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Calibrated Resistor / Shunt for Direct Current (DC) Measurements

Photo of a calibrated resistor shows two metallic squares with bolts on the top connected by metal.

Calibrated resistor

A calibrated resistor (also called a shunt) can be used to measure direct current (DC) with high precision. The current of interest is passed through a resistor of known resistance, R, and the voltage drop V is measured across the resistor. Per Ohm's Law, I=V/R. These types of measurements may be required when investigating the energy use characteristics of a DC component within a system. For example, you could use a shunt to measure how much power the fan is drawing inside of a furnace.