Photo-zener diode tester-with 6V zener diode

This is a circuit to test zener diodes. It hooks up to a 120V AC line and boosts the output voltage to over 300V allowing you to test zener diodes of any voltage. The circuit also has a push button switch to triple the current, if needed. The output is attached to 2 pairs of alligator clips. One pair is to attach to the diode. The second pair is to attach to a multimeter. The voltage across the diode is show on you multimeter.


It should be noted that this circuit could be dangerous. It is tied directly to an AC line, and has an output of 300V. The output has resistors on each line, which limits the current making it a bit safer, but will still give you quite a shock.

It should be switched off while attaching and removing the zener diode



Circuit-schematic-zener diode tester

Photo-zener diode tester-internal circuit


to be added

Photo-zener diode tester-with 6V zener diode
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