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5
Thermal Resistance
Network
5.1 THERMAL RESISTANCE CONCEPT
Consider an electrical resistor shown in Figure 5.1. If there is a potential difference
between the two ends of this resistor, a current will ow through it. The direction of
this current is from the high potential to the low potential ends of this resistor, and
its magnitude is given by the Ohm’s law;
(5.1)
Now, consider a layer with thickness L and surface area A as shown in Figure 5.2.
If there is a temperature difference across this layer (i.e.,
there will be
conduction heat transfer from its high temperature side to its low temperature side.
Fourier’s law t