My sent messages shows the pdf file sent.
Dan
On Friday, January 10, 2025 at 12:48:56 PM EST, F1CHF via groups.io <f1chf@...> wrote:
hello
where is the file ?
tks
Le 10/01/2025 6:45 pm, Dan Kahn via groups.io a ¨¦crit?:
Here is a schematic I reverse engineered.
On Friday, January 10, 2025 at 11:01:52 AM EST, Roy J. Tellason, Sr. via groups.io <roy@...> wrote:
?
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On Friday 10 January 2025 09:53:33 am wn4isx via groups.io wrote:
> In your circuit, the NiCad and LED would normally limit the voltage, although you can easily cook a NiCad to death with 24/365 charging at as low as 1/20 C (C being amp hour) and N cell NiCads have a very low amp hour rating. I suspect it'd be extremely easy to cook them to death.
Yeah,? there is that.? I have a Simpson DVM that uses four fat nicads to power it,? and I'm on my second or third set of them so far.? And they're not in good shape.? The original charger for that was a wall wart that was supposed to put out 7.5V,? fed through a resistor and that's it.? I also have a cordless screwdriver that sits in its stand most of the time,? with three nicads in it,? and they're not holding a charge all that well these days either.
> I'd be tempted to use a wall wart and build a real regulated power supply. The circuit you describe is simple, maybe too simple to be reliable.
I've pretty much given up on using nicads these days,? but if I did I think I'd prefer to use a circuit that would stop charging them at a given point,? coming back on only when needed.? Like those TP4056 modules I use for the lithium cells...
--
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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