The Structure Of The Diode

The diode is encapsulated by a PN junction plus the corresponding electrode lead and tube shell.

Using different doping processes, the P-type semiconductor and the N-type semiconductor are fabricated on the same semiconductor (usually silicon or germanium) substrate through diffusion, and a space charge region is formed at their interface called a PN junction.

Figure 1 Symbols of various diodes

Figure 1 Symbols of various diodes

The electrode drawn from the P region is called the anode, and the electrode drawn from the N region is called the cathode. Because of the unidirectional conductivity of the PN junction, when the diode is turned on, the current direction is from the anode to the cathode through the inside of the tube.

The circuit symbol of the diode is shown in Figure 1. The diode has two electrodes, the electrode drawn from the P area is the positive electrode, also called the anode; the electrode drawn from the N area is the negative electrode, also called the cathode. The direction of the triangular arrow indicates the direction of the forward current, and the text symbol of the diode is represented by VD.