A diode consists of a die case and two electrodes
A diode consists of a die, a case and two electrodes. The die is a PN junction, and a lead is drawn out at both ends of the PN junction, and plastic, glass or metal materials are used as the package shell to form a crystal diode, as shown in the figure below. The lead-out electrode of the P region is called the positive pole or anode, and the lead-out electrode of the N region is called the negative pole or cathode.