Diodes Used in Electronic Circuits

(1) Switch circuit

In digital and integrated circuits, the unidirectional conductivity of diodes is used to realize the conduction or disconnection of circuits, and this technology has been widely used. The switching diode can protect the circuit well, prevent the circuit from being burned out due to short circuit and other problems, and can also realize the function of the traditional switch. Another characteristic of switching diodes is that the switching speed is very fast. This is unmatched by traditional switches.

(2) Limiter circuit

In electronic circuits, limiter circuits are commonly used to process various signals. It is used to selectively transmit a part of the signal within a preset level range. Most diodes can be used as limiters, but there are times when special limiter diodes are needed, such as when protecting meters.

(3) Voltage regulator circuit

Zener diodes are usually used in voltage regulator circuits, which are surface junction silicon semiconductor diodes manufactured by special processes. This special diode has a relatively high impurity concentration and a large charge density in the space charge region, which is easy to form strong electric field. When the reverse voltage across the Zener diode reaches a certain value, the reverse current increases sharply, resulting in reverse breakdown.

(4) Variable capacitance circuit

In varactor circuits, varactor diodes are often used to realize automatic frequency control, tuning, frequency modulation and sweep oscillation of the circuit.