Old bridge rectifier? - Page 1
Forum section: electronics / beginners

author: just5554
author_rank: Contributor
timestamp: June 21, 2016, 02:06:10 pm
content: Found in village, can someone tell me something? is it dangerous or something? maybe it's expensive? i dont understand russiannow i'm keeping it wraped in paper couse it fall aparthttp://www.155la3.ru/avs80_260.htm

author: rstofer
author_rank: Super Contributor
timestamp: June 21, 2016, 02:36:28 pm
content: It looks like a selenium plate rectifier.https://en.wikipedia.org/wiki/Selenium_rectifierSelenium isn't good for you so wash your hands after handling.https://en.wikipedia.org/wiki/Selenium_rectifierOr, maybe it is good for you but around here there is a lot of excitement about selenium being washed out of farm land and winding up in the rivers.

author: N2IXK
author_rank: Frequent Contributor
timestamp: June 21, 2016, 03:46:42 pm
content: I agree, selenium bridge rectifier. They were common before silicon diodes became available, but quickly became obsolete afterward. They had a high forward voltage drop, poor efficiency, and often gave off a terrible, toxic stench when they failed.Selenium is an essential trace nutrient, but quickly becomes toxic at higher levels.

author: Ysjoelfir
author_rank: Frequent Contributor
timestamp: June 22, 2016, 03:46:00 pm
content: That is definitely a selenium rectifier! And yes, they can smell really badly when dying.. Here in Germany some of us call them Selen "Gleich-riecht-er" which translates to selenium "soon-he's-going-to-smell".But I actually like them. Quite nice fiddling around with - have a go!

author: karoru
author_rank: Regular Contributor
timestamp: June 22, 2016, 04:47:46 pm
content: To be honest most of funky smell emergencies were coming from small rectifiers found in radios, TVs and so on. Big ones weren't that bad, I've seen many car battery chargers made using selenium rectifiers still alive and kicking after >50 years of use - most problems with them comes from rust on connectors or being a bit on the zappy side because of exposing them to rain. All these 'smart, intelligent and good in bed' chargers nowaday will probably desolder themselves, borrow money from your wallet and take a cab to electro-dump facilities long before that.

author: N2IXK
author_rank: Frequent Contributor
timestamp: June 22, 2016, 05:33:26 pm
content: IIRC, older battery chargers used copper oxide rectifiers rather than selenium, because of the lower forward voltage drop. They looked quite similar to the selenium units, though.

author: just5554
author_rank: Contributor
timestamp: June 22, 2016, 05:51:27 pm
content: Quote from: karoru on June 22, 2016, 04:47:46 pmbut nowadays compare sizes of 4x1n4007 and selenium b.r. we can see big difference, and ofcourse i think it's way easier to make bridge rectifiers now.

author: jitter
author_rank: Frequent Contributor
timestamp: June 22, 2016, 06:43:08 pm
content: Hmm, it says the lifetime is "at least 2000 hours". That's not very much, is it?That reminds me: we saw one in a different shape in the last Mailbag episode (#888):https://youtu.be/VKJ1h6ThW3Y?t=1062.

author: karoru
author_rank: Regular Contributor
timestamp: June 22, 2016, 07:35:02 pm
content: Quote from: N2IXK on June 22, 2016, 05:33:26 pmInteresting, they tended to be advertised as 'selenium', but probably anything that lookslike central heating radiator would be marketed at automobile market as selenium no matter if it's oxide type or an actual selenium. I don't have any at home at the moment, I should investigate when I visit my family:)Just5554 - 1N4007 is 1A diode, it would melt when used to charge your usual 50 Ah car battery;)After era of plate rectifiers people started to use these "spark-plug lookalike" diodes, which stillcan serve well for throwing it at people with intention of inducing blunt trauma.