Zener Diode Tester

Zener Diode Tester

To find the rated voltage of a Zener diode, measure its voltage with a voltmeter or a multimeter (or simply just a voltmeter if you have one). The circuit is so simple that it may appear to be excessive to build the circuit into a component box. However, once you have it, it's one and done.

In order for this test to determine the Zener diode's rated voltage, we must feed power to the Zener diode in reverse bias in series with a resistor. The voltage must be higher than the rated Zener voltage of the Zener diode. In the circuit schematic provided, we feed the Zener diode and a 1KΩ resistor from a variable voltage power supply. For a Zener diode rated for 5.1V, we adjust the supply voltage upward until the output voltage stabilizes. At this point the voltage across the Zener diode will indicate the rated Zener voltage of 5.1 volts.

For this tester, I am using a variable power supply that supplies 3V to 24V DC which allows testing of Zener diodes within that ra