resister, resistor

Resister or resister means someone who opposes or resists something, such as the draft ( military conscription )--
He was a draft resister in the 1960's, but now he's very conservative.
He was a war resister and a subversive when he was in college, so he can't get a security clearance.

Resistor or resistor means a device designed to introduce resistance into an electrical circuit--
A resistor reduces current flow and lowers voltage levels.
The dimmer switch in a lamp is made with a variable resistor.

Now that you know that, you can say--
"The resistor that operates the volume control is broken; we may not be able to hear the draft resister speak."