How to test Zener diode with multimeter
The regulator value of the voltage regulator tube we usually use is generally greater than 1.5V, and the resistance file below R×1k of the pointer meter is powered by the 1.5V battery in the meter. In this way, use the resistance file below R×1k Measuring a Zener tube is like measuring a diode, which has complete unidirectional conductivity. However, the R×10k gear of the pointer meter is powered by a 9V or 15V battery. When the R×10k is used to measure a voltage regulator tube with a voltage regulation value less than 9V or 15V, the reverse resistance value will not be ∞, but will have a certain value. Resistance value, but this resistance value is still much higher than the forward resistance value of the Zener tube. In this way, we can initially estimate the quality of the Zener tube. However, a good Zener tube must have an accurate voltage regulation value. How to estimate this voltage regulation value under amateur conditions? It is not difficult, just find a pointer meter. The method is: first place a meter in the R×10k range, and its black and red test leads are respectively connected to the cathode and anode of the voltage regulator tube. At this time, the actual working state of the voltage regulator tube is simulated, and then another meter is placed in the On the voltage file V×10V or V×50V (according to the regulated voltage value), connect the red and black test leads to the black and red test leads of the watch just now, and the measured voltage value at this time is basically this Regulated voltage value of the Zener tube. Saying "basically" is because the bias current of the first meter to the regulator tube is slightly smaller than the bias current in normal use, so the measured voltage regulator value will be slightly larger, but basically the same . This method can only estimate the Zener tube whose voltage regulator value is less than the voltage of the high-voltage battery of the pointer meter. If the regulated voltage value of the Zener tube is too high, it can only be measured with an external power supply (in this way, when we choose a pointer meter, it is more suitable to choose a high-voltage battery with a voltage of 15V than 9V).
