Re: 9VAC from 5VDC?

From: Jim Brain <>
Date: Mon, 16 Sep 2013 17:05:03 -0500
Message-ID: <>
On 9/16/2013 4:10 PM, Bil Herd wrote:
> Given how cheap a 9VAC wall-mount transformer I, why would it not be
> better than a 5VDC-9VDC convertor?  Also the 5v supply would need to
> handle an addition 1.25 Amps at a guess, what is the 5V supply in this
> case?
FYI: On AC, I think the CIA uses the 60 Hz wave to clock the TOD. (50 in 
some other countries).

I will admit I posted my earlier comment before looking at the cost of 
the transformer alone in the design.  I was expecting $4-8, and the 
$24-$30 caught me by surprise.

Yeah, at that price, it gives pause.

On amperage, I was thinking it would need to source another 2.5A at 5VDC 
to make all this work (7.5VA into the transformer would provide ~.8A @ 

My thinking was that folks could readily leverage all of the cheap 5VDC 
laptop power supplies around, passing the 5V through and just creating 
this additional voltage using the circuit.  Others could run the design 
off a 6V DC battery (the difference is minimal) and then we'd have a 
portable C64, and I could make my SX portable by using such a circuit 
and replacing the CRT with an LCD (1541 would be doable with a 12V 
battery made up ot 2 6V cells, which could give 12V and 5V.

But, I doubt most will want a $30.00 transformer.

Probably not a huge market for such an expensive item.


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Received on 2013-09-16 23:00:02

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