开云体育

On Sunday 03 November 2024 01:31:59 pm wn4isx wrote:

I'm posting these to give people ideas on practical experiments.
This was fascinating, a introduction to physics teacher taught me this trick in high school

I hadn't really thought of CdS as a semiconductor...

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
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Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin

On Sunday 03 November 2024 07:36:27 pm Andy wrote:

If I'm not mistaken, these days CdS photocells may be hard to come by.? They are toxic (HIGHLY toxic, I am told) and I think have been banned for a while now in most parts of the world.

Bummer.

They still seem to be fairly reasonably obtainable from various chinese sellers, on ebay, etc.

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin

On Sunday 03 November 2024 08:25:26 pm wn4isx wrote:

[1KV CDS cells? Say it ain't so. I use them for V+ or Vgnd to base <I tend to use NPN transistors>, even 120V frightens me silly!]

I seem to recall a part that was popular back when, called the "LDR-25", the letters standing for Light Dependent Resistor. And the numbers meaning that the thing could dissipate 25 watts? There were some projects with that thing running off of line voltage. Look in Popular Electronics "Solid State" or "Transistor Topics" (earlier) for these.


--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin

On Monday 04 November 2024 04:44:27 pm wn4isx wrote:

Speaking of things that have gone away, I miss unijunctions. I have about 2 dozen and pick projects for them with great care. PUTs suck bilge water on a good day.

What do you have against PUTs?

I think I may have one UJT, I ran across something and just looking at it I was thinking about picking up some of those. You can do a pretty good simulation of them with a cross-connected complementary pair. Use that as an SCR, SCS, PUT, all sorts of ways. Not sure if you could make it act like a Schockley diode or not, though.

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin