Understand the characteristics of five commonly used diodes

Understand the characteristics of five commonly used diodes

A diode is an electronic device made of semiconductor materials (silicon, selenium, germanium, etc.). Especially in various electronic circuits, reasonable connections between diodes, resistors, capacitors, inductors, and other components can be used to form circuits with different functions, which can achieve various functions such as AC rectification, detection of modulated signals, limiting and clamping, and voltage stabilization of power supply. It can be seen in both household appliances and industrial control circuits.

Here are the characteristics of five commonly used diodes:

1. Rectifier diode:

Rectifier diodes can convert AC power into DC current, but due to the large junction capacitance, the operating frequency is low. In general, diodes above IF1 ampere are usually packaged in metal shells, which is beneficial for heat dissipation. diodes below IF1 ampere are mostly packaged in all plastic packaging.

2. Switching diode:

As the name implies, switching diodes are mainly used in pulse digital circuits to make and break circuits. Their reverse recovery time is relatively short, which can meet the needs of high frequency and Super high frequency. Switching diodes can be divided into contact type, planar type and diffusion mesa type. Silicon switching diodes with IF less than 500 mA are mostly sealed with epoxy resin or ceramic chip packaging.

3. Zener diode:

Zener diode, also known as Zener diode, plays a stabilizing role in the circuit by utilizing the reverse breakdown state of the PN junction;

4. Varactor diode:

Varactor diode is a nonlinear capacitive component made of the characteristic that the capacitance of PN junction changes with the applied bias voltage. It is widely used in parametric amplifiers, Frequency multiplier, electronic tuning and other microwave circuits. The non-linear relationship between capacitance and voltage is mainly highlighted through structural design and process, and the Q value is increased to be suitable for application.

5. TVS diode:

TVS diode, also known as transient voltage suppressor, is connected in parallel with the protected circuit. When the transient voltage exceeds the normal working voltage of the circuit, the diode avalanches, providing a path for the transient current, preventing the internal circuit from being damaged by excessive voltage or excessive current overheating. Due to the large junction area of TVS diode, it has the advantage of discharging large transient current and has an ideal protective effect.