Thevenin and Norton Equivalence

The open circuit, short circuit and load conditions of the ThZ¯venin model are:Voc = EIsc = E / ZVload = E - IloadZIload = E / (Z + Zload)
The open circuit, short circuit and load conditions of the Norton model are:Voc = I / YIsc = IVload = I / (Y + Yload)Iload = I - VloadY
Thevenin model from Norton model
Voltage = Current / AdmittanceImpedance = 1 / Admittance
E = I / YZ = Y -1
Norton model from Thevenin model
Current = Voltage / ImpedanceAdmittance = 1 / Impedance
I = E / ZY = Z -1
When performing network reduction for a Thevenin or Norton model, note that:- nodes with zero voltage difference may be short-circuited with no effect on the network current distribution,- branches carrying zero current may be open-circuited with no effect on the network voltage distribution.