How rtd bridge works
R4 is the platinum RTD. Its resistance at 0 °C sets the three matched reference arms R1–R3. The output is the RTD midpoint minus the reference midpoint. R1 supplies the nominal 0 °C resistance; changing R4’s temperature updates its calculated resistance in the schematic and guest circuit.
IEC platinum coefficients A = 3.9083 × 10⁻³ °C⁻¹ and B = −5.775 × 10⁻⁷ °C⁻², valid here from 0 to 200 °C. Ideal matched bridge arms, no lead resistance, tolerance or self-heating correction.
Change the form inputs or click a component value on the schematic. Choose Try in CircuitSim to simulate the configured circuit.