Automatic Zener Diode Tester

299

05:08:47

Close switch to operate and read value off voltmeter or oscilloscope. The transistors form a constant current circuit which ensures the device under test (DUT) is not harmed. With the supply voltage at 30V this circuit can be used to check zener diodes up to 20V.

Note that EC zeners have a knee current of 13.6mA. I have chosen quite a low current here so that devices are not damaged but irl you may want to change it to match, or be closer to, the published data for your particular zener.
This circuit is intended as a quick go/no go test.
You can also test ordinary diodes by inserting the DUT the other way around.

published 5 years ago

PrathikP

5 years ago

"Note that EC zeners have a knee voltage of 13.6V." it's current, not voltage. 13.6mA is the knee current

Robert_Kidd

5 years ago

Absolutely right. I should have read it back before posting. Correcting it now.

digital_electronics

5 years ago

Good to see you publishing circuits again Robert. The atmosphere has improved dramatically since certain members decided to move on, keep the circuits coming my friend...👍

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