Introduction to measuring zener diodes with multimeter
The voltage stabilization value of the voltage regulator tubes we usually use is generally greater than 1.5V, and the resistance range below R×1k of the pointer meter is powered by the 1.5V battery in the meter. In this way, the resistance range below R×1k is used Measuring the Zener tube is just like measuring the diode, it has complete one-way conductivity. However, the R×10k range of the pointer meter is powered by a 9V or 15V battery. When using R×10k to measure a voltage regulator tube with a voltage regulator value less than 9V or 15V, the reverse resistance will not be ∞, but will have a certain value. resistance, but this resistance is still much higher than the forward resistance of the voltage regulator tube.
In this way, you can initially estimate the quality of the voltage regulator tube. However, a good voltage regulator tube must have an accurate voltage regulator value. How to estimate this voltage regulator value under amateur conditions? It's not difficult, just find an analog watch.
The method is: first put a meter in the R×10k position, and connect its black and red test leads to the cathode and anode of the voltage regulator tube respectively. At this time, the actual working state of the voltage regulator tube is simulated, and then take another meter and put it in the R×10k position. At the voltage level V×10V or V×50V (according to the voltage regulator value), connect the red and black test leads to the black and red test leads of the watch just now. The voltage value measured at this time is basically this The voltage stabilization value of the voltage regulator tube.
I say "basically" because the bias current of the voltage regulator tube of the first meter is slightly smaller than the bias current during normal use, so the measured voltage regulator value will be slightly larger, but the difference is basically not big. . This method can only estimate the voltage regulator tube whose voltage regulator value is less than the voltage of the high-voltage battery of the pointer meter. If the voltage stabilization value of the voltage regulator tube is too high, it can only be measured with an external power supply (from this point of view, when we choose a pointer meter, it is more suitable to use a high-voltage battery with a voltage of 15V than a 9V one).
