Shunt

ShuntA shunt is a device that allows electric current to flow, bypassing any section of the circuit. It is usually a low ohm resistor. For example, shunts are used to change the upper measurement limit of ammeters of the magneto-electric system. The required shunt resistance is calculated by the formula: Where R2 is shunt resistance;• R1 is the resistance of the ammeter;• I is the maximum current that will correspond to the full deflection of the needle of the device;• I 1 is the rated maximum current, measured by the ammeter without the shunt.If the desired change limit far exceeds the rated current of the ammeter, then this current in the denominator can be neglected, and the formula will look like that: For example, to measure currents up to 10 A using an ammeter with 2000 ohms resistance and a maximum current of 50 microamps, you will need a shunt with 0.01 ohms resistance.The use of shunts allows you to expand the limits of the ammeter readings (at the expense of worsening the resolving power and sensitivity of the instrument).Depending on the shunt resistance, a copper wire on the coil, a metal plate, a normalized (standard) resistor with a low tolerance of resistance deviation can be used as this element.

Category:

Science & Technology

Tags:

• circuitry
• measurement
• resistor