A diode is a passive electronic component that allows current to flow in only one direction. There are several types of diodes, as listed in the circuit symbol diagram. The arrow in the diagram points in the direction of "easy" current flow.
Circuit symbol
Applications
Diodes are often used for rectifying an ac voltage to a dc voltage.
Photodiodes are a special type of diode that allows current to flow only when light strikes the photodiode. These components are useful as light detectors.
