Electrical Circuit Network Theorems Definitions and Key Facts

Definition Terms of a Network Theorems and key facts

Active  network 
A Network containing one or more sources of electro motive force ( e.m.f) is known as an active network.

Branch 
A single path containing one simple element  which connects one node to any other node is know as branch.

Bilateral Circuit 
A circuit having identical properties in either direction is know as bilateral circuit. Transmission line is bilateral.

Circuit 
A circuit is a conducting part through which either an electric current flows or is intended to flow.

Linear Circuit 
A linear circuit is one whose parameters are constant.. do not change with voltage or current.

Non-Linear Circuit 
It is that circuit whose parameters change with voltage or current.

Node
A point at which two or more elements have a common connection is called a node.

Parameters
The various elements of an electric circuit are called its parameters like resistance, inductance and capacitance. These may be lumped or distributed.

Unilateral Circuit
It is that circuit whose properties changes with the direction of its operation. A vaccume tube rectifier is a unilateral circuit.

Key facts on Network Theorems

• Kirchhoff's law is applicable to ac ( alternation current) as well as DC ( direct current)  circuits.
• An ideal current source has zero internal conductance.
• A closed path made of several branches of the network is known a loop.
• An ideal voltage source is that which has zero internal resistance.
• A passive network has neither source of current nor source of e.m.f. ( electro motive force).
• The relationship between voltage and current is same for two opposite directions of current in case of bilateral network.
• A passive network has neither e.m.f ( electro motive force) source nor current source.
• Heater coil is not a non-linear element.
• Milman's theorem enables a number of voltage for current source to be combined directly into a single voltage or current source.
• The thevenin's theorem is applicable to a network of the alternating current and direct current circuit both.
•  For open circuited condition of thevenin's theorem, all sources of electromotive force in the network are replaced by their internal impedance.
• Reciprocity theorem is valid for passive network only.
• In compensation theorem a network containing generator can be replaced by its zero internal impedance.
• The most important feature of superposition theorem application is to find direct current level in a network that has both sources.
• Open circuit voltage is the p.d. between two points when the impedance between these points is infinity.
• Norton's theorem reduce a two terminal network to a constant current source and an impedance in parallel.
• The superposition theorem requires as many circuits to be solved as there are sources.
• For a maximum power transfer, according to maximum power transfer theorem, source impedance must be complex conjugate of load impedance.
• In case the delta connected circuit, when one resistor is open, power will be reduced by 1/3.
• The superposition theorem is applicable to linear responses only.