that definition. SEE OR SEARCH CLASS: 323,  Electricity: Power Supply or Regulation Systems,   subclass 296 for regulation systems having a liquid resistor.

87	Contact adjustably inserted into resistance element (e.g., penetrating type)
	This subclass is indented under subclass 68.  Subject matter wherein a contact extends into the resistance element and is movable therein to vary the spacing through this resistance element between this contact and another contact, thus to vary the resistance value between the contacts. SEE OR SEARCH THIS CLASS, SUBCLASS: 80+, for mechanically variable liquid resistors. 92+, for mechanically variable resistors whose resistance elements are adjustably short-circuited. 322, for resistors with a driven or pressed terminal. 331, for resistors generally whose element surrounds one of the terminal.

88	Powdered element
	This subclass is indented under subclass 87.  Subject matter wherein the resistance element is granular or powdered, the contact usually being formed as a pin or other elongated object to penetrate into the powdered or granular element. SEE OR SEARCH THIS CLASS, SUBCLASS: 100, for compressible type granular resistors. 223+, for resistors generally with granular or powdered elements.

89	Mathematical function (e.g., sine-cosine potentiometer)
	This subclass is indented under subclass 68.  Subject matter wherein, in the variable resistor, a definite mathematical relationship exists between movement of the resistor actuating means and the value of the resistance appearing across the resistor terminals. (1) Note. Examples of the relationship appearing in this subclass are sinusoidal and logarithmic. A mere tapered variable resistor is not classified here (see search this class, subclass notes below), unless the definite mathematic relationship that the taper produces is recited in the specification or claims. SEE OR SEARCH THIS CLASS, SUBCLASS: 135, for mechanically variable resistors with zero setting or phasing. 138+, for mechanically variable resistors having a tapered element. See also (1) Note, above. 217+, for tapered resistors generally. SEE OR SEARCH CLASS: 235,  Registers,   subclasses 61+ for resistors having a mathematical characteristic in a calculator. 323,  Electricity: Power Supply or Regulation Systems,   subclasses 298 and 354 for periodically varied impedance systems. 333,  Wave Transmission Lines and Networks,   subclass 81 for attenuators. 336,  Inductor Devices,   subclass 224 for inductors having nonuniformly spaced turns. See also the Search Notes thereunder for a more extensive search for this subject matter. 708,  Electrical Computers: Arithmetic Processing and Calculating,   subclasses 800+ for resistors having a mathematical characteristic in an electrical calculator.

90	With slab or card-type resistance element
	This subclass is indented under subclass 89.  Subject matter wherein the resistance element is formed as a surface having significant width as well as length, together with a contactor relatively movable not only lengthwise but crosswise over the surface of the element. SEE OR SEARCH THIS CLASS, SUBCLASS: 116, for electric motor driven resistors. SEE OR SEARCH CLASS: 363,  Electric Power Conversion Systems,   subclass 140 for impedance type converters.

91	With mechanical converter
	This subclass is indented under subclass 89.  Subject matter including a mechanical linkage in or an arrangement of the resistor actuator producing some peculiar operating characteristic to contribute to the mathematical relationship. (1) Note. Examples of subject matter present here include a cam and follower linkage or an eccentric mounted contact movable over an annular resistance element. SEE OR SEARCH THIS CLASS, SUBCLASS: 116, for electric motor driven resistors. SEE OR SEARCH CLASS: 363,  Electric Power Conversion Systems,   subclass 140 for impedance type converters.

92	Resistance element adjustably short-circuited
	This subclass is indented under subclass 68.  Subject matter wherein the resistor includes an elongated element together with conductive structure connected at spaced points being adjustable along the length of the element; or wherein the resistance element is bent upon itself so that two points along the length of the element adjustably contact electrically to effectively eliminate electrically the portion between the two points from the electric path through the resistor, i.e., a variable portion of the resistance element is shunted; or wherein a conducting mass such as a liquid is adjustably connected along the length of the element. SEE OR SEARCH THIS CLASS, SUBCLASS: 77, for adjustable resistors of the plug box type. 79, for mechanically variable resistors with element winding and/or unwinding. 87+, for adjustable resistors wherein a contact adjustably penetrates into the element. 118+, for mechanically variable resistors wherein a contact moves over the length of the resistance element; and especially subclass 120, for such resistors whose element is adjustably shunted by an additional resistor; and subclasses 122+, for such resistors with coarse and fine resistance elements. SEE OR SEARCH CLASS: 323,  Electricity: Power Supply or Regulation Systems,   subclass 353 , for regulation systems.

