Final answer:
The symbol for a potentiometer in a schematic diagram is usually represented by the letter R. It is a type of resistor used to adjust potential or voltage in an electrical circuit.
Step-by-step explanation:
The symbol for a potentiometer in a schematic diagram is usually represented by the letter R. This is because a potentiometer is a type of resistor that enables the adjustment of potential or voltage in an electrical circuit. It is commonly used for voltage division or to measure and control electrical currents.