Objective:  Verification of Maximum power transfer theorem.

Maximum power is transferred from a source of given voltage and an internal impedence to the load impedence Z_L in a circuit (Fig.-1) under three conditions.

                                                    (A) When only X_L is adjustable:

Under this condition the power consumed by the load (I²*R_L) is maximum, when I is maximum, since R_L is constant.

 This means that if the load reactance(X_L)  is made equal magnitude and opposite in sign to the internal reactance(X_i), the power transferred is maximum.

                                             (B) When only R_L is adjustable:

From equation (1) in section (a), one may write,

Differentiating the equation ( 3 ) w.r.t  R_L and equating to zero, one obtains.  

                                         (C) When both R_L and X_L are adjustable:

Under this condition both equation (2) are valid simultaneously and one obtains.

                                                                                                             Fig.-1.