When the voltage stabilizing tube works normally, it is in the reverse breakdown state, and the interval is recoverable. Don’t mistake the word “breakdown” for a damaged device. Zener is also a kind of diode. The diode is equivalent to a PN junction, which is made by using the characteristics of the PN junction.
Zener diode is also called zener diode. Using the reverse breakdown state of PN junction, its current can change in a large range while the voltage is basically unchanged, which is a diode used for voltage stabilization. This diode is a semiconductor device with high resistance until the critical reverse breakdown voltage. At this critical breakdown point, the reverse resistance decreases to a small value. In this low resistance area, the current increases while the voltage remains constant. The voltage stabilizer diode is graded according to the breakdown voltage. Because of this feature, the voltage stabilizer is mainly used as a voltage regulator or voltage reference element.
Methods for measuring the quality of zener diode:
- The voltage measurement method is relatively simple. We usually use the DC voltage range of the digital multimeter to directly measure the output voltage stabilizing value of the voltage stabilizing diode. If the measured DC voltage result is equal to the voltage stabilizing value of the voltage stabilizing diode, it indicates that the voltage stabilizing diode is working normally and that the diode is good.
- Use a megger to measure the high voltage regulator diode. Sometimes we can use a megger to detect the regulator diode with high voltage. We connect the terminal of the megger to the diode, and shake the handle of the megger according to the rated speed. When the megger is found to stay stably at a certain scale, it indicates that the quality of the megger is a good zener diode. If the swing is severe, it indicates that the quality of the zener diode is poor or it is not a zener diode at all.
- For resistance measurement, first use the ohm gear of the pointer multimeter to switch to the RX1K gear, connect the black probe (the positive pole of the pointer multimeter battery) to the negative pole of the voltage regulator diode, and connect the red probe (the negative pole of the pointer multimeter battery) to the positive pole. At this time, the indicated value of the multimeter should be very large, which can reach hundreds of kiloohms. Then turn the ohm gear of the pointer multimeter to the RX10K gear. This shows that there should be a significant drop in the resistance, indicating that the zener diode is in a breakdown state and that the diode is good. On the contrary, there is a problem with the regulator or it is not a regulator diode.
I believe that through reading the above content, we have a preliminary understanding of zener diodes. At the same time, we hope you can make a good summary in the learning process, so as to constantly improve your professional level.