Norton & Thevenin theorem

Thé venin's Theorem

Any voltage network which may be
viewed from two terminals can be
replaced by a voltage-source
equivalent circuit comprising a single
voltage source E and a single series
resistance R.. The voltage V is the
open-circuit voltage between the two
terminals and the resistance Z is the
resistance of the network viewed from
the terminals with all voltage sources
removed from circuit.

Sample

All circuits are equivalent. Resistors
R₁,R₂, R₃ and voltage source are
transformed into Required Eq,

see parallel,
series simplifications.

To determine Eequ we shall break off
branch connecting node 1 and node
2

Norton's Theorem

Any current network which may be
viewed from two terminals can be
replaced by a current-source
equivalent circuit comprising a single
current source I and a single shunt
conductance G. The current I is the
short-circuit current between the two
terminals and the conductance G is
the conductance of the network
viewed from the terminals with all
branches containing current sources
are broken off.