How do i check if the diode is working?

Question

How do i check if the diode is working?

Answer 1

"To test out a diode, first you will  have to set your digital multi meter to the diode  setting, which is usually part of the Ohms (resistance) section on the meter.

If you are using an analog meter, then set it to the lowest Ohms Ω setting.

You should disconnect at least one side of the diode if it is still in the circuit. First check resistance across the diode, then check again but swap your leads to the opposite side they were on for the first reading. If you get an open (meter doesn't move) one way, but some kind of reading the other way, then the diode is good. If you get a reading (meter moves) both ways, then the diode is shorted. If you get an open (no movement) both ways, then the diode is open. "

I got this from:  http://www.ohmcheck.com

Hope this helps you.

Answer 2

In circuit - not entirely reliable, but you can measure the voltage across a rectifier diode with power on. With a meter that reads true DC and AC (some will read DC volts in the AC setting, no good) you should have a DC voltage and an AC voltage across a working single rectifier diode - not in a bridge, that will not correctly show an open diode. A single open diode will only show AC with no DC, a shorted diode will have no voltage AC or DC.

You cantry and measure the resistance or diode voltage across the diode with power off, but associated circuitry can confound this. Generally a good diode will settle at fairly low resistance or at about 0.5V forward, and high resistance or "error" or a slowly rising reverse voltage above 1 volt as connected capacitors charge.

The best way is to remove it from the circuit. AN ohmmeter will show infinite or very high resistace connected one way, reverse the leads and you should get low resistance. A digital meter with diode check will read volts, one way should be about 0.5V and the other should read "error" or something similar saying there's no connection between the test leads. high resistance or "error" both ways, zero ohms or volts both ways,, or one way fairly low and the other higher but still fairly low... all mean bad diode.