Transient thermal impedance from the junction to the case Z,JC is used to
determine the change in junction temperature due to momentary changes in
absorbed power. Manufacturers typically supply transient thermal impedance
information on datasheets. Figure 10-24 shows a graphical representation of Z,JC
as well as the RC equivalent circuit representation for the junction to case for the
IRF4104 MOSFET. Transient thermal impedance is also denoted as Zth.