# Maximum Power Transfer Theorem **A theorem that states when a two-terminal linear circuit delivers maximum power to a load.** > [!NOTE] Maximum Power Transfer Theorem > The *maximum power transfer theorem* states that a two-terminal linear circuit delivers the maximum [[Complex Power#Average Power|average power]] to a load when its impedance is equal to the [[Thevenin's and Norton's Theorem#Thevenin impedance|Thevenin impedance]] as seen from the load. That is, > $\mathbf{Z}_{\text{L}}=\mathbf{Z}^{*}_{\text{Th}}$ > The value of this average power is > $P_{\text{max}}=\frac{\vert\mathbf{V}_{\text{Th}}\vert^{2}}{8R_\text{Th}}$ > If the load is *purely resistive*, then the maximum average power transfer occurs when > $R_{\text{L}}=\vert\mathbf{Z}_\text{Th}\vert$ > The value of the power transferred is calculated as [[Complex Power#^d8d1b7|normal]].