shunt resistor
Shunt means to connect in parallel in German, a shunt resistor is therefore also called a shunt resistor. It is a low-resistance resistor that is connected in parallel to a measuring element and whose voltage drop is used for measurements of high current. Since higher currents cannot be measured directly, they are passed through a shunt resistor and the resulting voltage drop is measured. Accordingly, the resistance value of shunt resistors is in the milli-ohm range and below, at a few tenths or hundredths of a milli-ohm.
Inmeasurement technology, shunt resistors are used for the various current measurement ranges of measuring instruments. The shunt resistor conducts the current to be measured past the measuring element and generates a voltage drop in the shunt resistor that can be measured by the measuring elements. Separate shunt resistors are available for larger currents ranging from a few amperes (A) to several hundred or thousand amperes. Shunt resistors are equally suitable for direct and alternating current. To ensure that the resistance value of shunt resistors does not change due to the current flowing through them and the associated heat generation, shunt resistors are made of materials with neutral temperature coefficients.
Important characteristic values of shunt resistors are the nominal load, the nominal current, the voltage drop at the shunt resistor and the accuracy.
A shunt resistor is calculated according to Ohm's law, using the difference between the total current and the current flowing through the meter. In the formula, the value for the shunt resistance is the quotient between the meter current and the differential current multiplied by the internal resistance of the meter.