Hi Dave,

I think Anand knew that. He was simply saying that it _appeared_ to be
a violation if you forgot that volt meters are not perfect.

Sean


On 4/2/07, David Minkler <mink@luxtron.com> wrote:
> Kirchoff's Voltage law doesn't apply to a circuit under different
> operating conditions, it is a statement about instantaneous conditions.
> It merely states that the sum of voltages around a given circuit add to
> zero.  The very nature of the universe insures that this is always so.
> It's the closed path that does the trick, not some feature of the 'trons.
>
> Dave
>
> Anand Gadiyar wrote:
>
> >Sean and Paul,
> >
> >   Right on. :)
> >
> >Regards,
> >Anand
> >
> >On 4/2/07, PAUL James <James.Paul@colibrys.com> wrote:
> >
> >
> >>All,
> >>
> >>And if this is the correct diagnosis, you should be able to use two
> >>voltmeters, one between the pin and ground,
> >>And the other between the pin and VCC and read voltages on both.
> >>
> >>
> >>Regards,
> >>
> >>
> >>Jim
> >>
> >>
> >>
> >>-----Original Message-----
> >>From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
> >>Of Sean Breheny
> >>Sent: Monday, April 02, 2007 1:08 PM
> >>To: Microcontroller discussion list - Public.
> >>Subject: Re: [EE]: Kirchhoff's Voltage Law - violation?
> >>
> >>Hi Anand,
> >>
> >>My guess would be that the output was actually acting as a very weak
> >>pull-up (perhaps it was set to be open-drain and we are looking at diode
> >>leakage) so that when the meter is put between the pin and Vcc, there is
> >>no current flow at all through the meter, so it reads 0 volts. When the
> >>meter is placed between the pin and ground, the input impedance of the
> >>meter draws enough current to cause a 1 V drop across whatever is
> >>pulling the pin high.
> >>
> >>Sean
> >>
> >>
> >>On 4/2/07, Anand Gadiyar <gadiyar@ieee.org> wrote:
> >>
> >>
> >>>Hi all,
> >>>
> >>>    I noticed something interesting while playing around with a
> >>>GAL16V8 device. I finally figured it out, but it's an interesting
> >>>puzzle and I thought it worth sharing.
> >>>
> >>>   Using a voltmeter, the Vcc pin shows 5 volts with respect to GND.
> >>>And a output pin at logic high shows 4 volts with respect to GND. The
> >>>same pin shows 0 volts with respect to the Vcc pin. The same is
> >>>observed when i used a CRO to look at the waveforms.
> >>>
> >>>   Also tried this on a PALCE22V10 device and it behaves similarly.
> >>>
> >>>   See if you can figure it out. I'm pretty sure you guys will throw
> >>>more light on the puzzle, else answers in two days.
> >>>
> >>>Warm regards,
> >>>Anand
> >>>
> >>>__________________________
> >>>Anand Gadiyar
> >>>Indian Institute of Science,
> >>>Bangalore - 560 012
> >>>__________________________
> >>>--
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