Will not recognize the judgment of the Zener diode? We come to the trick

Positive and negative polarity recognition

From the appearance, the positive end of the metal-packed Zener diode body is planar, and the negative end has a semi-circular shape. One end of the plastically sealed diode body printed with a color mark is a negative electrode, and the other end is a positive electrode. For the Zener diode with unclear mark, it can also be judged by the multimeter. The measurement method is the same as that of the ordinary diode. That is, the multimeter pen is connected to the two electrodes of the Zener diode by the multimeter R×1k file, and one is measured. After the result, the two meter pens were measured. In the two measurement results, the resistance value is smaller, the black meter is connected to the positive pole of the Zener diode, and the red meter is connected to the cathode of the Zener diode.

Color ring regulator diode identification

Color ring voltage regulator diodes are rare in domestic products, most of them from abroad, especially Japanese products. General color ring regulator diodes are marked with the model and parameters. Detailed information can be found in the component manual. The color ring voltage regulator diode is small in size, low in power, and the voltage regulation value is mostly within 10V, which is easily broken down and damaged. The appearance of the color-coded diode is very similar to the color ring resistance, making it easy to make mistakes. The color ring on the color ring regulator diode represents two meanings: one is the number and the other is the decimal point (usually the color ring regulator diodes are all one decimal, expressed in brown. It can also be understood as the magnification: ×10 (the -1 power), the color corresponding to the color of the same color ring resistance).

The difference between Zener diode and common rectifier diode

First, use the multimeter R × 1K block, and judge the positive and negative electrodes of the tube to be tested. Then dial the multimeter to the R×10K block, the black pen is connected to the negative pole of the tube, and the red pen is connected to the positive pole of the tube. If the reverse resistance measured at this time is lower than the reverse resistance measured by R×1K block. A lot smaller, indicating that the tube under test is a Zener tube; conversely, if the measured reverse resistance value is still large, the tube is a rectifier diode or a detector diode.

The reason for this identification method is that the battery voltage used inside the multimeter R×1K block is 1.5V, and generally the reverse breakdown of the tube to be tested does not cause the measured resistance value to be relatively large. When the R×10K block is measured, the voltage of the internal battery of the multimeter is generally above 9V. When the measured tube is a Zener tube and the cut-off voltage is lower than the battery voltage value, it is reverse-punched, so that the measured value is obtained. The resistance value is greatly reduced. However, if the tube to be tested is a general rectifying or detecting diode, the measured resistance will not be very different regardless of whether it is measured with R×1K or with R×10K. Note that when the voltage regulator value of the measured Zener diode is higher than the voltage value of the multimeter R×10K block, this method cannot be distinguished.