What is a shunt?

 The shunt is used to measure DC current;

   The shunt is actually a resistor with a small resistance value. When there is current passing through, a voltage drop will be generated, which is displayed by the DC ammeter;

   The DC ammeter is actually a voltmeter with a full scale value of 75mV;

   DC ammeter and shunt are used together;

   For example: the resistance value of the shunt matched with the 100A ammeter is 0.00075 ohms;

   That is, 100A*0.00075Ω=75mV;

   The resistance value of the shunt matched with the 50A ammeter is 0.0015 ohm;

   50A*0.0015Ω=75mV.