Laboratory measurements on a dc voltage source yield a terminal voltage of 75 V with no lo...

Laboratory measurements on a dc voltage source yield a terminal voltage of 75 V with no load connected to the source and 60 V when loaded with a 20 Ω resistor.

a) What is the Thévenin equivalent with respect to the terminals of the dc voltage source?

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b) Show that theThévenin resistance of the source is given by the expression

where

υTh = the Thévenin voltage,

υo = the terminal voltage corresponding to the load resistance RL.