What is the difference between a potentiometer and a rheostat?

A potentiometer varies voltage by using a three-terminal device that adjusts the voltage output based on the position of a wiper moving across a resistive element. This allows it to divide voltage and is commonly used in applications such as volume controls in audio equipment.

In contrast, a rheostat is essentially a variable resistor that is primarily used to control current in a circuit. It typically has two terminals and can adjust the resistance, thereby changing the current flowing through the circuit without changing the voltage. This functionality makes it useful in applications where specific current levels are critical, such as in dimmer switches or motor speed controls.

The distinction between voltage and current control is fundamental to understanding the operational differences between these two components. A potentiometer's ability to control voltage while a rheostat focuses on controlling current directly relates to their specific applications and circuit behavior.