Re: [CAD_CAM_EDM_DRO] panel meters

Thank god I caught myself. I almost said "You can't route 200 amps
through the meter body
because the impedance is so high. And, BTW, it was 20 amps." Then
someone would
have said "In what galaxy???" Then I would have had to say "What?"
Then whomever
said "In what galaxy???" wouldn't reply, and I would have had to figure
out "Oh yeah,
you CAN route 200 amps through a meter with, say, 100 000 000 ohms
input impedance,
you just need a 20 000 000 000 volt power supply" Then I would have
realized that the
whole exchange was a waste of time, since it didn't help anyone with a
problem. Then
I would have realized that the person asking "In what galaxy???"
didn't contribute
anything to the person's original problem. Then I would have realized
that the person
asking "In what galaxy???" spent about 2 seconds reading part of the
original message
and replying to the original message, as opposed to my spending a good
10 minutes on it,
researching a part number, checking wording, spelling, readability,
math, etc. Then I would
have posted a message like this, all the while remembering the old
adage, "Even if you win
a p---ing contest. You still get p---ed on." Then I would have said,
"Screw this, I'm going to the shop."

Thank god I caught myself.

Regards,
JJ

On Tuesday, Mar 9, 2004, at 23:32 US/Eastern, Harvey White wrote:

> On Tue, 9 Mar 2004 14:27:45 EST, you wrote:
>
>> In a message dated 3/9/2004 11:12:15 AM Central Standard Time,
>> johnatl@... writes:
>> Connect the meter
>> across the 1 000 ohm resistor. The voltage displayed will be 1/1000
>> the
>> input, i.e. 200V in will put 200mV across the meter.
>>
>> As far as current, you'll need a very low resistance, precision
>> resistor to put in series with your power supply and load. Scaling is
>> similar to above. E.g. You have a 0-200mV meter, and you want to
>> monitor 0-20A. So, we know we want 200mV out for 20A current, so:
>> .200
>> In what galaxy???
>
> You buy a shunt, rated for that current, and that voltage drop. May
> or may not be readily available, but they do exist. It's common
> practice in higher current meters to have an external shunt, rather
> than route 200 amps through the meter body.
>
> Harvey
>
>
>
>
>
>
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