Variable Capacitor - Trimmer

Thread Starter


Joined Nov 19, 2007
Hi All

This is probally a very straight foward question for you guys, i have bought a varaible capacitor for a circuit i am building but am a little confused as to how to wire it up. there are 3 pins on it to of which that look the same and one with a red marking on it. Do i connect the 2 that are the same to plus and minus of my battery and then take my trimmed amount off the red terminal or what way?

Many thanks


Joined Apr 20, 2004
The capacitor should have a data sheet that explains which pin is which. Your guess about the pins is probably good. With a meter set to ohms, the two pins that read as a short are one side of the cap, and the third, which will check open, will be the variable side.

I am also confused - why a variable capacitor attached to a battery? They are usually used as oscillator trims. Attaching the two pins with continuity to the plus and minus of the battery just shorts it out. Perhaps you have confused variable capacitors with potentiometers which are resistive devices.