On 02/01/2013 12:11, newshound wrote:
On 02/01/2013 12:09, newshound wrote:
On 01/01/2013 20:19, wrote:
As part of another project, would like to take some High Current DC
measurements.

I have a couple of multimeters ... but obviously not going to be any
good for around 80-100A

Now going back to school physics lessons I could use a Shunt resistor
...
http://www.societyofrobots.com/robot...?topic=13900.0

The issue will be obtaining a suitable shunt ... assuming I use a 1
ohm shunt, anybody made one of these ?
The WEB ref
page:http://www3.zetatalk.com/docs/Electr...Meter_2007.pdf


details using 12guage copper wire .. based on 1.619 ohm per 1000'

Although maybe a resistance wire may be better eg Nichrome around
10.58" for 1 ohm.
Welcome to any better ideas.


Other posters have covered shunt design and issues in plenty of detail.

Pico Technology used to do a "clamp" type ammeter which you connect to a
normal DVM, and which does DC as well as AC amps, but it looks as though
this has been discontinued. ISTR it was about £50. Occasionally very
handy for car diagnostics (I think it gives 1 mV per amp).


Oh yes, here it is

http://www.picoauto.com/current-clamp.html

(Web site search facility is crap!)



Now one of those would be good ... but not at that price :-)