That's pretty much where I started (except I put R2 on the NPN collector,
instead of the PNP base), but thought I could simplify it with one
transistor.  I hadn't realized the protection diodes would get in the way. 
I need to do this on 8 outputs simultaneously, so RA4 is not the full answer
here.

Cheers,
-Neil.



Bob Blick-4 wrote:
> 
> 
> On Wed, 11 Jun 2008 09:53:12 -0700 (PDT), "PicDude"
> <picdude2@avn-tech.com> said:
>> 
>> I need to switch on/off a 12V load, high-side, from a PIC running on 5V,
>> and
>> tried this circuit, but the output is always on.  With the PIC I/O
>> floating
>> (set as input), the load should be switched off, and with the I/O low,
>> the
>> load should be switched on.  I'm using 1k for R1 and 10K for R2.  The
>> load
>> will be up to ~250mA, btw.
> 
> Hi Neil,
> 
> On old 16C parts you do it with RA4 because the old process could
> tolerate the voltage. But you'll need to use an extra transistor to
> level shift. Attached is an example.
> 
> Cheerful regards,
> 
> Bob
> 
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