Calculate the shunt resistor R_N for a desired calibration signal (exact and per the approximation eq. 8.7) and the strain it simulates.
Enter values and run the calculation.
A high-value resistor across one arm lowers its resistance and unbalances the balanced bridge reproducibly – the whole measuring chain can be checked without mechanical load. Keil's example: 0.5 mV/V on a 120 Ω bridge needs a 60 kΩ shunt per eq. 8.7; exactly 59.94 kΩ.
R_K = R_N·R/(R_N+R) (Keil Gl. 8.1)
U_M = ½U_B·R/(2R_N+R) (Keil Gl. 8.5)
U_M/U_B ≈ R/(4R_N) ⇒ R_N = U_B·R/(4U_M) (Keil Gl. 8.6, 8.7)
ε_sim = −4·(U_M/U_B)/k
Placing the shunt across the whole half bridge instead of one arm, or interpreting the negative sign of the simulated signal as a fault.
Checking and reproducing the calibration of force transducers and load cells in situ, function checks of remote measuring points, scaling of data-acquisition systems.
Applies to the balanced bridge with constant excitation; lead resistance between shunt and arm alters the signal slightly at DC and considerably at high carrier frequency.
Keil, Dehnungsmessstreifen, 2nd ed. 2017, sec. 8.7.3 shunt calibration, eqs. (8.1)–(8.7), fig. 8.7.
The source supports the equation structure and worked examples; this calculator does not replace calibration of the measuring chain.
No, it only reproduces an electrical signal; the signal ↔ quantity relation must be established once with a reference standard.
The parallel resistor reduces the arm resistance like a compression of the gauge.
At least the target calibration accuracy, typically 0.01 to 0.1 %, with a low temperature coefficient.