# Is it accurate way to use Shunt Resistor measuring less than 10mA current

#### vishnuatacc

Joined Dec 26, 2017
4
Hello all,
I want to measure how much current consume for a coin cell battery operated wireless sensor network, the expected range of current is below 10mA. Is it accurate to use the shunt resistor method for this type of measurement? or any best methods are available. If the shunt resistor method is a good way, how can I decide the resistor value, such that I can get accurate results?

Thank you
D.Vishnu

#### ericgibbs

Joined Jan 29, 2010
14,670
hi vis.
Do you have sensitive voltmeter capable of measuring millivolts.?
E

#### vishnuatacc

Joined Dec 26, 2017
4
hi vis.
Do you have sensitive voltmeter capable of measuring millivolts.?
E
Hello ericgibbs,
Yes we are having voltmeter that capble of mesuring in mV.
We are thinking we will use oscilloscope to probe across resistor for measuring voltage.

#### ericgibbs

Joined Jan 29, 2010
14,670
hi,
If you used a1R shunt resistor in series with the high side of the battery output, a 10mA current will read 10mV across the 1R.
E
10mA = V/R = 0.01/1

#### ScottWang

Joined Aug 23, 2012
7,117
Using 0.1Ω shunt resistor then V= I*R = 10mA * 0.1Ω = 0.001V = 1mV
What range of the shunt resistor that you should use, that is depends on the accurate voltage that you want as 1mV or 10mV.