On Sun, 07 Jan 2018 18:22:53 +0000, Max Demian wrote:

On 07/01/2018 17:19, Cursitor Doom wrote:
On Sun, 07 Jan 2018 15:41:16 +0000, Johnny B Good wrote:

Thermionic valves (vacuum tubes) are pretty robust devices. even if
the
anode rail is hit by a massive voltage spike, enough to cause a flash-
over and melt a hole in the anode plate, they'll often continue to
function with no perceivable drop in performance (unless it's a
*really big* hole in the anode plate).

There's a book out somewhere (been meaning to get a copy for years)
where the author explains how you can make your own valves. Think it's
called 'desert island electronics' or 'post-armageddon radio' or
something like that. PW list it in their adverts section quite
regularly.

Why not make your own semiconductors? After all, galena is naturally
occurring.

You can create a point contact transistor with a great amount of care
(and lots of expletives as you try to find *two* sweet spots) as a "Proof
of Concept" exercise. The results won't be pretty or robust or offer much
gain, although the transistor produced is almost certainly going to show
a very high noise level, if it works at all.

Making your own vacuum tube (thermionic valve) is more likely to produce
a robust and usable device, given enough ca

https://www.youtube.com/watch?v=oSgVGwqJ2Jk

--
Johnny B Good

On Monday, 8 January 2018 02:34:38 UTC, Cursitor Doom wrote:
On Sun, 07 Jan 2018 19:05:06 +0000, Terry Casey wrote:

When they ran out of 13A fuses, the trusty foil from a ciggy packet had
been used.

Back in the 1960s I used to use milk bottle tops; they were a bit more
substantial.

A single strand of extraflex has made many a fuse


NT

On Mon, 08 Jan 2018 01:56:08 +0000, Johnny B Good wrote:

You can create a point contact transistor with a great amount of care
(and lots of expletives as you try to find *two* sweet spots) as a
"Proof of Concept" exercise. The results won't be pretty or robust or
offer much gain, although the transistor produced is almost certainly
going to show a very high noise level, if it works at all.

I remember making a junction diode as part of a first year lab at
university!

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Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

In article ,
Bob Eager wrote:
You can create a point contact transistor with a great amount of care
(and lots of expletives as you try to find *two* sweet spots) as a
"Proof of Concept" exercise. The results won't be pretty or robust or
offer much gain, although the transistor produced is almost certainly
going to show a very high noise level, if it works at all.

I remember making a junction diode as part of a first year lab at
university!

Cat's whisker?

--
*Suicidal twin kills sister by mistake.

Dave Plowman London SW
To e-mail, change noise into sound.

On Mon, 08 Jan 2018 11:06:44 +0000, Dave Plowman (News) wrote:

In article ,
Bob Eager wrote:
You can create a point contact transistor with a great amount of
care
(and lots of expletives as you try to find *two* sweet spots) as a
"Proof of Concept" exercise. The results won't be pretty or robust or
offer much gain, although the transistor produced is almost certainly
going to show a very high noise level, if it works at all.

I remember making a junction diode as part of a first year lab at
university!

Cat's whisker?

No, a *junction* diode. Melting an indium bead into a piece of germanium.

--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

On Monday, 8 January 2018 11:58:36 UTC, Bob Eager wrote:

I remember making a junction diode as part of a first year lab at
university!

Cat's whisker?

No, a *junction* diode. Melting an indium bead into a piece of germanium.

I got to make a Josephson junction in a practical. That was a cat's
whisker of sharpened, oxidised niobium wire pressing against a niobium plate.

John

On Mon, 08 Jan 2018 01:49:34 +0000, Johnny B Good wrote:

There's a nice 4 part series about making a Lee de Forest Audion triode
valve (vacuum tube) by Ron Soyland on YouTube which describes all of the
construction steps in great detail.

https://www.youtube.com/watch?v=oSgVGwqJ2Jk

takes you to the first episode.

Yes, valves you make yourself are a much more worthwhile pursuit than
semis. If I ever get the time some day I'd like to give it a bash.



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