What is a diode?
A diode is an electronic device made of semiconductor materials (silicon, selenium, germanium, etc.), consisting of a PN junction plus corresponding electrode leads and a tube shell package. A diode has two electrodes, the positive electrode, also called the anode; the negative electrode, also called the cathode. When a forward voltage is applied between the two electrodes of the diode, the diode is turned on, and when a reverse voltage is applied, the diode is cut off. The conduction and cutoff of the diode are equivalent to the on and off of the switch.
A diode has unidirectional conductivity. When it is turned on, the current flows from the anode through the tube to the cathode.
Common classifications of diodes are: point contact diodes, surface contact diodes, planar diodes, voltage regulator diodes, photodiodes and light-emitting diodes.
Common diodes are: 1N4148 SMD or DIP, 1N4001, 1N5824, S4 Diode.
