On Wednesday, June 1, 2016 at 6:57:42 AM UTC-4, FromTheRafters wrote:

It's not a circuit unless there is continuity "open circuit" is a
misnomer. When you put the multimeter across the open (gap) the
internal resistance of the meter completes the circuit and you read the
'voltage drop' across that internal resistance which tells you what the
supply voltage is, because as you said, they must be equal.

No completion of that circuit is necessary to measure the voltage
potential.

I didn't say that there was. What I said was that the meter completed
the circuit and the measurement was taken from the 'voltage drop'
across the internal resistance of the meter.

Which implies that completion of the circuit is necessary to be able
to measure the voltage source, hence my reply. If you're not implying
that, what's the point of bringing it up at all? More FUD like bringing
up calculus when you can't do simple math?




The meter has an impedance in the meg ohms and for all
practical purposes can be ignored for the purposes of this discussion.

Maybe for your discussion, but not for mine.

See, I was right, you do want to go off into more nits, when the real
problem here is that you think V = IR, with I=0 somehow involves
division. And that you can't recognize that when an equation like
that gives a value of zero, the zero has meaning. Often in science
and engineering the zero results are among the most interesting,
that solve the problem, etc.


Voltage can exist without
current and current can exist without voltage, but 'voltage drop'
requires current and resistance and Ohm's Law works under those
conditions no matter how close to zero they get without actually being
zero.


And Ohm's Law works at zero too. I've asked 6 times now, have you
drawn a graph of Ohm's Law, plotted, I vs V? You get a straight line,
it goes right through the origin.


And there are non-contact measuring techniques and instruments as well.
You can measure electric potential without a circuit.

I agree with that statement. But you can't measure 'voltage drop'
without current going through the device which is responsible for it.


That's like saying you can't measure the speed of your car, without
the car moving. The rest of us recognize that as a speed of ZERO.

Assignment for a grade school student. Keep a tabulation of the
speed of a car while dad is driving,
record the observations every minute. What speed entry do you
make when the time for an observation occurs when the car is stopped
at a light? The rest of us would put in zero. You? Apparently you'd
argue that the speed is "undefined" because to make that entry would
require division by zero.

Next assignment, calculate the average speed using those recorded
measurements. We'd take all the tabulated entries, add them up and
divide by the number of entries. Let's say there were ten. We have

35, 42, 47, 0, 40, 50, 30, 0

We get (35+42+47+0+40+50+30+0)/8 as the answer

WTF do you get? Speed is undefined because the car is not moving, right?

(35+ 42+47+undefined+40+50+30+undefined)/8 So, answer is undefined?

(35+42+47+40+50+30)/6 ?

That's the screwy world you're living in.



You really
are in way over your head here.

Sure, if you say so. But I don't stick to the shallow end of the pool
like you do. You should stop trying to put words in my mouth so I won't
feel as if I should respond, it makes you look like a troll.

If anyone is a troll, it's you. It's been a long time since we've
seen a total moron here like you. BTW, we're all still waiting
for you to explain how 1 squared can be 2 sometimes, another one
of your claims.