93	Compressible spring type
	This subclass is indented under subclass 92.  Subject matter in which the resistance element is formed as a compressible spring (usually helical), the convolutions of the spring coming into contact upon compression to short-circuit at least a portion of the length of the resistance element. SEE OR SEARCH THIS CLASS, SUBCLASS: 99+, for compressible type variable resistors generally. 114+, for mechanically variable resistors whose elements are deformable.

94	Liquid contact
	This subclass is indented under subclass 92.  Subject matter including a conducting liquid as the resistance element short circuiting means, a portion of the elongated resistance element being adjustably inserted in the conducting liquid to short-circuit the portion of the element so inserted, or the conducting liquid being adjustable along any intervening structure, if present, such as taps. SEE OR SEARCH THIS CLASS, SUBCLASS: 80, for a mechanically variable resistor whose element is a liquid. 151, for a mechanically variable resistor whose element moves with reference to a liquid contact. 156, for a mechanically variable resistor having a liquid contact adjustable along the length of the resistance element. 222, for liquid resistors generally.

95	With intervening structure between element and short-circuiting means (e.g., taps)
	This subclass is indented under subclass 92.  Subject matter wherein a plurality of otherwise electrically separate conducting structures are each electrically connected to the resistance element along its length, the short circuiting structure being adjustably connected between these conducting structures. (1) Note. The separate conducting structures themselves may be pressed into contact with one another to form in themselves the short circuiting means. SEE OR SEARCH THIS CLASS, SUBCLASS: 94, for a tap type resistor whose element is adjustably short-circuited by a conducting liquid. 185, for variable resistors of the tap type. 198, and 200+, for variable resistors with switches.

96	Spring contact strip progressively pressed along element
	This subclass is indented under subclass 92.  Subject matter wherein a flexible elongated conductor has an end electrically connected to a terminal of the resistance element or to the element itself at a point along its length, the conductor being adapted to be pressed into engagement with and along the length of the elongated conductor, the engaging portion extending from the connection to the resistance element and progressively increasing as the strip is pressed into contact with the element, whereby an adjustable length of the element is shunted by the conductor. (1) Note. Usually the flexible contact or the element has a curved surface to space adjacent portions of the contact and element until pressed into engagement. SEE OR SEARCH THIS CLASS, SUBCLASS: 95, for a tap type resistor wherein a flexible short circuiting contact strip progressively engages along the taps of a resistance element. 154, for a mechanically variable resistor where a flexible conductive strip separates the resistance element and the contact movable along the element. 155, for a variable resistor with a contact which rocks along the resistance element. 157, for a variable resistor with a contact which rolls along the element.

97	Unitary movable contact electrically bridges resistance portions
	This subclass is indented under subclass 92.  Subject matter wherein the resistance element has portions extending in parallel spaced relationship and a conducting bridge extending between the parallel portions being movable lengthwise therealong. (1) Note. In this subclass the bridging element shorts a single resistance element, while in subclasses 125+ a plurality of resistance elements are connected by a unitary movable bridge. SEE OR SEARCH THIS CLASS, SUBCLASS: 125+, for variable resistors wherein a plurality of resistance elements are bridged by a unitary movable contact. See also (1) Note above.

