Electric NetworkAn electrical network is an interconnection of electrical components (like sources, resistors, inductors, capacitors, diodes, transistors etc.). An electrical network need not contain a closed path for the flow of electric current. Some examples of the network are shown in the figure given below.Characteristics of Electric NetworkAn electric network possesses the following characteristics −It is an interconnection of electrical components.Electric network need not provide a return path for the current.It may or may not contain active electrical components.It may be consist of, passive elements, active elements or both active and passive elements.Examples of electric network are − Resistive network, ... Read More

Consider the circuit consisting of a capacitor (C) only. When an alternating voltage is applied across the capacitor, the capacitor being charged in one direction and then in the other as the voltage reverses. Due to the application of alternating voltage across the capacitor the electrons move to and fro around the circuit, thus constituting alternating current.Let the equation of the applied alternating voltage is$$\mathrm{u= V_{m} sin(\omega t)}\:\:\:….. (1)$$As a result of the alternating voltage (v), alternating current will flow through the circuit (i). Let at any instant q is the charge on plates of the capacitor. Thus, $$\mathrm{q=C u ... Read More

MultimeterAs the name implies, a multimeter is device that can be used to measure multiple quantities, i.e., when a single device is used to measure multiple quantities, the device is called multimeter. On the basis of output representation, there are two types of multimeters −Analog multimeterDigital multimeterAnalog MultimeterAn analog multimeter is a permanent magnet moving coil (PMMC) meter type measuring instrument. It works on the principle of d’Arsonval galvanometer. The analog multimeter has an analog display that uses the deflection of a pointer on the scale to indicate the level of measurement being made. The pointer deflects from its initial ... Read More

Average Value of Alternating QuantityThe arithmetical average of all the instantaneous values of an alternating quantity over one cycle is known as the "Average Value of Alternating Quantity".$$Average\:value=\frac{Sum\:of\:all\:instantaneous\:values\:over\:one\:cycle}{Number\:of\:instants}$$$$=\frac{Total\:are\:under\:the\:curve\:for\:time\:period\:T}{Time\:Period\:(T)} $$$$=\frac{i_{1}+i_{2}+i_{3}+...+i_{n}}{n}$$Average Value of Symmetrical WavesIn case of symmetrical waves like sinusoidal voltage or current, the average value over one cycle is zero. It is because the positive half cycle is exactly equal to the negative half cycle. But the average value of positive or negative half cycle is not zero. Therefore, in case of symmetrical waves, the average value is calculated for half cycle.$$Avg\:value = \frac{Sum\:of\:all\:instantaneous\:values\:over\:half\:cycle}{Number\:of\:instants\:of\:half\:cycle}$$Average Value of Unsymmetrical WaveIn case of ... Read More

A unit of measurement can be defined as a quantity chosen as a standard in terms of which other quantities may be expressed.Engineering is an applied science dealing with a variety of physical quantities (a physical quantity is one which can be measured) like time, speed, voltage, resistance etc. Hence, for the measurement of these quantities standard units are defined.There are a number of electrical units defined which are based on the SI system of units.Standard Electrical Units of MeasurementElectrical QuantitySymbol for QuantityMeasuring UnitSymbol for UnitChargeQ or qCoulombCVoltageV or vVoltVEMFE or eVoltVCurrentI or iAmpereAResistanceR or rOhmΩInductanceLHenryHCapacitanceCFaradFConductanceGMho or Siemen℧ or Ω-1or ... Read More

A band pass filter (BPF) is a circuit that passes frequencies within a certain range and rejects all the frequencies outside the range. This range of band pass filter is known as Bandwidth of the filter.The Bandwidth of band pass filter is given by, $$Bandwidth=f_{high}-f_{low}$$Where, fhigh and flow are the higher and lower cut off frequencies.The values of fhigh and flow are given by, $$f_{high}=\frac{1}{2\pi\:R_{2}C_{2}}$$$$f_{low}=\frac{1}{2\pi\:R_{1}C_{1}}$$In the frequency response curve or bode plot of the band pass filter, the signal is blocked(attenuated) at low frequencies with the output increasing at the rate of +20dB/Decadeuntil the frequency reaches the Lower Cut off ... Read More

Wires and TracesComponent NameSymbolWires or ConductorTrace Junction or Connected WiresTrace Crossing or Unconnected WiresGroundsComponent NameSymbolGround or EarthSignal GroundChassis GroundSourcesComponent NameSymbolSingle CellBattery (Combination of cells)Photovoltaic Cell (Solar Cell)Independent or Constant Voltage SourceControlled or Dependent Voltage SourceIndependent or Constant Current SourceControlled or Dependent Current SourceAC voltage SourceResistorsComponent NameSymbolFixed ResistorRheostat (Variable Resistor)PotentiometerThermistor or VaristorCapacitorsComponent NameSymbolNon-polarized CapacitorPolarized CapacitorVariable CapacitorTrimmer CapacitorInductorsComponent NameSymbolAir Cored InductorIron Cored InductorTapped InductorTransformersComponent NameSymbolTransformerCenter Tapped TransformerStep up TransformerStep Down TransformerTransformer with two secondary windingsCurrent TransformerPotential TransformerZero Sequence Current Transformer (ZSCT)DiodesComponent NameSymbolPN Junction DiodeSchottky DiodeZener DiodeLight Emitting Diode (LED)Photo DiodeTunnel DiodeVaricap (Variable Capacitor Diode)Schockley DiodeConstant Current DiodeSilicon Controlled Rectifier (SCR)DiacTransistorsComponent NameSymbolN-channel, Junction ... Read More

An electrodynamometer or simply Dynamometer wattmeter is an instrument that is universally used for the measurement of DC as well as AC electric power.It works on the principle of dynamometer i.e. a mechanical force acts between two current carrying conductors.Construction of ElectrodynamometerThe electrodynamometer wattmeter has a fixed coil divided into two parts and is connected in series with the load and caries the load current (I1). The moving coil is connected across the load through a series multiplier resistance (R) and carries a current (I2) proportional to the load voltage. The fixed coil is called as Current Coil and the ... Read More

A magnet whose magnetic field is created by an electric current is known as Electromagnet. An electromagnet consists of a soft iron core wound with a coil of conductor wires.When a direct electric current is passed through the coil of the electromagnet a magnetic field is created around it. Since the magnetic field of electromagnet is a function of electric current flowing through the coil hence, the magnetic field can be alter by changing the amount of electric current. And its polarity can be changed by changing the direction of electric current.Electromagnets are temporary magnets because they can be demagnetized ... Read More

To understand the transient response of the first order system, consider the block diagram of a closed loop system with unity negative feedback.The open loop gain G(s) of the system with unity negative feedback is given by, $$G(s)=\frac{1}{s\tau}$$And the closed loop transfer function of the system with unity negative feedback is, $$\frac{C(s)}{R(s)}=\frac{G(s)}{1+G(s)}=\frac{1}{s\tau+1}\:\:\:...(1)$$Where, R(s) = Laplace transform of the input signal r(t), C(s) = Laplace transform of the output signal c(t), τ = Time Constant of the system.As we can see, the power of s is one in the denominator term of the closed loop transfer equation. Hence, the system is said to ... Read More