What would a potentiometer be used for in a practical application?

A potentiometer is primarily used to control voltage in a circuit. This device works by varying the resistance in a circuit, which in turn affects the voltage drop across different components of that circuit. By adjusting the potentiometer's knob or slider, one can change the resistance, thus controlling how much voltage is applied to other parts of the circuit.

In practical applications, potentiometers are commonly used in volume controls, dimmer switches for lights, and various other devices where variable voltage is needed. The ability to adjust voltage smoothly makes them valuable in tuning and controlling electronic systems.

In contrast, while potentiometers can influence current indirectly by adjusting voltage, they do not directly increase the speed of current (which is determined by the power supply and circuit design), measure capacitance (which requires a different type of meter), or restrict current flow in the same manner as devices specifically designed for that purpose, such as resistors or fuses.