APT Electronic industries LTD Model 503 500V regulated power supply

[Denis G4DWC]

This 1953 advertisement may be of interest.

I'm not sure where I got it from but it gives details of the range, apart from mine of course!

Later adverts may have included mine.

One thing I was surprised at, since looking at the posted circuit, was the use of tiny Hivac XFW40 wire ended battery valves V6 and V11. Not the sort of thing you normally expect in something like this brute.

Denis

[GrimJosef]

Originally Posted by Cowasaki

Because selenium is toxic and can cause death in relatively small amounts!

As I understand it selenium release from a rectifier only occurs in the event of catastrophic failure. This is sudden, and the infamous powerful stink as well as the failure of the supply alert you to it immediately, so there's no realistic prospect that you'll be ingesting it without being aware.

I don't think there's a history of people coming to known harm over the years that these things were in quite widespread use. And selenium isn't hugely toxic. It's a required trace element for good health, after all, and we consume it in our diet. It's just overdosing that can be the problem.

Cheers,

GJ