Stroomshunts

Stroomshunts, or current shunts, are low-resistance components used to measure electrical current by producing a small, proportional voltage drop. The voltage across the shunt is proportional to the current flowing through it, following Ohm's law (V = I × R).

They are placed in series with the load and the resulting voltage is read by a voltmeter or an instrumentation amplifier. There are low-side shunts (between the load and ground) and high-side shunts (between the power source and the load); high-side shunts allow measurement with larger common-mode voltages but require differential or isolated measurement.

Construction and ratings: Shunts are designed for very low resistance values, typically from a few micro-ohms to a few milliohms, and are rated for high currents. Materials include manganin, constantan, or copper alloys, in forms such as metal bars, PCB traces, or packaged resistors. Power rating P = I^2 × R determines heating and thermal drift. Shunts may be specified for certain isolation voltages and packaging, and some designs include features for temperature compensation.

Accuracy and calibration: Tolerances, temperature coefficients, self-heating, and contact resistances affect measurements. Shunt voltage is sensitive to temperature; many devices specify a temperature coefficient in ppm/°C. Proper mounting, cooling, and, when needed, calibration against a traceable standard improve reliability.

Applications: Used in power supplies, battery management systems, renewable energy installations, motor drives, automotive electronics, and test benches for current measurement in DC and, with suitable designs, pulsed or high-current systems.

Safety and considerations: ensure the shunt is rated for maximum current and voltage, meet isolation requirements if needed, and calibrate against traceable standards. Consider transient response and any parasitic inductance in high-frequency or pulsed applications.

See also:

- Current sensor

- Shunt resistor

- Hall effect sensor

- Ohm's law