Pull up on what mosfet pin and to what? +5 or +12? Problem is if it must be
+5, the voltage regulator that regulates the +12 down to +5 isnt even alive
till after the mosfet is turned on. Also this has to be pulled down by a
PIC i/o pin. If its pulled to +12, can a PIC i/o pull it to ground?

Tim Thompson

At 08:17 AM 8/3/2001 -0300, you wrote:
>It's a P-Channel Mosfet. I did not see the diagram, but it must have a
>pull-up resistor to ensure proper turn-off.
>
>Marcelo Y.
>
>Roman Black wrote:
> > Tim Thompson wrote:
> > >
> > > Hello all, once again,
> > >
> > > I'm attempting to make a PSU based off the attached schematic. The
>problem
> > > I'm having is the MOSFET wont turn off.
> > > Its allways 'on'. As soon as +12 is applied the circuit comes alive,
> > > regardless of the state of its Gate. Pull it high or low and its still
>on.
> > > The MOSFET I'm using is a MTP2P50E, its made by Motorolla and its
>datasheet
> > > can be found on www.onsemi.com, just search for that PN.
> > >
> > > Anyway if anyone has any suggjestions, lemmy know.
> >
> >
> > Hi Tim, your circuit misses the important bit.
> > The bit that drives the FET. :o) Your circuit
> > also says 1.5v where I think you mean 12v?
> > And is your FET an N type or P type device?
> > -Roman
> >
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> >
> >
>
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