98	With motion or vibration damping means (e.g., dashpots)
	This subclass is indented under subclass 68.  Subject matter including structure associated with the mechanically adjustable portion of the resistor for retarding the adjustment of the resistor over at least a portion of the adjustment range, or for eliminating or reducing vibration. (1) Note. Examples of motion damping means are fans, speed responsive brakes, or damping liquids. The subject matter of this subclass includes structure for slowing down the desired mechanical adjustments of the resistor as to prevent hunting of the resistor. Structure for eliminating or offsetting or otherwise controlling the effect of vibration in photo-conductive resistors is in subclass 16 above, while subclasses 315+ provides for resistors generally with anti-vibration supports. SEE OR SEARCH THIS CLASS, SUBCLASS: 16, for photo-conductive resistors with vibration control. See also (1) Note above. 43+, for resistors responsive to a gravity stabilized or inertia device. 80+, for mechanically variable resistors with a liquid element. 171, for variable resistors with a contact slidable on the resistance element, the contact having plural element engaging portions, which may reduce the effect of vibration. 315+, for resistors generally with anti-vibration supports. See also (1) Note above. SEE OR SEARCH CLASS: 188,  Brakes,   subclass 86 for fluid and mechanical internal resistance brakes including dashpots. 200,  Electricity: Circuit Makers and Breakers,   subclass 34 for electrical switches with dashpots.

99	Surfaces pressed together (e.g., compressible type)
	This subclass is indented under subclass 68.  Subject matter wherein (1) two or more separate and distinct masses, including grains, of resistance material or (2) a distinct and separate mass of resistance material and a mass of conductive material are in exterior surface engagement with one another, together with means for varying the surface engagement pressure to vary the contact resistance between the engaging surfaces. (1) Note. The masses may be layers of solids, or granular, or fibrous such as steel wool, or coated materials. The conducting mass may be a terminal. (2) Note. In this subclass the resistance value is varied by the change in contact pressure between the two masses. While in subclasses 2+ and 114+ the cross section area or length of the element itself may be changed by compression to vary the resistance value. SEE OR SEARCH THIS CLASS, SUBCLASS: 1, for coherer type resistors. 47+, for force actuated resistors. 51+, for resistors with heat dissipating projections, such as vanes. 70+, for a lamp socket having a compressible type resistor therein or thereon. 93, for a compressible spring type variable resistor whose element is adjustably short-circuited. 114+, for a mechanically variable resistor whose element is deformable to vary the resistance value. See also (2) Note above. 204+, for fixed resistance elements formed of layers piled or stacked between terminals. SEE OR SEARCH CLASS: 323,  Electricity: Power Supply or Regulation Systems,   subclass 295 for regulation systems including a pressure variable resistor.

100	Granular
	This subclass is indented under subclass 99.  Subject matter wherein at least one of the resistance masses is granular or powdered in form. SEE OR SEARCH THIS CLASS, SUBCLASS: 1, for coherer type resistors. 88, for penetrating type resistors having granular resistance elements. 199, for a mechanically adjustable resistor generally with a casing or housing. 223+, for granular or powdered resistors generally. SEE OR SEARCH CLASS: 330,  Amplifiers,   subclass 61 for carbon microphone type amplifiers.

101	Pile type
	This subclass is indented under subclass 99.  Subject matter wherein two or more masses of resistance material are formed as wafers or discs and are disposed on top of one another to form a pile, the engagement pressure being applied axially along the pile. SEE OR SEARCH THIS CLASS, SUBCLASS: 115, for a mechanically variable resistor generally whose resistance element is formed as a pile.

102	With contactor moving along pile
	This subclass is indented under subclass 101.  Subject matter together with a contact which is adjustable along the length of the pile to permit a varying portion of the pile to be connected in the circuit associated with the contact. SEE OR SEARCH THIS CLASS, SUBCLASS: 48, for plural separate diverse resistors. 118+, for a mechanically variable resistor generally having a contact electrically adjustable over the length of the resistance element.

103	With electromagnetic operator (e.g., electric motor)
	This subclass is indented under subclass 101.  Subject matter including an electromechanical transducer such as an electric motor or a magnetic relay, the moving part such as the armature of the transducer being mechanically linked with the piles to compress or to release the pressure on the piles upon application of electric energy to the transducer. SEE OR SEARCH THIS CLASS, SUBCLASS: 116, for mechanically variable resistors generally operated by an electric motor or relay.

