How to Identify Zener Diodes

How to Identify Zener Diodes

Zener Diodes are commonly used in circuits to indicate "ZD" with numbers, such as ZD1 indicating a voltage regulator with number 1.

Positive and negative pole identification

From the appearance, the positive end of the metal encapsulated voltage regulator diode body is planar, and the negative end is semicircular. One end of the plastic sealed voltage regulator diode body printed with a color symbol is the negative electrode, and the other end is the positive electrode. For voltage regulator diodes with unclear markings, a multimeter can also be used to determine their polarity. The measurement method is the same as for general diodes, which is to use a multimeter R × At 1k level, separate the two probes from the two electrodes of the voltage regulator diode, measure one result, and then adjust the two probes for measurement. In the two measurement results, the one with the smaller resistance value, the black lead is connected to the positive pole of the voltage regulator diode, and the red lead is connected to the negative pole of the voltage regulator diode.

Identification of color ring voltage regulator diode

The domestic products of color ring voltage regulator diodes are rare, with the majority coming from abroad, especially Japanese products. Generally, color ring voltage regulator diodes are labeled with their types and parameters, and detailed information can be found in the component manual. The color ring voltage regulator diode has a small volume, low power, and a voltage stabilization value mostly within 10V, making it highly susceptible to breakdown and damage. The appearance of the color ring voltage regulator diode is very similar to the color ring resistance, so it is easy to make a mistake. The color ring on the color ring zener diode represents two meanings: one is to represent numbers, and the other is to represent the number of Decimal separator (generally, the color ring zener diode takes one decimal place and is indicated in brown. It can also be understood as magnification, namely: × 10 (to the power of -1), with detailed color corresponding numbers corresponding to the same color ring resistance

Zener Diodes The difference between a voltage regulator diode and a general rectifier diode

First, use a multimeter R × 1K gear, press to distinguish the positive and negative electrodes of the tested . Then set the multimeter to R × On the 10K gear, connect the black lead to the negative pole of the test , and the red lead to the positive pole of the test . If the measured reverse resistance value at this moment is higher than using R × The reverse resistance measured at 1K gear is much smaller, indicating that the measured  is a voltage stabilizing ; On the contrary, if the measured reverse resistance value is still large, it indicates that the transistor is a rectifier diode or a detector diode.

The reason for this identification method is that the multimeter R × The battery voltage used inside the 1K gear is 1.5V, and generally does not reverse breakdown the measured , resulting in a relatively high resistance value. And R × When measuring at 10K gear, the voltage of the internal battery of the multimeter is generally above 9V. When the measured  is a voltage stabilizing  and the voltage value is lower than the battery voltage value, it is reverse breakdown, greatly reducing the measured resistance value. But if the tested  is a general rectifier or detector diode, then regardless of the use of R × 1K gear measurement still uses R × When measured at 10K, the resulting resistance values will not differ significantly. Note that when the voltage stabilization value of the tested voltage regulator diode is higher than the multimeter R × When the voltage value is at 10K gear, it is impossible to distinguish it using this method.