Precision 100 Amp Current Shunt , 50 Amp Dc Ammeter 50mV 60mV

DC Current Shunts, Russian Type, 5A-3000A, 50mV, 60mV, 75mV, 100mV

DC Current Shunts are low resistance precision resistors used to measure AC or DC electrical currents by the voltage drop those currents create across the resistance.
Power Rating : Watts (W) = Current (I2) x Resistance Value (R)
The heat produced is power measured in Watts (W).
Current shunts dissipate heat from the current flowing through them, when they get hot.
In practice current shunt is often rated to be used continuously at only 2/3 of their "rated current".
Since that heat can change their resistance and even permanently damage the shunt, so it is often given a power rating or a derating factor.
Calculate Current : Current (I) = Voltage (V) / Resistance Value (R)
By inserting a current shunt into a circuit to get the current you want to measure while the voltage dropped across the shunt.
Then knowing the resistance of the current shunt you can calculate the current by using Ohm's law.