*varistor, which is short for varying resistor, a component for which its resistance changes with the applied voltage, meaning it doesnt have a set ohm rating. A potentiometer isnt a varistor, and a varistor wouldnt be a very good dimmer, considering its ability to affect current is dependent on the voltage being applied to it, meaning to use it to dim anything, youd need to be able to dynamically reduce the applied voltage, meaning youd need a dimmer for a varistor to work as a dimmer. Also, the dimmers im talking about are made for AC current, they switch said AC current on/off at an adjustable time after the start of each half cycle, thus modulating the width of the pulses of current sent through the circuit, like i said, a version of pulse width modulation. You ever seen a dimmer switch in a house? Most likely a solid state dimmer.