Partial model of a resistance that links two generalized electrical connectors.
The model computes a resistance R(T) that varies depending on the temperature T as
R(T) = Rref (M + T)/(M + Tref),
where the resistance Rref is the reference
value of the resistance, M is the temperature coefficient of
the cable material, and Tref is the reference
temperature. The temperature T is the temperature of the
heat port if useHeatPort = true.