The space or field in which a magnetic pole experiences a force is called as a magnetic field. The magnetic field can be produced either by moving the charge or some magnetic material. During the beginning of 19th century, a scientist named H. C. Oersted discovered that when current flows through a conductor, a magnetic field produces around it.Magnetic Field around a Current Carrying ConductorAs the current is defined as the rate of flow of electric charge. According to electromagnetic field theory, a moving charge produces a magnetic field which is proportional to the current, thus a carrying conductor produces ... Read More

The maximum power theorem (MPT) is used to find the value of load resistance for which there would be maximum amount of power transfer from the source to load.Statement of MPTA resistive load that is connected to a DC source, receives maximum power when the load resistance is equal to the internal resistance of the source as seen from the load terminals.Explanation of MPTConsider the following circuit diagram to determine the value of RL such that it receives maximum power from the DC source.The load current is, $$I=\frac{V_{Th}}{R_{Th}+R_{L}}$$Thus, the power delivered to the resistive load is, $$P_{L}=I^{2}R_{L}=(\frac{V_{Th}}{R_{Th}+R_{L}})^{2}R_{L}$$As we know, the ... Read More

The directed flow of charge (free electrons) is called electric current. In other words, the electric current is defined as the rate of flow charge (free electrons). It is represented by 𝐼 or 𝑖 and measured in Amperes (A). i.e.$$I=\frac{Q}{t}=\frac{ne}{t}\:\:Ampere(A)$$Where, Q = ne, and e = 1.6 X 10-19 C.In differential form, $$i=\frac{dq}{dt}$$How electric current flows?In the figure, the copper conductor has a large number of free electrons. When a potential difference (voltage) is applied across it, the free electrons (negatively charged) starts moving towards the positive terminal of the source. This directed flow free electrons is called as electric ... Read More

Electrical Circuit Devices are essential components of electrical and electronic circuits. There are several devices that are present in electrical and electronic circuits. Some important circuit devices are as follows −SourcesSwitchesConnectorsCircuit Protection DevicesLoadsSourcesA source of electrical energy is a device that delivers energy into a system. These devices create potential difference, which in turn causes electric current to flow in a circuit. Examples of typical electrical sources include Generators, Cells, Batteries and Photovoltaic Cells etc.Generators – There are two types of electric generators viz. AC generator and DC generator.Cells and Batteries – An Electrical cell is a device which can ... Read More

To understand the transient response of the second order system, consider the block diagram of closed loop system with unity negative feedback.The open loop transfer function of the second order system is given by, $$G(s)=\frac{\omega_{n}^{2}}{s(s+2\zeta\:\omega_{n})}$$And the closed loop transfer function of the second order system is given by, $$\frac{C(s)}{R(s)}=\frac{G(s)}{1+G(s)}=\frac{\omega_{n}^{2}}{s^{2}+2\zeta\:\omega_{n}s+\omega_{n}^{2}} \:\:\:\:...(1)$$Where, R(s) = Laplace transform of the input signal r(t), C(s) = Laplace transform of the output signal c(t), ξ= Damping Ration, Ωn = Natrural frequency of oscillations.As from the equation (1), we can see, the power of s is two in the denominator term. Thus, the transfer function represents a second ... Read More

Concept of Electromotive Force (EMF)The electromotive force (EMF) of a source, is a measure of the energy the source gives to each coulomb of charge. The EMF is measured in volts (V).At first sight, the name EMF implies that it is a force that causes the current to flow but this not correct, because it is not a force but energy supplied to the charge by some source of energy such as a battery. The EMF maintains potential difference while the potential difference causes current to flow.Difference between EMF and Potential DifferenceAs we know, the EMF of the battery is ... Read More

The superposition theorem is used in solving a network in which two or more sources are present and connected not in series or in parallel.Statement of Superposition TheoremIf two or more voltage or current sources are acting simultaneously in a linear network, the resultant current in any branch is the algebraic sum of the currents that would be produced in it, when each source acts alone and all other independent sources are replaced by their internal resistances.Explanation of Superposition TheoremIn the circuit given below, we have to find the branch currents viz. i1, i2, i3 by using superposition theorem.Step 1 ... Read More

A Voltaic cell is an electrochemical cell that converts the chemical energy of spontaneous (natural) redox reactions into electrical energy. The Voltaic cell is also called as Galvanic cell.The voltaic cell is named after its inventor Alessandro Volta in 1799.In redox (oxidation-reduction) reactions, the electrons are moved between two different species and if these reactions occur spontaneously then energy is released as a result of these reactions. Therefore, the released energy is used to do work. To deal with this energy, it is necessary to split the reaction into two half reactions – Oxidation and Reduction. By using two different ... Read More

ResistorThe measure of opposition offered by the substance in the flow electric current is known as Resistance of the substance and the element that possess the resistance is called a Resistor. The circuit symbol of resistor is shown in the figure below.Types of ResistorsThe resistor are broadly classified into two types –Fixed ResistorsVariable ResistorsFixed ResistorsThe fixed resistor is defined as the resistor whose resistance value does not change with the any change in temperature or voltage. These resistors are available in different shapes and sizes. The main function of an ideal fixed resistance gives a stable resistance in all situations. ... Read More

A wattmeter is an instrument which is used to measure electric power given to or developed by an electrical circuit. Generally, a wattmeter consists of a current coil and a potential coil.Types of WattmeterElectrodynamometer wattmeter – for both DC and AC power measurementInduction wattmeter – for AC power measurement onlyWorking Principle of Electrodynamometer WattmeterThe electrodynamometer wattmeter works on the dynamometer principle i.e. a mechanical force acts between two current carrying conductors or coils.It consists of a fixed which is divided into two halves which are parallel to each other and is connected in series with the load while the moving ... Read More