Contact resistance calculator — temperature rise

The contact dissipates P = I² × R (R in Ω), and the steady-state rise is ΔT = P × Rth, where Rth is the thermal resistance from the contact to ambient. With the defaults — 5 mΩ, 10 A and Rth 60 °C/W — the loss is 0.5 W and the rise is 30 °C.

At 10 A a 5 mΩ mated pair dissipates 0.5 W (P = I²R) and drops 50 mV across the contact. The calculator flags a rise above 30 °C as high — for a signal contact that usually points to a degraded or oxidized interface, not the raw material.

Gold-plated signal contacts typically hold 2–5 mΩ per mated pair, and anything under 10 mΩ is the usual low-signal target. The calculator uses 5 mΩ as its default because it is typical for a small gold-plated signal contact at 10 A.