104	Force applied at both ends of pile
	This subclass is indented under subclass 103.  Subject matter including two electromagnetic operators each applying a positive compressive or releasing force to a respective end of the pile, or a linkage connected with a single electromagnetic operator for applying a positive compressive or releasing force to both ends of the pile. (1) Note. For classification here an actual force must be applied to both ends of the pile. A mere abutment at one end which exerts a holding force in opposition to the force applied at the other end by the relay or motor is not sufficient for classification here, but elsewhere under subclass 103.

105	With diaphragm-type biasing spring
	This subclass is indented under subclass 103.  Subject matter including a biasing spring usually disc shaped coaxially disposed at an end of the pile between the pile and the electromagnetic operator for exerting a compressive or releasing force on the pile in opposition to the force applied by the electromagnetic operator. (1) Note. The subject matter here usually includes a relay whose armature acts to compress or release the pile, the diaphragm spring being coaxially disposed between the armature and the pile with its center acting on the pile and supported entirely around the periphery or at, at least three peripheral points.

106	With initial pressure adjustment
	This subclass is indented under subclass 103.  Subject matter including structure such as a screw for applying a compressive force on the pile in addition to that applied by the electromagnetic operator, or on the spring, if any, which exerts a pressure releasing force on the pile in opposition to that exerted by the electromagnetic operator, the structure being adjustable as to compensate for surface wear in the piles during use. SEE OR SEARCH THIS CLASS, SUBCLASS: 109, for compressible pile type resistors generally with an initial pressure adjustment.

107	With electromagnetic holder
	This subclass is indented under subclass 101.  Subject matter including a retaining or positioning magnet for locking or holding the pressure controlling means in a predetermined position. SEE OR SEARCH THIS CLASS, SUBCLASS: 12+, for resistors wherein a movable magnet actuates the resistor through a housing or partition. 103+, for compressible pile type resistors whose pressure controlling means are actuated by an electromagnet. 189, for tap type variable resistors including a magnetic holder for the controller arm.

108	Pedal- or treadle-operated
	This subclass is indented under subclass 101.  Subject matter including structure mechanically linked with the means for varying the engagement pressure of the contact surfaces, and peculiarly adapted for operation by the foot or knee, as by being operable by a push, and including structure such as a spring for returning to the initial position upon removal of the pushing force, and including a portion shaped to facilitate engagement with the foot as by being shaped like the sole of the foot or having a substantially flat foot engaging surface. SEE OR SEARCH THIS CLASS, SUBCLASS: 153, for resistors having a contact movable along an elongated resistor, and operated by a pedal or treadle. 215, for a fixed resistor and switch combination which may be operated by a pedal or treadle. SEE OR SEARCH CLASS: 74,  Machine Element or Mechanism,   subclasses 512+ for foot operated linkage systems; subclass 515 for knee operated linkage systems; and subclasses 560+ for pedal type levers.

109	With initial pressure adjustment
	This subclass is indented under subclass 101.  Subject matter including structure such as a screw for applying a compressive force to the pile in addition to that applied by the structure normally varying the resistance value of the pile as by compression, the first mentioned structure being adjustable as to compensate for surface wear in the piles during use. SEE OR SEARCH THIS CLASS, SUBCLASS: 106, for pile type resistors with an electromagnetic operator and including an initial pressure adjustment.

110	With switch actuated by resistor actuator
	This subclass is indented under subclass 101.  Subject matter including a switch, which is operatively linked with the means for varying the engagement pressure of the engaging surfaces. SEE OR SEARCH THIS CLASS, SUBCLASS: 198, for variable resistors generally and a switch actuated by the resistor actuator. 200+, for variable resistors combined with switches generally.

111	With intervening conducting structure
	This subclass is indented under subclass 101.  Subject matter wherein a layer or coating of conducting material is provided between two adjacent wafers of the pile. SEE OR SEARCH THIS CLASS, SUBCLASS: 205, for a resistor whose element is piled or stacked in layers between terminals with an intervening conducting layer.

112	Contact surface area of piles variable
	This subclass is indented under subclass 101.  Subject matter wherein normally only a portion of the facing surfaces of the pile discs are in actual physical contact, the discs being flexible or resilient, the means for varying the engagement pressure and when actuated increasing and/or decreasing the portion of the facing surfaces in actual physical contact. SEE OR SEARCH THIS CLASS, SUBCLASS: 96, for a mechanically variable resistor having a contact strip progressively pressed along the resistance element. 114+, for mechanically variable resistors whose elements are deformable.

