knowledge points that diodes must know

knowledge points that diodes must know

1. Forward rated current

What is the rated current? For example, for a diode of 5 A/100V, 5 A is the rated current, and the rated current is the main nominal value of the diode. In theory, for silicon diodes, the BAV99 model diode can pass a larger DC current using square wave measurement conditions. If the square wave and the average current of the DC current are the same, it will cause damage to the BAV99 diode model. If the heat dissipation conditions of the 5A diode are insufficient and the temperature is too high, the current passing through the BAV99 diode will be limited by the junction temperature.

2. Reverse rated voltage

When the BAV99 diode is cut off in reverse, if it can withstand a certain reverse voltage, the highest value of the reverse pressure is a fixed voltage. For example, the rated current of the 5A/100 volt BAV99 model diode is 100 volts, but some manufacturers have created a 100 volt BAV70 model diode to keep Yude, which can be used up to 110 volts. However, exceeding the rated value cannot guarantee the stability of the diode. If this problem arises, it is their own problem.

3. Forward impulse current

Under power-on or other transient conditions, it is required that the diode can withstand a large impulse current without damage. Naturally, such impulse currents are not repetitive or have a long interval. Under normal circumstances, there is a definition of impulse current in the data manual of diodes, and its testing conditions are usually a single sine wave or square wave, with current values typically reaching several hundred.

4. Forward conduction voltage drop

When the BAV99 diode is conducting in the forward direction, the current flowing through it will generate a voltage drop. The pressure drop is related to positive current and temperature. Generally, a silicon diode has a higher current and a higher voltage drop. As the temperature increases, the pressure loss decreases.

5. Reverse leakage current

When the BAV99 diode is cut off in reverse, the cutoff is not ideal. When subjected to back pressure, there will be some small current leakage from the cathode to the anode. The current is generally small, and the reverse voltage is high. The leakage current is also large, and the temperature is high, resulting in a large leakage current. Large leakage current and loss, especially in high voltage environments.