How do you calculated the current shunt?

Write down the Ohm's law expression of "V = I * R" where "V" is the voltage drop across shunt resistor, "I" is the current flowing through shunt and "R" is the shunt resistance.

Substitute value of voltage "V" and current "I" in the Ohm's law expression. For example, if voltage across shunt is 10 volts and current flowing through it is 1 ampere, then the expression is 10 = 100 * R.

Divide the expression throughout by 100 to calculate the "R" value. Using a calculator, find the value of "R." From the example, the value of "R" will be 0.1 ohm, which is the value of shunt resistor.