A diode is a semiconductor device that allows current to flow in only one direction. It consists of two layers of semiconductor material, one with an excess of electrons (N-type) and the other with a deficiency of electrons (P-type). When a voltage is applied across the diode in the forward direction, the excess electrons from the N-type material move towards the deficiency of electrons in the P-type material, allowing current to flow. However, in the reverse direction, the diode blocks current flow due to the depletion region that forms at the junction of the two materials. This property makes diodes useful for rectifying AC voltage into DC voltage and for various other applications in electronics.
