I am using a pot to control LCD contrast, works great. Except, I am low on parts and would like to use this exact pot elsewhere.
So, I try to measure the resistance between the first and middle pins on the pot, match that to a single resistor, hook one to power, and the other to the contrast pin. Nothin!
Am I doing something wrong here? I also tried measuring power with the pot plugged in and set the way I want, but that is not getting me where I need to be either. What is the right way to do this, or is there one?
You can not replace a potential divider with only one resistor you need two.
Measure wiper to one pin like you did then wiper to the other pin and replace each half of the pot with a resistor of the same value.
And if you keep the display at the same temperature and the same voltage, those two resistors will do fine.
Aha! I somehow thought that pots were nothing more than adjustable resistors. No wonder this does not work!
Thanks for the explanation, and sorry for the total newb status
thought that pots were nothing more than adjustable resistors
The clue is in the name. Pot - short for potential divider
Or, in some circles, short for potentiometer.
You can of course use a potentiometer as a variable resistor, proper name rheostat, by using one fixed terminal and the wiper terminal as the two system lines It's also good practice to connect the remaining fixed terminal to the wiper so that, in the event of the wiper lifting from the track, the system will "see" the the potentiometer full resistance value rather than an open circuit.