How to avoid diode overload damage
As a basic electronic component, the diode is known to all engineers for its unidirectional conductivity. According to the classification of semiconductor materials, it can be divided into silicon diodes and germanium diodes; according to the classification of applications, it can be divided into rectifier diodes, detector diodes, switching diodes and Zener diodes. No matter how it is divided, it is believed that the diode has a very important parameter, which will directly affect whether the transistor will be damaged due to overload.

Dissipated power
Dissipated power is also called the maximum allowable collector dissipation power PCM, which refers to the maximum collector dissipation power when the change in transistor parameters does not exceed the specified allowable value. It is the difference between the total active input power and the total active output power of grid components or the entire network at a certain time. Under linear conditions, the calculation of the conduction power dissipation is relatively simple, PD=I2R, or PD=U2/R; while in the switching state, the calculation is relatively complicated.

The power dissipation of the diode is related to the allowable junction temperature. The maximum allowable junction temperature for silicon diodes is 150°C, while the maximum allowable junction temperature for germanium is 85°C. The operating temperature of a semiconductor is limited. When the actual power increases, the junction temperature will also increase. When the junction temperature reaches 150°C, the power at this time is the maximum power dissipation. Of course, the power dissipation also has a certain relationship with the package size. Usually, the maximum power dissipation is relatively large when the device is packaged with a larger size. The most common is that the high-power device has a large volume and a large area of heat dissipation metal surface.


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