Five knowledge points that diodes must know — SUNMATE
Five 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. Theoretically, for silicon diodes, the diode of BAV99 model can pass through greater DC current with square wave measurement conditions. If the square wave is the same as the average current of DC current, it will damage the BAV99 diode. The diode of 5A passes through the current of 5A. If the temperature is too high due to insufficient heat dissipation conditions, the current of BAV99 diode will be limited by the junction temperature.
2. Reverse rated voltage
When the BAV99 diode is reversely cut off, if it can withstand a certain reverse voltage, the maximum value of the reverse pressure is a fixed voltage. For example, the rated current of 5A / 100 volt BAV99 diode is 100 volts, but some manufacturers can use 110 volts for the 100 volt BAV70 diode manufactured in order to keep Yude, but exceeding the rated value can not ensure the stability of the diode. This problem is their own problem.
3. Forward impulse current
Under power on or other transient conditions, the diode is required to withstand large impulse current without damage. Naturally, such impulse current is not repeated or the interval is long. Under normal circumstances, there is such a definition of impulse current in the diode data book. Its test condition is usually a single sine wave or square wave, and its current value can usually reach hundreds.
4. Forward conduction voltage drop
When BAV99 diode is conducting in the forward direction, the current flowing will produce a voltage drop. The pressure drop is related to positive current and temperature. General silicon diode, the greater the current, the greater the voltage drop. With the increase of temperature, the pressure loss decreases.
5. Reverse leakage current
When BAV99 diode is cut off in reverse, the cut-off is not ideal. When subjected to back pressure, some small current will leak from the cathode to the anode. The current is generally small, the reverse voltage is high, the leakage current is also large, the temperature is high, and the leakage current is large. Large leakage current and loss, especially in high voltage environment.