What is the normal working state of a voltage regulator diode? How to measure good or bad?

What is the normal working state of a voltage regulator diode? How to measure good or bad?

When the voltage regulator is working normally, it is in a reverse breakdown state, and this interval is recoverable. Don't mistakenly think that seeing the word 'breakdown' means the device is damaged. Zener diodes are also a type of diode, and diodes are equivalent to PN junctions, which are made using the characteristics of PN junctions.

Zener diode, also known as voltage regulator diode. A diode that functions as a voltage regulator by utilizing the reverse breakdown state of a PN junction, where the current can vary widely while the voltage remains relatively constant. 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 very small value. In this low resistance region, the current increases while the voltage remains constant. Zener diodes are divided according to the breakdown voltage, and because of this characteristic, they are mainly used as voltage regulators or voltage reference components.

Methods for measuring the quality of voltage regulator diodes:

1. Voltage measurement method, this measurement method is relatively simple. We usually use the DC voltage range of a digital multimeter to directly measure the output voltage regulation value of a voltage regulator diode. If the measured DC voltage result is equal to the voltage regulation value of the voltage regulator diode, it means that the voltage regulator diode is working normally and its diode is good.

2. Use a shaking table to measure high-voltage voltage regulators. Sometimes, we can also use a shaking table to detect voltage regulators with higher voltage regulators. We connect the terminals of the megohmmeter to the diode and shake the handle of the megohmmeter according to the rated speed. When we find that the megohmmeter stays relatively stable at a certain scale, it indicates that the quality of the voltage regulator diode is good. If the swing is severe, it indicates that the quality of the voltage regulator diode is poor or it is not a voltage regulator diode at all.

3. Resistance measurement method: First, set the ohm range of the multimeter to RX1K, connect the black probe (positive terminal of the multimeter battery) to the negative terminal of the voltage regulator diode, and connect the red probe (negative terminal of the multimeter battery) to the positive terminal. At this point, the reading of the multimeter should be very large, reaching hundreds of kiloohms. Then shift the ohm range of the multimeter pointer to RX10K. This indicates a significant decrease in resistance, suggesting that the voltage regulator diode is in a breakdown state and that the diode is in good condition. On the contrary, the voltage regulator has problems or is not a voltage regulator diode.