The Jargon

A network is a collection of interconnected components.Network Analysis is the process of finding the voltages across, and the current through, every component in the network. Kirchhoff laws Nodal analysis Mesh analysis Source Transformation voltage division & current division Network Theorems Duality principle Network Topology Two port network Transients

Superposition theorem Thevenins & Norton's Theorem Maximum power transfer theorem Reciprocity Theorem Millimans Theorem Substitution Theorem Tellegens Theorem

Tellegen theorem states that  the summation of instantaneous powers for the n number of branches in an electrical network is zero. Suppose n number of branches in an electrical network have i 1 , i 2 , i 3 , .............i n respective instantaneous currents through them. These currents satisfy Kirchhoff's Current Law . Again, suppose these branches have instantaneous voltages across them are v 1 , v 2 , v 3 , ........... v n respectively. If these voltages across these elements satisfy Kirchhoff Voltage Law then,

It states that in a linear network any passive element can be equivalently substitute by ideal voltage source or ideal current source provided to all other branch currents and voltages doesn't change which can be possible  when the substituted element and original element absorb the same power. Substitution Theorem is the replacement of one element with another equivalent element. In a network, if any element is substituted or replaced by a voltage or current source whose voltage and current across or through that element will remain unchanged as the previous network. Example:

The  Millman's Theorem states that – when a number of voltage sources (V 1 , V 2 , V 3 ……… V n ) are in parallel having internal resistance (R 1 , R 2 , R 3 ………….R n ) respectively, the arrangement can replace by a single equivalent voltage source V in series with an equivalent series resistance R.

reciprocity theorem, in a linear passive network, supply voltage V and output current I are mutually transferable.The ratio of V and I is called the transfer resistance. In simple words, we can state the reciprocity theorem as when the places of voltage and current source in any network are interchanged the amount or magnitude of current and voltage flowing in the circuit remains the same. The various resistances R 1 , R 2 , R 3 is connected in the circuit diagram above with a voltage source (V) and a current source (I). It is clear from the figure above that the voltage source and current sources are interchanged for solving the network with the help of Reciprocity Theorem. The limitation of this theorem is that it is applicable only to single source networks and not in the multi-source network. Steps for Solving a Network Utilizing Reciprocity Theorem Step 1 – Firstly, select the branches between which reciprocity has to be established. Step 2 – The current in the branch is obtain...

The Maximum Power Transfer Theorem states that the maximum amount of power will be dissipated by a load resistance if it is equal to the Thevenin or Norton resistance of the network supplying power. The Maximum Power Transfer Theorem does not satisfy the goal of maximum efficiency. Suppose we have a voltage source or battery that's internal resistance is R i and a load resistance R L is connected across this battery.  

Thevenin’s Theorem states that any linear electrical network all the voltage sources and resistances  can be replaced by an equivalent voltage source V th in series connection with an equivalent resistance R th .       Example: If you apply source transformation technique to Thevenin's equivalent circuit then you will obtain Norton's equivalent circuit.

The response in a particular branch when all the sources are acting simultaneously is equal to the algebraic sum of individual responses by considering one source at one time. All the voltage sources are eliminated by short circuit and current sources are eliminated by open circuiting. do not disturb any dependent sources. If there are several sources acting simultaneously in an electrical circuit, then the current through any branch of the circuit is summation of currents which would flow through the branch for each source keeping all other sources dead. Example: Eliminate the voltage source by Short circuiting and find voltage and current across each branch. Finally voltage and current across each branch is given as :

Current is constant in a series circuit and voltage is constant in parallel circuit. Voltage Divider : Voltage division is the result of distributing the input voltage among the components of the divider. A simple example of a voltage divider is two resistors connected in series, with the input voltage applied across the resistor pair and the output voltage emerging from the connection between them. Current Divider : Current division refers to the splitting of current between the branches of the divider.    

Source Transformation is a simplification technique which eliminates extra nodes in a network. both the networks are equal in performance point of view but, different in connection point of view. Voltage-to-Current Source Transformation   consider a network has voltage source  Vs  in series with resistance R . then the              network   can be converted in to current source Is  with resistance in parallel with it.      the voltage source Vs can be given as : Vs =Vs / R   Current-to-Voltage Source Transformation  consider a network has current source  Is  in parallel with resistance R . then the     network can be converted in to voltage source Vs  with resistance in series with it.      the voltage source Vs can be given as : Vs =Is *R    

Mesh analysis is based on Kirchhoff Voltage Law.   It uses the mesh currents as the circuit variables. we can use Mesh Analysis to find out the voltage , current or power through a particular element or elements. Procedure for Mesh Analysis: 1. Identify all meshes of the circuit and Assign mesh currents and label polarities. for example above circuit has two meshes. mesh 1 is assigned with current I 1  and mesh 2 is assigned with current I 2 .  2. Apply KVL at each mesh and express the voltages in terms of the mesh currents. In the above circuit by applying Kirchhoff's laws we have Equation No 1 :     10 =  50I 1  + 40I 2 Equation No 2 :     20 =  40I 1  + 60I 2 3. Solve the resulting simultaneous equations for the mesh currents. We now have two “ Simultaneous Equations ” that can be reduced to give us the values     of I 1 and I 2  .

