Yup, It worked fine.  It is still in the prototype and keeps on a tick'n.




----- Original Message -----
From: Richard Prosser <RPROSSER@SWICHTEC.CO.NZ>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Monday, May 31, 1999 6:58 PM
Subject: Re: Reverse Polarity Protection for 3V PIC Circuit.


> But did it work again afterwards????
> Richard
>
> > -----Original Message-----
> > From: David Covick [mailto:dac@WEST.NET]
> > Sent: Tuesday, June 01, 1999 1:55 PM
> > To: PICLIST@MITVMA.MIT.EDU
> > Subject: Re: Reverse Polarity Protection for 3V PIC Circuit.
> >
> >
> > Tony,
> >
> > I just finished a project that uses 4 AA batteries.  At over
> > 6 volts, I
> > applied the voltage backwards for maybe 2 minutes or more.  I
> > wondered why
> > my start-up beeps did not sound and just what went wrong.  I
> > checked my
> > circuitry and found nothing.......I placed my finger on the
> > F84 and it was
> > very HOT.  I said to myself...hey what's going on
> > here........the battery
> > pack was backwards (alligator clips).
> >
> > Bottom line.....what you say has merit.  I never did put in
> > any reverse
> > polarity protection.  The project is supose to run until the
> > batteries are
> > depleted and it is a low cost device.  I could not afford a
> > voltage drop.
> >
> > 3 volts would probably have minimal effect, except killing
> > the batteries :)
> >
> > David
> >
> >
> > ----- Original Message -----
> > From: Tony Nixon <Tony.Nixon@ENG.MONASH.EDU.AU>
> > To: <PICLIST@MITVMA.MIT.EDU>
> > Sent: Monday, May 31, 1999 6:31 PM
> > Subject: Re: Reverse Polarity Protection for 3V PIC Circuit.
> >
> >
> > > Peter Homann wrote:
> > > >
> > > > Hi,
> > > >
> > > > I need to protect my PIC16LF84 against reverse polarity.
> > Currently I'm
> > > > running the circuit of 2 x 1.5 N cells (2/3 AAA). I want
> > to protect the
> > > > circuitry from the batteries being inserted the wrong way.
> > >
> > > Just a thought,
> > >
> > > I wonder if the PIC will be damaged at all with a 3V
> > reversed battery.
> > >
> > > Every protection diode on the IO pins will be conducting
> > between VCC and
> > > GND rails in the chip, thus trying to drop the battery
> > voltage to around
> > > 1.2V.
> > >
> > > Maybe no damaging current is available to flow into the
> > chips' 'guts'.
> > >
> > > Perhaps a simple resistor in series with VCC will suffice
> > to limit this
> > > current.
> > >
> > > Maybe this is why I have not damaged 16F84's by inserting
> > them into a
> > > socket the wrong way around.
> > >
> > > --
> > > Best regards
> > >
> > > Tony
> > >
> > > PicNPoke - Multimedia 16F84 Beginners PIC Tools.
> > >
> > > http://www.picnpoke.com
> > > Email picnpoke@cdi.com.au
> > >
> >
>