Question

For ZL  = ZS*, the relation between XL and XS is?

(a) XL = XS

(b) XL = 0

(c) XL = 1

(d) XL = -XS

This question was posed to me in class test.

The doubt is from Maximum Power Transfer Theorem topic in portion Useful Theorems in Circuit Analysis of Network Theory

Answer 1

Correct choice is (d) XL = -XS

Easiest explanation: For ZL = ZS*, the relation between XL and XS is XL = -XS. Maximum power transfer is not always desirable since the transfer occurs at a 50 percent efficiency.