'Special' kind of potentiometer? SOLVED

Hey, it may be a dumb question, but i don't know, anyway here we go. So, you know those knobs that you can turn forever and do something in a circuit? Like the car stereo volume knob. It doesnt stop, yet still increases or decreases the volume. What is that named? Again, it may be a dumb question, but i've tried to find the name for that for like an hour... :/

by eldoi
February 16, 2020

1 Answer

Answer by mrobbins

For mechanical potentiometers, look up "continuous rotation potentiometer" or "endless rotation potentiometer". Note that these will rotate continuously, but there will be a step discontinuity in the resistance when they pass through a full rotation!

Your car stereo volume knob probably uses a digital rotary encoder. It's probably magnetic or optical, sensing each discrete step clockwise or counterclockwise, and digitally adjusting the volume value from that. Probably using quadrature encoding to detect which direction you're rotating it in. Wikipedia has some decent pages on this: Rotary Encoder and Incremental Encoder. Hope that helps.

ACCEPTED +1 vote
by mrobbins
February 16, 2020

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