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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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18th May 2017, 9:11 pm | #1 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,007
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"Secondary Emission" valves.
I've always had an interest in the secondary-emission approach as a way to get extra gain in a valve - and it seems that various manufacturers tried it but largely failed to get it to work as a practical prospect.
http://www.r-type.org/exhib/aai0191.htm http://www.r-type.org/exhib/aaj0017.htm http://www.r-type.org/articles/art-023.htm The only place I can think of where "secondary emission" was a success was in photomultiplier tubes and some TV camera tubes. OK, some use of something akin to the "secondary emission" effect was also used as a way to nullify the space-charge in "12V-HT" car-radio valves in the 1950s but that always seemed to me to be rather different. Can anyone think of other examples of secondary-emission being used in real-world situations? |
19th May 2017, 2:49 pm | #2 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,833
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Re: "Secondary Emission" valves.
I had a pre-war TV that used the TSE4 valve although I can't remember which one it was now. I also had a spare or two of brand new, boxed valves. They were/are as rare as rocking horse droppings and Tudor Rees used to advertise them at mortgage level prices. So that's another application, TV receiving sets/equipment.
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A digital radio is the latest thing, but a vintage wireless is forever.. |
19th May 2017, 3:34 pm | #3 |
Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,511
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Re: "Secondary Emission" valves.
There's the 'giant acorn', type 1630.
It didn't have a long life, only about 50 hours before losing emission. So not very successful........... It looks nice, though, I have a couple of examples in my collection. Andy |
20th May 2017, 11:40 am | #4 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,007
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Re: "Secondary Emission" valves.
That's just so wonderfully crazy!
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22nd May 2017, 3:43 am | #5 |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
Posts: 4,203
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Re: "Secondary Emission" valves.
I think Philips used a secondary emission valve as a phase changer in one or two PA amplifiers, just before or just after WWII.
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