mynick wrote:
want to shunt a multimeter to extend it's ac ampermeter range so
measured with Rish 14s in ohm meter position about 41 ohms
and then measured with Rish 14s its own internal resistance to get 40
ohms
Is this way to much -there is some mistake?
(http://www.multimetercalibrationsaus...shmulti14s.pdf
but cannot find data about it's internal resistance!)
Now that i told you how to determine (NOT directly measure) the
resistance of a meter, FORGET that happy horsemanure.
Use that low voltage adjustable supply and resistor in series;adjust
to get full scale reading.
Now...hold your breath...measure the VOLTAGE across the meter.
THAT is what you want your meter shunt to drop, for full scale reading.
So it does not matter if the meter was 5uA, 100uA or 1mA; treat it as
if it was a voltmeter, measuring the voltage drop across the ten amp
shunt (or whatever you wanted).
So, you asked the wrong question (internal resistance).