Superposition: $$ \text{ Deactivate the voltage source} \rightarrow \text{short circuit} $$ $$ \text{ Deactivate the current source} \rightarrow \text{open circuit} $$
Thévenin’s Theorem: $$ R_{Th} \text{ all source to zero, } E_{Th} \text{ open-circuit terminal voltage} $$
Norton’s Theorem: $$ R_N \text{ all source to zero, } I_N \text{ short-circuit terminal current} $$
Maximum Power Transfer Theorem: $$ Z_L = Z_{Th}^* = Z_N^* \text{ , } P_{max} = \frac{E_{Th}^2}{4R_{Th}} = \frac{I_N^2R_N}{4} $$