potmeter

A potmeter, short for potentiometer, is a passive three-terminal electronic component used to adjust electrical signals. It consists of a resistive element, typically carbon, cermet, or wire-wound, and a movable contact called a wiper. The two outer terminals connect to the ends of the resistive element, while the middle terminal is connected to the wiper. By changing the position of the wiper, the resistance between the terminals changes, enabling signal control.

When used as a voltage divider, an input voltage is applied across the end terminals, and the wiper provides a variable fraction of that voltage to the output. When used as a variable resistor, the wiper and one end form a changing resistance. Potmeters come in rotary form, with a shaft and knob, and linear form, with a sliding element. Tapers describe how resistance changes with movement; common tapers are linear and logarithmic (audio). Typical values range from a few ohms to hundreds of kiloohms.

Construction and ratings vary. Potmeters can be through-hole or surface-mount, and come in compact panel types or larger chassis designs. Power ratings commonly span from about 0.125 W to 0.5 W for standard panel pots, with higher ratings available for specialized applications. Lifespan depends on design and usage, often tens of thousands of rotation or slide cycles. Factors such as contact resistance drift, dust, and mechanical wear affect performance.

Applications include volume and tone controls in audio equipment, user interface controls in consumer electronics, and trim potentiometers used for circuit calibration. In precision work, multi-turn trimming pots provide finer adjustment. The term potmeter is used in some regions as a synonym for potentiometer, and is often shortened to “pot.” Selection depends on taper, value, and rating.