Function and working principle of shunt

1. The role of the shunt

To measure a large DC current, such as tens of amperes, or even larger, hundreds of amperes, what should I do if there is no ammeter with such a large range to measure the current? This requires the use of a shunt.

It is a short conductor, which can be made of various metals or alloys, and its DC resistance is strictly adjusted; when connected in series in a DC circuit, the DC current flows through the shunt, and the two ends of the shunt generate a millivolt-level DC voltage signal. Swing the pointer of the meter connected at both ends of the shunt, and the reading is the current value in the circuit.

The so-called shunt is to divide a small current to push the meter indication. The smaller the ratio of this small current (mA) to the current in the large loop (1A-tens of A), the better and more accurate the line indicating the reading of the ammeter. This is a common product for electrical circuits, and there are shunt measures for lightning protection.

2. Working principle

The shunt is used to measure DC current, and it is made according to the principle that when DC current passes through the resistor, a voltage is generated across the resistor. The shunt is actually a resistor with a small resistance value. When a DC current passes through, a voltage drop is generated, which is displayed by a DC ammeter.

The shunt is actually a resistor that can pass a very large current. Generally, the commonly used 15A, 20A and 35A ammeters require a shunt. The impedance of the shunt is calculated by "the full-scale voltage of the meter head/the full-scale current of the meter head". .

The so-called shunt is to divide a small current to drive the meter indication. The smaller the ratio of the small current to the current in the large loop, the better the linearity and accuracy of the ammeter reading.