> limited current.  Is it a good idea to put some sort of electrical
> "fusing" between a regulated 5 volt power supply and the PIC input
> pin(s)?  (There is a 3 Amp circuit breaker in the upstream 12-16 volt
> power supply that I regulated down to 5 volts.)  Would it serve to
> protect the PIC, associated components, and possibly safety?

As someone said, the PIC is quite hardy, though two common situations where
you could have it really draw too much current would be overloading the port
outputs, or inserting the PIC upside down. For the latter situation, a
"fool's diode" (as Wouter affectionately calls it) would be much simpler
(i.e., reverse-biased).

I don't think you'd find standard fuses at such low ratings (5V/500 mA, for
instance). You may want to look in the National 7805 datasheets...I believe
they have schematics for a current-limited regulator.

IMHO, once you are comfortable with PICs, a fool's diode should be all the
protection you need -- PICs are hardly little things, mine usually even
survive reverse-insertion so long as I switch it off <2-3 seconds after
power-up.

Cheers,
Ishaan

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