The horrible failure mode of selenium rectifiers

Clive, can't you pleeeeease blow one up and smell it again in a video? I really enjoy most of your videos but I can sincerely say that among the most best videos from an entertainment point of view, are when you the crazy stuff like tasting denaturated alcohol, tasting weird "viagra" capsules that are so bitter that you even curse out of disgust. And the best one - when you smelled the fart aroma from the South Park smell generator, I laughed so much I think I passed out for a brief moment. You always share us viewers so many good laughs at your own expense it´s hard not to love you :)

IMHO, it smells WORSE than a fart, at least the smell of a fart goes away fairly quickly. I used to buy Radford Labpacks off eBay - we used them as battery chargers etc - and the first thing done was replace the low-tension selenium rectifier with a big, beefy silicon one (and disable the 300VDC, swap out the magnetic cut-out for a thermal one etc.). I did a few of those, listed the old rectifiers on eBay and they always sold, so plenty demand for electric fart generators..

Gordo

Surely the "Radio Spares" name became the "RS Components" we know today? Oh yes, so it did! https://uk.rs-online.com/web/generalDisplay.html?id=aboutRS

Stephen Eyles

That's why the old techs often put a series resistor in after replacing one with a silicon diode or bridge. It reduced the B+ back to original design levels.

George Cohn

I just watched shango066 pick one of these from an estate clearout!

😄😂

The series resistance reduced the current surge into the smoothing capacitor. Replacing them with silicon rectifiers after they'd farted often resulted in other components failing. Don't ask me how I know ;-)

Plenty of them on old radio and television transmitters of the analog flavour. I used to keep a can of Febreze in the trunk for such occurrances. When replacing with modern rigs, we had to retap the power transformer primaries to account for the different voltage drops. You got this one bang on!! I hope to never smell another!! Ugh, disgusting!!

Chuck Kirchner

Agreed. I wonder why? Silicon's not that new.

Mike Page

I'm a little disappointed that you didn't blow one up (outside, of course!) but maybe that'll be something to look forward to in the future.

Circuitmike

When I was a kid the local flats had Express Lifts (elevator) and the control box had big ones of those. I was tipped off by the caretaker and I remember the day the engineer changed the failed rectifiers for big "meaty" diodes. I remember the smell. Proper electromechanical contactors and relays with a thermionic valve.

Nuts 'n' Proud

in some tube radios of the late fifty's and sixes had selenium rectifiers

richard ockman

It's definitely quite dramatic, but these days a lot of electronic stuff fails in the same visual way.

Big Clive

Yes, they do them in circular versions too.

Big Clive

It's my favourite pen, but seems to go under different names in other countries.

Big Clive

I've got an old VTVM with a selenium rectifier in it. Happily, it's not been blown. Yet.

Brendan Meteer

Very interesting video Clive. Maybe set up some small bottles to collect a portion the ‘stench’ and fire one off (rectifier, not fart) in a controlled manner. You could then sell the bottled stench for people to experience it themselves (or give some to random Patreon’s)?

Simon York

Its a long time since I saw on of those. When I first studied electronics in 1969 our lecturer showed us one. He recommend the new block rectifiers for the valve radios we were building.

Jeremy Travis

The teachers smoked pipes and fags around the classrooms in my day too, and also had a great sense of humour when it came to lab experiments.

Andrew Donaldson

In the early 1970s our math teacher at school (in DK) "thought" us, as a party trick, to put a small piece from a selenium rectifier in the bottom of a smoking pipe. Of course he strongly warned us never to do it. He was a pipe smoker himself. He always came into the classroom with a pipe in his mouth, put his papers on his desk, went to open the window and blew the last puf of smoke out the window and left the pipe on the edge of his table) We had great teachers in those years, and we learned a lot of naughty stuff :-) We did also learn some good maths in his classes.

Zeedijk Mike

Until quite recently (about 20 years ago) selenium rectifiers were still used in car battery chargers.

Dave Davies

* tape delay effect on * FULL WAVE BRRRIDGE RECTIFIER - FAAYA - FIRE * tape delay effect off *

Frank

I think if one of those shot phlames while I was around, I too would make a similar smell.

Dr Andy Hill

I remember these inside devices when I was young. sometimes they were circular plates too, or is my memory fooling me.

Dr Andy Hill

Pilot should sponsor your vldeos. You're always using their pens in them.

Gadgetman

Selenium rectifiers are also commonly found in the old (pre-1980"s) car battery chargers.

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