113	With resilient pressure-applying linkage
	This subclass is indented under subclass 101.  Subject matter wherein the means for varying the contact pressure includes a resilient spring in the linkage which transmits the pressure to the pile or on the end of the pile opposite to that where the compressive force is applied, the spring serving to progressively apply the contact pressure to the pile. SEE OR SEARCH THIS CLASS, SUBCLASS: 108, for pile type compressible resistors which are operated by a pedal or treadle, and which include a resilient spring in the pressure applying linkage.

114	Deformable
	This subclass is indented under subclass 68.  Subject matter including a flexible or deformable unitary mass of resistance material together with structure for modifying the shape of the mass, as by increasing the length or reducing the cross sectional area of the mass between terminals, to change the resistance value between the terminals. (1) Note. The mass may be granular. However, where the resistance value is changed by changing the surface pressure between the grains classification is in subclass 100 above. In this subclass (114) the shape of the resistance element itself is changed to modify the resistance value between the terminals. SEE OR SEARCH THIS CLASS, SUBCLASS: 2+, for strain gauge type resistors. 99+, for variable resistors whose surfaces are presses together, variation in the pressure changing the resistance value between terminals.

115	Element in piled or stacked layers
	This subclass is indented under subclass 68.  Subject matter wherein the element is formed of a plurality of layers of resistance material which layers are piled or stacked transversely to the direction of current flow through the resistance element, i.e., so that the current flowing through the resistance element will flow from pile to pile. (1) Note. Usually the resistance element is formed of a plurality of plates or disks of resistance material which are connected together directly or through other plates or disks of conductive material. The plates or disks are piled transversely along the length of the element, as between the resistance terminals or transversely to the path of movement of a contact moving along the resistance element. SEE OR SEARCH THIS CLASS, SUBCLASS: 7+, for a pile type resistor whose resistance value is temperature compensated. 52, for a pile type resistor with heat dissipating projections. 101+, for pile type compressible resistors. 204+, for fixed resistors whose elements are formed in layers piled or stacked between terminals. SEE OR SEARCH CLASS: 361,  Electricity: Electrical Systems and Devices,   subclasses 117+ for high voltage dissipators, per se, wherein the discharge path may be resistive disks or buttons. 428,  Stock Material or Miscellaneous Articles,   appropriate subclasses, for a plural layer stock material product, note subclass 411 for a plural layer material, one layer being of resistive material and one or more layers being conductive, so as to constitute one or more terminals; see especially subclasses 457+. 442,  Fabric (Woven, Knitted, or Nonwoven Textile or Cloth, etc.),   subclass 117 for a coated or impregnated fabric which is electrical insulating or conductivity reducing.

116	With electromagnetic operator (e.g., electric motor)
	This subclass is indented under subclass 68.  Subject matter including an electromechanical transducer such as a electric motor or a magnetic relay, the moving part such as the armature of the transducer being mechanically linked with a mechanically moving operating part of the resistor. SEE OR SEARCH THIS CLASS, SUBCLASS: 12+, for a resistor actuated by a movable magnet through a housing or partition. 32, for a resistor whose resistance value is responsive to a magnetic field. 36+, for resistors which are fluid or gas pressure actuated, and including variable resistors operated by fluid motors. 98, for a mechanically variable resistor with a motion dampening means such as a dashpot. 103+, for a pile type compressible resistor with an electromagnetic operator; and subclass 107 for such resistors with an electromagnetic holder. 189, for a mechanically variable resistor of the tap type including a magnetic holder. SEE OR SEARCH CLASS: 310,  Electrical Generator or Motor Structure,   appropriate subclasses, for electric motor structure. 318,  Electricity: Motive Power Systems,   appropriate subclasses, for motor control systems including variable resistors. 334,  Tuners,   subclasses 17+ for tuner units with an electromagnetic operator. 335,  Electricity: Magnetically Operated Switches, Magnets, and Electromagnets,   subclasses 209+ for magnets and electromagnets.