[ARC5] 24vdc power

[Tom Lee]

As a crude approximation, the reverse leakage of an ordinary silicon 
rectifier at room temp will typically be about 9 orders of magnitude 
below the forward current rating. So, a 100A rectifier can be expected 
to have a leakage current of perhaps 100nA. You may see larger numbers 
on datasheets, but those are generally sandbagged so that the 
manufacturer doesn't have to spend the money on actually testing that 
parameter.

Now, if you're still using seleniums or copper-oxide rectifiers, I might 
worry about the reverse leakage...otherwise, battery self-discharge will 
dominate by large factors.

--Cheers
Tom

-- 
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 9/5/2022 22:22, Brian Clarke wrote:
>
> Not a good idea, Bob.
>
> Some batteries, particularly lead-acid, see the pulsing DC as 
> charge-discharge cycles, shortening their lives. Diodes do not have 
> infinite reverse resistance; so, leaving a battery connected to a 
> transformer + rectifier combo will discharge the battery a bit faster 
> than shelf life.
>
> If you don’t use a battery or regulator to smooth out the pulses, your 
> outgoing radio signal will be modulated with 100 Hz or 120 Hz noise.
>
> 73 de Brian, VK2GCE
>
> *From:*Bob kb8tq [mailto:kb8tq at n1k.org]
> *Sent:* Tuesday, 6 September 2022 1:54 PM
> *To:* Brian Clarke
> *Cc:* Glenn Little WB4UIV; ARC-5
> *Subject:* Re: [ARC5] 24vdc power
>
> Hi
>
> If this is a basic “no regulation” supply ( = transformer driving 
> diodes into a load +
>
> (maybe) a cap …) the addition of a diode to isolate this or that does 
> nothing useful.
>
> Bob
>
>
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