I have tried the recommended brownount protection circuit p. 2-415 in
the PIC microcontroller databook.
I used a 2N3906 for the pnp transistor and a 3.9v zener diode for
a cutoff at 4.6v. I tried it without the PIC and monitored the output
voltage. There was no switch in logic state on the output when I dropped the
supply voltage, only a linear drop. I even tried other pnp transistors
and even npn transistors and switching connections of the emmitter and
collector. No luck. Does anyone know of a SIMPLE circuit that will
do the same thing or indicate what I may be doing wrong?

                Neil Gandler