Potentsiomeeter

Potentsiometer, also spelled potentiometer in many contexts, is a three-terminal electrical device used to measure or adjust electrical potential. In electronics the term usually refers to a passive variable resistor and voltage divider consisting of a resistive element and a movable contact, or wiper. The position of the wiper determines the output resistance or the fraction of a supply voltage delivered to the load. A rotary potentiometer uses a circular resistive track and a rotating knob; a linear potentiometer employs a sliding contact along a resistive strip. Electrical specifications include end-to-end resistance, taper (linear or logarithmic), power rating, and resistance temperature coefficient. Digital potentiometers replace mechanical contacts with electronic switches to set discrete resistance values.

Potentiometers serve as adjustable controls in audio equipment, instrumentation, and control systems, and as position sensors in robotics. As a voltage divider, they provide a controllable output voltage for user interfaces, sensor interfaces, or calibration networks. In the history of metrology, the potentiometer refers to a balance instrument, such as the slide-wire or Kelvin potentiometer, used to compare an unknown emf with a standard cell by nulling a galvanometer. This balance method requires a stable source and high sensitivity and is largely of historical interest today.

Construction: devices may use carbon film, conductive plastic, or wire-wound resistive elements; wear of the wiper can cause drift. Design choices include taper, travel length, mechanical robustness, and thermal stability. Proper calibration and, for metrological use, temperature control are important for accuracy. Modern variants, the digital potentiometer, use semiconductor switches and provide programmable resistance without moving parts, enabling integration in complex circuits and microcontroller systems.