Shunt principle

Update:28-09-2018
Summary:

A shunt is actually a resistance with very small resist […]

A shunt is actually a resistance with very small resistance. When a direct current passes through it, a voltage drop is generated for the display of a direct current ammeter.
The DC ammeter is actually a voltmeter with a full scale of 75mV.
DC ammeter and shunt are used together.
For example, the current resistance of 100A ammeter is 0.00075 euro.
Namely, 100A*0.00075 Europe =75mV;
The shunt resistance of 50A ammeter is 0.0015 euro.
50A*0.0015 Europe =75mV.