how to measure a potentiometer?

[thebucketmouse]

I'm following a guide to make a driver for a laser diode, and it calls for a 100 ohm potentiometer. I bought an assortment of them from Radio Shack, but they have no resistance values written anywhere on them, and the pack they came in just says "Potentiometers". How can I measure these things to find their resistance?

 

[geek]

I'm following a guide to make a driver for a laser diode, and it calls for a 100 ohm potentiometer. I bought an assortment of them from Radio Shack, but they have no resistance values written anywhere on them, and the pack they came in just says "Potentiometers". How can I measure these things to find their resistance?

I think I've bought the same pack before, there are not any 100 ohm pots in it. All of them are on the order of kilo-ohms if I remember right. You'll probably have to order one from digikey or mouser.

If you want to measure them, just connect a multimeter and start twisting the screw on the pot until the resistance peaks.

 

[Deleted member 13229]

Usually you can substitute the 25 ohm rheostat from Radioshack for the 100 ohm pot.

 

[AP_Digital_light]

I'm following a guide to make a driver for a laser diode, and it calls for a 100 ohm potentiometer. I bought an assortment of them from Radio Shack, but they have no resistance values written anywhere on them, and the pack they came in just says "Potentiometers". How can I measure these things to find their resistance?

Potentiometer has three terminals.
Side(1 and 3) terminals are connected to resistive element, so resistance between them is always constant.
Medium (2) terminal is connected to slider, so resistance between it and any side terminals changes if you turn shaft.
Set your multimeter to resistance measuring and connect to side(1 and 3) terminals and read data measured by multimeter. That's nominal resistance of potentiometer.