The nodal analysis and the mesh analysis are based on the systematic application of Kirchhoff’s laws . Nodal analysis is a method that provides a general procedure for analyzing circuits using node voltages as the circuit variables. Having ‘n’ nodes there will be ‘n-1’ simultaneous equations to solve. The procedure for analyzing a circuit with the node Analysis: Identify all nodes of the circuit. Select a node as the reference node also called the ground and assign to it a potential of 0 Volts. All other voltages in the circuit are measured with respect to the reference node. for example in the below circuit nodes are Va,Vb and Vc with respect to reference       node D.  According to Kirchhoff's current law   we have  I 1  + I 2  = I 3    and  I=V/R from ohm's law.    so we have  I 1  = (V a  - V b )/10 ;   I 2  = (Vc - Vb)/20 ;   I 3  = (Vb)/40 As Va = 10v and Vc = 20v  ,  Vb can be easily found by:  

Kirchhoff's Laws There are some simple relationships between currents and voltages  of different branches of an electrical circuit. These relationships are determined by some basic laws that are known as Kirchhoff laws or more specifically Kirchhoff Current and Voltage laws . These laws are very helpful in determining the equivalent electrical resistance or impedance (in case of AC) of a complex network and the currents flowing in the various branches of the network. These laws are first derived by Guatov Robert Kirchhoff and hence these laws are also referred as Kirchhoff Laws . Kirchhoff's First Law – The Current Law, (KCL) Kirchhoff's  Current Law or KCL, states that the “ total current or charge entering a junction or node is exactly equal to the charge leaving the node “. In other words the algebraic sum of ALL the currents entering and leaving a node must be equal to zero, I (entering)  + I (leaving)  = 0. This idea by Kirchhoff is commonly known as the Conservat...

The extrinsic  n Type Semiconductor  is formed, when a  pentavalent impurity  is added to a pure silicon or germanium atom in small amount and as result large number of electrons are created in it. A pentavalent impurity like phosphorous, arsenic, antimony, antimony, bismuth, lithium Antimony have having five valence electrons but, silicon or germanium need only four valance electrons. it forms four covalent bonds. But, one electron will be left excess in Antimony Thus, each Antimony atom leaves one excess electron in the germanium crystal. As an extremely small amount of Antimony impurity has a large number of atoms, therefore, it provides millions of electrons in the semiconductor. Energy band diagram :

The extrinsic  p Type Semiconductor  is formed, when a  trivalent impurity  is added to a pure silicon or germanium atom in small amount and as result large number of holes are created in it. A trivalent impurity like boron, aluminium, nitrogen, gallium, indium. have having three valence electrons but silicon or germanium have four valance electrons. so, it forms only three covalent bonds. In the   fourth covalent bond , only the germanium atom contributes one valence electron, while boron atom has no valence bonds. Hence, the fourth covalent bond is incomplete, having one electron short. This missing electron is known as a  Hole . Thus, each boron atom provides one hole in the germanium crystal. As an extremely small amount of boron impurity has a large number of atoms, therefore, it provides millions of holes in the semiconductor.

A relay is an electrically operated switch. These are remote control electrical switches that are controlled by another switch. A relay is used to isolate one electrical circuit from another. It allows a low current control circuit to make or break an electrically isolated high current circuit path. The basic relay consists of a coil and a set of contacts. The most common relay coil is a length of magnet wire wrapped around a metal core. When voltage is applied to the coil, current passes through the wire and creates a magnetic field. This magnetic field pulls the contacts together and holds them there until the current flow in the coil has stopped. The diagram below shows the parts of a simple relay. Operation: When a current flows through the coil, the resulting magnetic field attracts an armature that is mechanically linked to a moving contact. The movement either makes or breaks a connection with a fixed contact. When the current is switched off, the armature is usually returned by...

An inductor is a passive electronic component that stores energy in the form of a magnetic field. In its simplest form, an inductor consists of a wire loop or coil. The inductance is directly proportional to the number of turns in the coil. Inductance also depends on the radius of the coil and on the type of material around which the coil is wound.   The standard unit of inductance is the Henry abbreviated H. This is a large unit. More common units are the micro Henry, abbreviated µH (1 µH =10 -6 H) and the milli Henry, abbreviated mH (1 mH =10 -3 H). Occasionally, the nano Henry (nH) is used (1 nH = 10 -9 H).             inductors in series & parallel : applications : Inductors are used extensively in analog circuits and signal processing. Applications range from the use of large inductors in power supplies, which in conjunction with filter capacitors remove  fluctuations from the direct current output.          

INTRODUCTION : The capacitor is a component which has the ability or “capacity” to store energy in the form of an electrical charge producing a potential difference (Static Voltage) across its plates, much like a small rechargeable battery. CAPACITANCE : Capacitance is the electrical property of a capacitor and is the measure of a capacitors ability to store an electrical charge onto its two plates with the unit of capacitance being the FARD  (abbreviated to F ) named after the British physicist Michael Faraday. Capacitance is defined as being that a capacitor has the capacitance of One Farad when a charge of One Coulomb is stored on the plates by a voltage of One volt . Capacitance, C is always positive and has no negative units. However, the Farad is a very large unit of measurement to use on its own so sub-multiples of the Farad are generally used such as micro-farads, nano-farads and pico-farads, for example. Standard Units of Capacitance Micro farad  (μF)    1μF = 1/1,000,000...

Resistor is a two terminal passive electrical component that implants electrical resistance. in electronic circuits, resistors are used to reduce current flow. ohm's law : The behavior of an ideal resistor is dictated by the relationship specified by ohm's law. Ohm's law states that the voltage (V) across a resistor is proportional to the current (I), where the constant of proportionality is the resistance (R). resistors in series & parallel : The total resistance of resistors connected in series is the sum of their individual resistance values. The total resistance of resistors connected in parallel is the reciprocal of the sum of the reciprocals of the individual resistors. resistor color code : 1 potentiometer :  it is three terminal variable resistor.