Can't identify and judge Zener diodes? Let's help
Zener diode is usually represented by "ZD" plus a number in the circuit, such as: ZD1 represents the number 1 Zener tube. Next, we will tell you how to identify the judgment diode.

Positive and negative identification
From the appearance point of view, the positive end of the metal-encapsulated Zener diode body is flat, and the negative end is semicircular. One end of the plastic-encapsulated zener diode tube with a color mark is the negative electrode, and the other end is the positive electrode. For Zener diodes with unclear signs, you can also use a multimeter to determine its polarity. The measurement method is the same as that of ordinary diodes, that is, use the multimeter R×1k file, connect the two test leads to the two electrodes of the Zener diode, and measure one After the result, adjust the two meter pens to measure again. In the two measurement results, the one with the smaller resistance value, the black test lead is connected to the anode of the Zener diode, and the red test lead is connected to the cathode of the Zener diode.

Color ring Zener diode identification
Color ring Zener diodes are rare in domestic products, most of them come from abroad, especially Japanese products. Generally, color ring Zener diodes are marked with models and parameters, and detailed information can be found in the component manual. The color ring voltage stabilizer diode is small in size, low in power, and mostly within 10V, which is very easy to break down and damage. The appearance of the color ring Zener diode is very similar to the color ring resistance, so it is easy to make mistakes. The color ring on the color ring Zener diode represents two meanings: one represents the number, and the other represents the number of decimal places (usually the color ring Zener diode takes one decimal place and is expressed in brown. It can also be understood as the magnification: ×10 (the -1 power), the number corresponding to the specific color is the same as the color ring resistance).

The difference between Zener diode and ordinary rectifier diode
First, use the multimeter R×1K block to judge the positive and negative electrodes of the tube under test. Then set the multimeter to the R×10K block, connect the black test lead to the negative pole of the tested tube, and the red test lead to the positive pole of the tested tube. If the reverse resistance value measured at this time is higher than the reverse resistance measured with the R×1K block It is much smaller, indicating that the tube under test is a voltage regulator tube; on the contrary, if the measured reverse resistance value is still large, it means that the tube is a rectifier diode or a detection diode.

The reason for this identification method is that the voltage of the battery used inside the multimeter R×1K block is 1.5V, and generally will not reverse the breakdown of the tube under test, so that the measured resistance value is relatively large. When the R×10K gear is measured, the internal battery voltage of the multimeter is generally above 9V. When the tested tube is a zener tube and the cut voltage value is lower than the battery voltage value, it will be reversed breakdown, making the measured value The resistance value is greatly reduced. But if the tube under test is a general rectifier or detector diode, no matter if the R×1K block is used for measurement or the R×10K block is used for measurement, the resistance value obtained will not be very different. Note that when the voltage value of the tested Zener diode is higher than the voltage value of the R×10K block of the multimeter, it is impossible to distinguish with this method.


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