The determination of equivalent constriction resistance and film resistance by using low DC voltages

The change in a contact resistance due to the applied voltage is expressed by a formula, which indicates that this change is approximately proportional to the ratio of the constriction resistance to the film resistance in a series circuit model. It is possible to determine the equivalent values for the both these resistances by making use of the theory being presented and experimental data on the change in contact resistance. Experiments were conducted to measure the change in the contact resistances for cross wire contacts of Ag-Ag and Cu-Cu with a load of 0.1 to 1 N, when the contact voltage was decreased from ∼15 mV to ∼10 mV. It was found that the equivalent film resistance was about 70% of the total for high resistances (>1 Ω) and only 10 to 40% for low values (<0.01 Ω).