What type of variable resistor is designed to control voltage?

What type of variable resistor is designed to control voltage?

• A. Preset variable resistor
• B. Potentiometer
• C. Rheostat
• D. Relay switch

Answer: (B)

The potentiometer is designed specifically to control voltage within a circuit. It functions by varying its resistance, which in turn changes the voltage drop across it. A potentiometer typically consists of three terminals: two connected to a voltage source and the third connected to a load. By adjusting the position of a sliding contact (the wiper), one can effectively tap into the voltage at a desired level, making it suitable for applications such as volume control in audio equipment or as a tuning control. In contrast, a preset variable resistor is usually adjusted only once during installation and isn’t generally intended for continuous adjustment. The rheostat, while also a variable resistor, is primarily used to control current, typically in higher power applications. Lastly, a relay switch functions as an electrically operated switch but does not inherently control voltage. Thus, the characteristics and intended function of the potentiometer align it closely with the objective of controlling voltage in electrical circuits.

The potentiometer is designed specifically to control voltage within a circuit. It functions by varying its resistance, which in turn changes the voltage drop across it. A potentiometer typically consists of three terminals: two connected to a voltage source and the third connected to a load. By adjusting the position of a sliding contact (the wiper), one can effectively tap into the voltage at a desired level, making it suitable for applications such as volume control in audio equipment or as a tuning control.

In contrast, a preset variable resistor is usually adjusted only once during installation and isn’t generally intended for continuous adjustment. The rheostat, while also a variable resistor, is primarily used to control current, typically in higher power applications. Lastly, a relay switch functions as an electrically operated switch but does not inherently control voltage. Thus, the characteristics and intended function of the potentiometer align it closely with the objective of controlling voltage in electrical circuits.