Work out shunt resistor instantly with clear inputs, formula shown and shareable results.
A current shunt is a precise low-value resistor: R = full-scale voltage divided by full-scale current, so a 50 A / 75 mV shunt is 1.5 milliohms. Dissipation at full scale is I squared R, which is why high-current shunts need substantial physical size and often forced cooling.
Shunt resistor
R = Vfs / Ifs; P = I^2 x R; measured voltage = I x R
Electrical results are planning estimates only. Verify against the applicable wiring rules (IEC 60364, BS 7671, NEC or local code) and have all installation work designed and checked by a qualified electrician.
Panel meters and analogue instruments were standardised on 50, 75 or 100 mV full scale, so shunts are still made to match. It is a compromise between signal size and dissipation.
Separate sense terminals keep the lead and contact resistance out of the measurement, which matters enormously when the shunt itself is only a milliohm.