What type of variable resistor is typically used to provide a variable voltage?

What type of variable resistor is typically used to provide a variable voltage?

• A. Rheostat
• B. Thermistor
• C. Capacitor
• D. Potentiometer

Answer: (D)

To get a variable voltage, you use a device that can split the supply into a controllable proportion. A potentiometer does exactly that: it’s a three-terminal resistor with a movable contact (the wiper) that slides along a resistive track. Connect the ends to your supply and ground, and take the output from the wiper. By turning the knob, you change the ratio of resistance above and below the wiper, giving you a voltage that varies from 0 to the full supply. This makes it ideal as a voltage divider for adjustable outputs in circuits like audio controls or sensor inputs. The other options don’t fit as well. A thermistor changes resistance with temperature, not knob position. A capacitor stores charge but doesn’t provide a controllable output voltage. A rheostat is a two-terminal variable resistor used mainly to adjust current, not to supply a stable, adjustable voltage at a node.

To get a variable voltage, you use a device that can split the supply into a controllable proportion. A potentiometer does exactly that: it’s a three-terminal resistor with a movable contact (the wiper) that slides along a resistive track. Connect the ends to your supply and ground, and take the output from the wiper. By turning the knob, you change the ratio of resistance above and below the wiper, giving you a voltage that varies from 0 to the full supply. This makes it ideal as a voltage divider for adjustable outputs in circuits like audio controls or sensor inputs.

The other options don’t fit as well. A thermistor changes resistance with temperature, not knob position. A capacitor stores charge but doesn’t provide a controllable output voltage. A rheostat is a two-terminal variable resistor used mainly to adjust current, not to supply a stable, adjustable voltage at a node.