12V Power Supply

[Jonathan Hutchins]

On Wednesday 24 September 2003 6:47 pm, KRFinch at dstsystems.com wrote:
> If you're careful, an automotive battery charger could be used as well.
> Most of those put out a rock-steady 12 volts at a low amperage, and they
> can be had pretty cheaply new, or even cheaper used.  Seems like any time I
> go into any pawnshop, there's one there for sale.
>
> I'd put a fuse in-line with whatever I was working on just to be safe, and
> test the output voltage before I started, but other than that it should be
> fine.  If you get one with variable amperage, I wouldn't start out using
> the "fast charge" setting until I was sure I needed the extra juice.
>
> Oh, and you can still use it as a battery charger... :)

Only problem with a battery charger is that they're very "noisy" - there's 
seldom any reason to smooth the output of the rectifiers, so you get nasty 
choppy 60HZ power with all kinds of harmonics.  You need that battery in the 
circuit to smooth it out so it doesn't fry something.

Of course, PC supplies have a 12V out!  Thanks, Duane!  That's the kind of 
"D'Oh!" answer I was after!