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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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11th Feb 2019, 12:23 pm | #1 |
Octode
Join Date: Nov 2003
Location: Bath, Somerset, UK.
Posts: 1,806
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Old selenium rectifiers
I have a quantity of old selenium rectifiers. Is there a way of testing them to see if they are worth keeping or should they be assumed too old to use and be disposed of. They may be good to "fill a hole" to maintain originality using a silicon by-pass, but better to be actually used if possible.
Neil
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preserving the recent past, for the distant future. |
11th Feb 2019, 12:39 pm | #2 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 4,108
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Re: Old selenium rectifiers
As an example i bought an elderly battery charger with 12v/6v/2v tappings, and a big green painted selenium rectifier. We 'scoped the output and it was a perfect full wave rectified trace, such that it was put straight into service. I think that very many of them will be ok. If they look uncorroded suggest energising them, and using a 'scope. If they start to smell switch off and ventilate the room!
Dave |
11th Feb 2019, 12:54 pm | #3 |
Dekatron
Join Date: Aug 2013
Location: Wigan, Greater Manchester, UK.
Posts: 9,433
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Re: Old selenium rectifiers
I thought battery chargers used copper oxide rectifiers due to being more suitable for low voltage high current. Probably replaced by silicon now.
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Frank |
11th Feb 2019, 12:55 pm | #4 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,970
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Re: Old selenium rectifiers
I don't think it's worth trying to use them in anger, though as you say they might have a cosmetic use.
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11th Feb 2019, 12:57 pm | #5 |
Octode
Join Date: Dec 2017
Location: Morden, Surrey, UK.
Posts: 1,561
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Re: Old selenium rectifiers
The big old ones with fins may be copper oxide, not selenium - and basically, if they work under load fair enough. Not so keen on the small contact cooled types though - they`ll certainly fail sometime soon.
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