Testing bridge rectifier

[johnnydiaz]

Is this the best way to test a bridge rectifier?

http://www.youtube.com/watch?v=11JPy4t36oo

[mariushm]

Re: Testing bridge rectifier

A bridge rectifier is simply 4 diodes arranged like this:



Each diode is supposed to have a forward voltage in one direction only, so on diode mode, if you measure with the probes one way you get the voltage drop shown on screen , if you invert the probes you should get nothing.

You have


DC - ─►|─ AC 1
DC - ─►|─ AC 2
AC 1 ─►|─ DC+
AC 2 ─►|─ DC+


So:
red on DC- , black on AC 1 and AC2 and you should have 0.4-1.2v both times. Invert probes, nothing.
black on DC+, red on AC1 and AC2 and you should have 0.4-1.2v both times. Invert and you should have nothing.
Basically like he says, but in less confusing way. And DO NOT test the rectifier while the power supply runs!

Depending on current the bridge is rated for, the voltage shown will vary. Regular diodes are around 0.5-0.6v but high current rectifiers can show up to around 1.2v

[johnnydiaz]

Re: Testing bridge rectifier

Can I test a BR in circuit or do I have to remove?

[budm]

Re: Testing bridge rectifier

I always test it out off the circuits.