Linear Circuit Analysis


Maximum Power Transfer in DC circuits

Maximum power transfer

Consider the circuit in Fig. 1. If $V_{Th}$ and $R_{Th}$ are specified and one can change the value of the load resistance, the maxium power transfer occurs when $$\begin{equation}R_L=R_{Th}\end{equation}$$

VTh RTh + VL IL RL
Fig. 1. Maximum power dissipated by the load occurs when $R_L=R_{Th}$.

In general, if the $V_{Th} - R_{Th}$ series connection is replaced by a 2-port linear network containing multiple resistors, voltage sources and current sources, the 2-port network can always be replaced by its Thévenin equivalent circuit and we can use the above equation to calculate the load resistance for which the power transferred is maximum.

Sample Solved Problems
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