About Diode

A diode is an electronic component that allows current to flow in one direction only. A PN type diode, which is a junction of an N type semiconductor and a P type semiconductor, is often used. N-type semiconductors are semiconductors in which there are extra electrons compared to the positive charges of the atomic nucleus. The surplus electrons are called free electrons, and when a voltage is applied, they move from the negative side to the positive side. N-type semiconductors are semiconductors in which there are extra electrons compared to the positive charges of the atomic nucleus. The surplus electrons are called free electrons, and when a voltage is applied, they move from the negative side to the positive side. When a voltage is applied to a PN junction diode so that the P side becomes positive and the N side becomes negative, the holes that have moved to the negative side and the electrons that have moved to the positive side meet at the PN junction surface, and the electrons on the N side and the holes on the P side meet. combine and both disappear. For that amount, electrons are supplied from the power supply to the N side, electrons flow out from the P side and holes are generated, and current flows from the P side to the N side. Conversely, when a negative voltage is applied to the P side and a positive voltage is applied to the N side, the holes move to the negative side and the electrons move to the positive side. The characteristic of diodes that allow current to flow in one direction is used as switches and rectifiers.