"Roger" wrote in message
...
On Fri, 17 Feb 2006 10:07:50 -0800, "RST Engineering"
wrote:

Yeah, I'll give you that I missed the "powered from the measured voltage"
part. It becomes a bit less trivial. Practically impossible.

As for sticking pins through the wire a foot apart, you are going to get
more contact resistance (and corrosion as time goes on) than the shunt
itself. If you are using the primary wire as the shunt, I'd break the
wire,
use a terminal strip with a shorter piece of thinner wire a few inches
long,
then back to the larger wire.

I'm wondering if the OP may have mis worded, or mis understood.

As you say the measurement is trivial, however I'm wondering if he
didn't think of powering the meter from the same source as was
*providing* the current rather than the current being measured. That
would make sense. Then it'd be easy and as you said, practically
impossible if powered from the *measured* current.

What am I missing here? A good old fashioned analog ammeter is powered from
the "measured current".
Or, you can use a Simpson panel meter with your shunt. No power required. Of
course, they cost a fair bit of change nowadays.

http://www.simpsonelectric.com/pdf/w...-Vue%20ADC.pdf

You only need "power" if you want some kind of fancy pants digital readout.

--
Geoff
The Sea Hawk at Wow Way d0t Com
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