Quoting PicDude <picdude2@avn-tech.com>:

>
> 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.

Use Bob's method only. Eg.

R1 1K 1/4W
R2 10K
R3 6K8
NPN: 2N/MMBT4401
PNP: 2N/MMBT4403

In most cases you'll also want to add a diode or something similar  
across the load to tame inductive spikes, even for something like a  
nominally resistive load with long leads.

Best regards,
Spehro Pefhany
-- 
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