A study of the temperature coefficient of constriction resistance

Abstract

The constriction resistance Rm is related to the maximum temperature Tm, the constriction resistance Re at reference temperature Te, and the temperature coefficient α by the relation Rm = Re[1 + (2/3)α(Tm - Te)]. The constant 2/3 here is derived approximately on the assumption that the equipotential surface and equal temperature surface coincide within the contact. If heat is transferred into the external atmosphere through the apparent contact surfaces and/or the contact faces, the constant 2/3 may not be valid because of the disagreement between the two distributions. The effect of heat transfer on the constant is numerically clarified by using the finite difference method. The numerical studies indicate that the constant is dependent on the value of a pure number, that is, (half width of real contact surface) × (heat transfer coefficient)/(thermal conductivity). If this value is less than or equal to 10−3 to 10−2, the relation Rm presented earlier holds, and then the constant 2/3 has an error of about 4.7%. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 2, 80(4): 35–43, 1997