acceptable voltage drop 1v?

Thread Starter

hamed_HT

Joined Sep 3, 2017
1
Hello everyone,
To get power measurement I have to need to locate a resistor on the power line and measure the voltage across with an oscilloscope. The challenge is that the how much resistance shunt for power line 1V. Acceptable voltage drop for power line 1V?
help me.
 

DickCappels

Joined Aug 21, 2008
10,169
It depends on what the measurement is for. Assuming this is not test for conformance to some recognized standard a 1 volt drop will be low compared to the 120 or 220 volt line voltage and in many cases can reasonably be ignored.
 

crutschow

Joined Mar 14, 2008
34,414
.........The challenge is that the how much resistance shunt for power line 1V...........
That's not the challenge.
The challenge is to do that without electrocuting yourself or zapping the oscilloscope on an unisolated mains line. :eek:
That's a measurement that should never be done unless you have a isolation transformer for the AC load.

If you are very careful you can do it by connecting a multimeter set as an AC ammeter in series with the line.
 
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