Passive Components

A capacitor stores electrical energy in an electric field. The symbol shows two parallel plates separated by a gap.

An inductor stores energy in a magnetic field when current flows through it. The symbol shows a series of curved humps or loops representing the coiled wire. Inductors oppose changes in current and are used in filters, transformers, and energy storage.

A potentiometer is a three-terminal variable resistor used as a voltage divider. The symbol shows a resistor with an arrow pointing to a third terminal (the wiper). Potentiometers are commonly used for volume controls, position sensors, and calibration adjustments.

A resistor opposes the flow of electrical current. The fixed resistor symbol shows a zigzag line (US/ANSI standard) or a rectangle (IEC standard).

A variable resistor allows its resistance value to be manually adjusted. The symbol is a standard resistor zigzag with an arrow through it indicating adjustability. Variable resistors are used for dimming lights, controlling motor speed, and setting bias levels.