# AC Thevenin's Theorem

Any combination of sinusoidal AC sources and impedances with two terminals can be replaced by a single voltage source e and a single series impedance z. The value of e is the open circuit voltage at the terminals, and the value of z is e divided by the current with the terminals short circuited. In this case, that impedance evaluation involves a series-parallel combination.

 Thevenin voltage Thevenin resistance Numerical example Norton equivalent
 to DC Version
Index

AC circuit concepts

 HyperPhysics***** Electricity and Magnetism R Nave
Go Back

# AC Thevenin Example

To replace a network by its Thevenin equivalent, compute the Thevenin voltage: the output of the voltage divider formed by Z1 and Z3 . The Thevenin impedance is the impedance looking back from AB with V1 replaced by a short circuit and is therefore a a series-parallel combination.

 For impedances
 Z1 = + j
 Z2 = + j
 Z3 = + j
 with supply voltage
 V1 = V,

 the Thevenin voltage would be
 VTh = e = + j V
 VTh = e =V at degrees.
 The Thevenin impedance is
 ZTh = + j
 ZTh = ohms at degrees.
 Thevenin resistance Thevenin voltage DC example Norton equivalent
Index

AC circuit concepts

 HyperPhysics***** Electricity and Magnetism R Nave
Go Back