The voltage across the rheostat is fixed if one places a variable resistance. ... As the rheostat resistance increases, the current through the bulb decreases. With equal validity, we can say that the rheostat controls the voltage in the bulb.

Does rheostat affect voltage?

We can change either the resistance on the circuit or the voltage being applied to it. ... Instead, a rheostat adjusts current (and thus in effect voltage) by increasing or decreasing resistance.

What does a rheostat control?

The rheostat can adjust generator characteristics, dim lights, and start or control the speed of motors. Its resistance element can be a metal wire or ribbon, carbon, or a conducting liquid, depending on the application.