I'm trying to debug a broken welder, and I see that there's a (4 diode bridge) rectifier circuit that is no longer working. I'm at home with a multimeter trying to figure out where the problem is. I found this on-line, but this is basically the circuit:
The fact of the matter is that it was working when I was debugging another issue and I shorted something and broke the rectifier. The AC is coming in from a transformer and was about 20 volts. I was measuring DC voltage at the output, but now am only seeing AC. The cap "seems" okay in that it is not shorted, and I can watch resistance readings go up and down from the charge coming from the multimeter.
The thing I can't explain is that all four diodes read open in one direction, and about 500 ohms the other. I expected them to read almost no resistance in the forward direction. Does it makes sense that good diodes would have so much resistance? Blowing them all to the same state seems improbable.
Thanks for any help.
The fact of the matter is that it was working when I was debugging another issue and I shorted something and broke the rectifier. The AC is coming in from a transformer and was about 20 volts. I was measuring DC voltage at the output, but now am only seeing AC. The cap "seems" okay in that it is not shorted, and I can watch resistance readings go up and down from the charge coming from the multimeter.
The thing I can't explain is that all four diodes read open in one direction, and about 500 ohms the other. I expected them to read almost no resistance in the forward direction. Does it makes sense that good diodes would have so much resistance? Blowing them all to the same state seems improbable.
Thanks for any help.