Two ways of using a potentiometer

140

01:27:40

The left variant shows the usage of a potentiometer as a voltage divider while the right variant uses it as a variable resistor, leaving the voltage unaffected. 

In use with Arduino's Analog pins, always use the left variant as the Arduino detects voltage steps and thus needs a voltage divider.

Have fun!

published 9 years ago

hurz

9 years ago

The golden rule is, never leave a potentiometer pin open! http://everycircuit.com/circuit/5442513615716352

thebugger

9 years ago

Yeah I gotta agree with Hurz. The idea is that in a negative feedback there's a possibility that the wiper may fall in a place where the resistance is very high (where it doesn't make good contact with the resistive plate for instance). This way the gain increases to a maximum and may lead to instabilities or even oscillations. By connecting the third terminal you virtually limit the maximum gain even in a worst case scenario. I've had such problems and while in theory it doesn't really matter in practice it's always good to do so.

thebugger

9 years ago

P.S. Sometimes when the potentiometer is at the other end of the negative feedback, there's no need to connect the third terminal because if the wiper should fail to make contact, the gain falls to a minimum and the stability is at maximum. But as hurz said it's always good to keep it connected

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