As is well known, diodes have the characteristic of unidirectional conduction and can be applied in these fields:

1. Rectification

Rectifiers are mainly used in rectifier circuits, which convert alternating current into direct current. Pulsating rectifier diodes are surface junction type, so their junction capacitance is large, resulting in a lower operating frequency, generally less than 3Hz

2. Switch

Under the action of DC voltage, the resistance of the diode is small and it is in a conducting state, which is equivalent to turning on a switch; Under the action of reverse voltage, the resistance is large and in an open state, like a disconnected switch. By utilizing the switching characteristics of diodes, various logic circuits can be formed

3. Limiting amplitude

After the diode conducts in the forward direction, its forward voltage drop remains basically unchanged (0.7V for silicon tubes and 0.3V for germanium tubes). By utilizing this characteristic as a limiting element in the circuit, the signal amplitude can be restricted within a certain range

4. Continued flow

It plays a freewheeling role in the inductance of inductive loads such as switching power supplies and relays

5. Detection

The main function of a detection diode is to detect low-frequency signals in high-frequency signals. Their structure is point contact type. Its junction capacitance is small and its operating frequency is high, so it is generally made of germanium