At 15:44 11/10/99 PDT, you wrote: >Of course, if you connect up your 100V supply through your 1M resistor >to a PIC input pin, and then measure the voltage at the pin, you WILL >read Vcc+0.6V or so, assuming that the internal protection diodes are >functioning... > >BillW > > Not quite so, This will be so only after the diode (Transistor) has begun conduction. Until this point the pin may be way way over voltage. Dennis