MadModder
The Shop => Electronics & IC Programing => Topic started by: russ57 on May 08, 2024, 09:14:19 AM
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This is in an elma antimag demagnetizer.
I think it is just a pair of diodes. But I'd like to be sure. It has 3 terminals and measures about 5Mohm both forward and reverse across each supposed diode.
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looks like some kind of rectum frier to me .
Have you a diode test setting on your multimeter? if so you should be able to read the forward voltage and check each diode.
Bill]
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I do, but it is effectively open circuit.
(ie, I think it is dead). Drawing out the circuit to make sure diodes make sense.
(not some odd scr or other complexity)
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Looks very similar to this full bridge rectum frier. But perhaps just a half bridge with 2 diodes.
https://www.ebay.co.uk/itm/124664837051 (https://www.ebay.co.uk/itm/124664837051)
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It's a half-wave rectifier.
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Yep, and to be precise it (was) a selenium rectifier...
I removed and opened it, to the accompanment of falling pieces.
So maybe it had failed, or maybe not, as measuring a stack of selenium junctions with a multimeter Does Not Chooch...
But from what I read of selenium if it wasn't dead, it was dying.
Replaced with 2 x 1n4007. All functional.
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(and for interest I traced the circuit and loaded it into an online circuit simulation. It is functioning as a voltage doubler, pretty much straight off the mains. Although I could not perform the necessary topology gyrations in my head to make it look like a doubler. Charges a big cap to 700odd volts which are then dropped across a coil.