(II) Assume a voltage source supplies an ac voltage

Chapter , Problem 51

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(II) Assume a voltage source supplies an ac voltage ofamplitude V0 between its output terminals. I f the outputterminals are connected to an external circuit, and an accurrent of amplitude / 0 flows out of the terminals, then theequivalent resistance of the external circuit is Req = Vq/ I 0.(a) I f a resistor R is connected directly to the outputterminals, what is R eq? (b) I f a transformer with Np and N$turns in its primary and secondary, respectively, is placedbetween the source and the resistor as shown in Fig. 29-46,what is Req? [Transformers can be used in ac circuits to alterthe apparent resistance of circuit elements, such as loudspeakers, in order to maximize transfer of power.]