Thanks for your replies everyone :)  I think I'll build a thingywotsit
socket for use with a "walwart" (must be an American term!..).  My brain
tells me that a 7805 regulates to 5V, so a 7812 will regulate 12V.. is it
lying?  Also, what would I actually have to get from the wallmart (above the
12V)?

Ta
Kieren and his Fish

----- Original Message -----
From: "M. Adam Davis" <adampic@UBASICS.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Friday, July 26, 2002 9:53 PM
Subject: Re: [PIC]: 12V supply for programmers


> You should be able to get current/voltage curves for this device from a
> few different battery manufacturers.
>
> The 12V value is known as the 'nominal' voltage, and the actual voltage
> before discharge may be as much as a volt or two higher.
>
> If you can't get a dischare curve, then put the battery under load and
> measure it every so often to see how much current you can draw for how
> long before it drops below the necessary programming voltage.
>
> Chances are good that you won't be able to run the whole programmer from
> it, but if you use it with a 4AA supply (4AA for the rest of the
> programmer, 12v for the MCLR) then you shouldn't have any problems.
>
> IIRC, most pics have a recommended programming voltage of 13.5 for MCLR.
>  The ICD (original) documents has a simple PWM controlled voltage
> tripler that uses a few transisters, coils, diodes, etc for its
> programming voltage.  I would suggest you spend the extra doller for a
> handful of parts and derive the programming voltage from your other
> power supply (4AA, maybe.)
>
> -Adam
>
> Kieren Johnstone wrote:
>
> >Hi,
> >Just wondering, will a small 12V alkaline battery (it's about AA size) be
OK for a 12V source for use in a PIC programmer - PARPIC, for example.  Or
should I go for the 8xAA (or 10xAA rechargable - they're only 1.2V!)?  Or a
car battery? :(
> >
> >Thanks,
> >Kieren Johnstone
> >
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