# How to test the breakdown voltage of TVS diode

**URL:** <https://forum.digikey.com/t/how-to-test-the-breakdown-voltage-of-tvs-diode/999>\
**Category:** Circuit Protection\
**Tags:** tech-tips, circuit-protection, power\
**Created:** [December 20, 2017, 6:00am UTC](https://forum.digikey.com/t/how-to-test-the-breakdown-voltage-of-tvs-diode/999 "2017-12-20T06:00:00Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Barley\_Li](https://sea2.discourse-cdn.com/digikey/user_avatar/forum.digikey.com/barley_li/32/558_2.png) [@Barley\_Li](https://forum.digikey.com/u/Barley_Li)\
**Post date:** [December 20, 2017, 6:00am UTC](https://forum.digikey.com/t/how-to-test-the-breakdown-voltage-of-tvs-diode/999/1 "2017-12-20T06:00:00Z")

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When testing the breakdown voltage of [TVS diodes](https://www.digikey.com/en/products/filter/tvs-diodes/144), there is an easy way to discover this parameter for yourself.

Set up a circuit per the following drawing. Then, gradually adjust your Vaa voltage via the power supply. Use a universal meter or [DMM](https://www.digikey.com/en/products/filter/equipment-multimeters/615) to test the voltage across D1, as shown. When the D1 voltage stops following the increase in Vaa voltage, this voltage should be your TVS breakdown voltage.

![Test](https://global.discourse-cdn.com/digikey/original/2X/9/97ce818837a8ac9d49d7dd40478908d4dde8db62.JPG)