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Potentiometer

This article is about the electrical component. For the measuring instrument, see Potentiometer

(measuring instrument).

Potentiometer

A typical single-turn potentiometer

Type

Passive

Electronic symbol

(International)

(US)

A potentiometer /pɵˌtɛnʃiˈɒmɨtər/, informally a pot, is a three-terminal resistor with a sliding or

rotating contact that forms an adjustable voltage divider.

[1]

If only two terminals are used, one end

and the wiper, it acts as a variable resistor or rheostat.

The measuring instrument called a potentiometer is essentially a voltage divider used for

measuring electric potential (voltage); the component is an implementation of the same principle,

hence its name.

Potentiometers are commonly used to control electrical devices such as volume controls on audio

equipment. Potentiometers operated by a mechanism can be used as position transducers, for

example, in a joystick. Potentiometers are rarely used to directly control significant power (more than

a watt), since the power dissipated in the potentiometer would be comparable to the power in the

controlled load.

Summary of content (9 pages)

PAGE 1
Potentiometer This article is about the electrical component. For the measuring instrument, see Potentiometer (measuring instrument). Potentiometer A typical single-turn potentiometer Type Passive Electronic symbol (International) (US) A potentiometer /pɵˌtɛnʃiˈɒmɨtər/, informally a pot, is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider.[1] If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat.
PAGE 2
Nomenclature There are a number of terms in the electronics industry used to describe certain types of potentiometers:    slide pot or slider pot: a potentiometer that is adjusted by sliding the wiper left or right (or up and down, depending on the installation), usually with a finger or thumb thumb pot or thumbwheel pot: a small rotating potentiometer meant to be adjusted infrequently by means of a small thumbwheel trimpot or trimmer pot: a trimmer potentiometer typically meant to be adjusted once or i
PAGE 3
PCB mount trimmer potentiometers, or "trimpots", intended for infrequent adjustment Electronic symbol for pre-set potentiometer Others are enclosed within the equipment and are intended to be adjusted to calibrate equipment during manufacture or repair, and not otherwise touched. They are usually physically much smaller than user-accessible potentiometers, and may need to be operated by a screwdriver rather than having a knob. They are usually called "preset potentiometers" or "trim[ming] pots".
PAGE 4
Size scaled 10k and 100k pots that combine traditional mountings and knob shafts with newer and smaller electrical assemblies. Note the "B" designating a linear taper. The relationship between slider position and resistance, known as the "taper" or "law", is controlled by the manufacturer. In principle any relationship is possible, but for most purposes linear or logarithmic (aka "audio taper") potentiometers are sufficient.
PAGE 5
Rheostat See also: Liquid rheostat Charles Wheatstone's 1843 rheostat with a metal and a wooden cylinder Charles Wheatstone's 1843 rheostat with a moving whisker The most common way to vary the resistance in a circuit is to use a rheostat.
PAGE 6
 Electronic Symbol for pre-set rheostat  A high power wirewound potentiometer. Digital potentiometer Main article: Digital potentiometer A digital potentiometer (often called digipot) is an electronic component that mimics the functions of analog potentiometers. Through digital input signals, the resistance between two terminals can be adjusted, just as in an analog potentiometer.
PAGE 7
it has a transparent resistive coating. A finger or stylus deforms the glass to contact the underlying layer. Edges of the resistive layer have conductive contacts. Locating the contact point is done by applying a voltage to opposite edges, leaving the other two edges temporarily unconnected. The voltage of the top layer provides one coordinate. Disconnecting those two edges, and applying voltage to the other two, formerly unconnected, provides the other coordinate.
PAGE 8
Television Potentiometers were formerly used to control picture brightness, contrast, and color response. A potentiometer was often used to adjust "vertical hold", which affected the synchronization between the receiver's internal sweep circuit (sometimes a multivibrator) and the received picture signal, along with other things such as audio-video carrier offset, tuning frequency (for push-button sets) and so on.
PAGE 9
(dividing throughout by RL and cancelling terms with RL as denominator) As an example, assume , , , and Since the load resistance is large compared to the other resistances, the output voltage VL will be approximately: Due to the load resistance, however, it will actually be slightly lower: ≈ 6.623 V.