Home > Potentiometers > Potentiometer Terminology 

1. Ground Terminal
This terminal is electrically connected to the shaft. By connecting it to the set ground, ground noise (externally-induced noise) can be prevented.

2. Numbering of Terminals
When describing the terminal numbers of a potentiometer, the terminals connected to both ends of a resistor element are called terminal 1 and terminal 3. The terminal connected to the sliding contact is called terminal 2.

3. Temperature Characteristic
Resistance variation dependant upon temperature.

4. Rotational Torque
Torque to turn the operating shaft (operating knob).

5 . Allowable Operating Torque
Maximum operating torque that the operating shaft (operating knob) can endure in its full CW or CCW position.

6. Detent 
Mechanism that provides the click feel during operation.

7. Derating Curve
Curve that shows the relationship between the ambient temperature and maximum power. (Unit: percentage to rated power).

8. Nominal Total Resistance
Resistance value that represents the specified values (reference resistance).

9. Cermet
Resistor element with excellent environment endurance formed by high-temperature baking of oxidized metal on substrate.

10 . Maximum Allowable Operating Voltage
Maximum voltage applicable to the resistor specified for the potentiometer type.
Vmax = v P. R
Vmax --- Maximum Voltage
P --- Rated power
R --- Rated resistance, Vmax equal to the limiting element voltage, when R is more than the critical resistance

11 . Maximum Resolution
Number of bits in case of an absolute-type encoder or number of pulses per revolution in case of an incremental-type encoder.

12 . Residual Resistance
Resistance (value) between the end terminal (terminal 1 or terminal 3) and the sliding terminal (terminal 2) when the control shaft (control part) is in its full CW or CCW position.

13. Allowable Force in Push-Pull Action for Lever
Maximum force at which the control part can endure without being broken when axial load is applied to the shaft (lever).

14. Shaft (lever) Play
Play of the shaft (lever) when a specified force is applied perpendicular to the shaft (lever).

15. Shaft Tilt
Parallel of perpendicular shift from the axial line or mounting surface with no load applied to the shaft, assuming the potentiometer mounting surface as reference.

16. Sliding Noise
Electrical noise that is generated when a potentiometer is operated, expressed as voltage or resistance ratio.

17. Insulation Resistance
Insulation resistance between the conductive part (terminal) of the potentiometer, and the body or shaft (lever). The larger the value, the higher the insulation.

18. Total Rotational Angle
Rotational angle of the operating shaft between both ends.

19. Total Resistance and Tolerance
A basic performance item of a potentiometer. Resistance between terminal 1 and terminal 3 and its tolerance.

20 . Gang Error
Gap between respective resistance tapers of several potentiometers that make up a multi-ganged-type potentiometer. (Unit: decibel)

21. Withstanding Voltage
Voltage at which the insulation between the conductive part of a potentiometer and the body or shaft (lever) is destroyed.

22. Tap
Terminal 4 is generally called the tap. It is installed in the middle of
the resistor and is used in loudness circuits, balance adjusting circuits, etc.

23. Carbon Film (Resistor)
Resistance element that is formed from a carbon-base film and used for general-purpose potentiometers.

24. Mounting Dimensions
Dimensions for mounting a potentiometer on a PC board.

25. Mounting Height
Height from the surface of the PC board to the top of the shaft when a rotary potentiometer is soldered on the board.

26. Solder Heat Resistance
Variation of electrical characteristics by heat during soldering.

27. Push-push
A switch that toggles on and off by repetitive push operations.

28. Friction
In a dual-shaft, multi-unit product, the inner and outer shafts interlock by frictional force. Both the inner and outer shafts that normally interlock can be shifted mutually for volume control, level control and other purposes.

29. Printed Circuit Terminal
This is a terminal to be inserted in the mounting hole of a PCB and soldered.

30. Resistance Taper
Characteristic that indicate the change in the resistance or output voltage of a potentiometer in reference with travel.

31. End Slip
This means free turning at the end of a potentiometer that has no stop mechanism (for end operation) in the control part.

Shokai Far East Ltd. 9 Elena Court  Cortlandt Manor NY 10567 914-736-3500 Fax: 914-736-3656 
E-mail: sales@shokaifareast.com   http://www.shokaifareast.com