What is the main use of a potentiometer in electrical circuits?

The primary function of a potentiometer in electrical circuits is to adjust voltage levels. A potentiometer is essentially a variable resistor that allows for the control of the voltage supply in a particular circuit by changing its resistance. By turning the knob or sliding the lever, the resistance changes, which in turn alters the voltage drop across it according to Ohm's law.

This capability makes potentiometers very useful for tuning circuits, controlling brightness in lighting applications, and managing volume in audio devices. The versatility of a potentiometer comes from its ability to precisely set different voltage levels, making it an essential component in analog control systems.

In contrast, measuring current is typically done using an ammeter, limiting resistance involves fixed resistors, and supporting battery discharge does not accurately describe the primary function of a potentiometer.