How to find the right Variable Resistors AI guide

Written by an AI model from its trained knowledge.

What the AI looks for in Variable Resistors

Role in the circuit: Use a potentiometer (three terminals, voltage divider) for signal-level control, and a rheostat (two terminals, wirewound) when you must carry and limit load current. Panel potentiometers handle only fractions of a watt, so using one to control load current burns out the track.
Power rating: Size for the dissipation at the worst-case setting with margin; carbon and cermet panel pots are typically well under a watt, and wirewound rheostats are rated in tens to hundreds of watts. Overheating is the main failure mode of variable resistors.
Adjustment frequency: Use a trimmer for set-and-forget calibration, a panel pot for user controls, and a multi-turn precision pot for fine settings that must be repeatable. Trimmers are rated for very few adjustment cycles compared with panel controls.
Element material: Carbon is for low-cost audio and general controls. Cermet gives stability and heat tolerance. Conductive plastic gives long life and smooth output. Wirewound is for power and precision. The element sets noise, rotational life, temperature stability and power handling.
Physical fit: Match the body size, the mounting style (PCB, panel or solder lug), the shaft type and diameter, and the bushing thread to your board, panel and knob. Most wrong orders are mechanical mismatches, not electrical ones.

Bourns: Broad range, from trimmers to precision multi-turn and panel pots.
Ohmite: The reference name for wirewound rheostats.
Vishay: Precision and industrial pots and trimmers, including the Spectrol range.
Alps Alpine: Well regarded for audio-grade rotary and slide pots.
CTS: Common in panel and instrument controls.
TT Electronics: Industrial trimmers and precision pots, including the BI Technologies range.

Choose a rheostat when the part carries load current, and a potentiometer when it only sets a voltage or signal level.