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Articles by Manish Kumar Saini
Page 76 of 80
Capacitors in DC Circuits
Capacitor & CapacitanceWhen any two conducting surfaces are separated by an insulating material, it called as a capacitor. The conducting surfaces are known as plates of the capacitor and the insulating material is known as dielectric.The ability of a capacitor to store charge is termed as capacitance of the capacitor. It is denoted by C and measured in Farad (F).By experiments, it has been found that charge (Q) stored in a capacitor is directly proportional to the potential difference across it, i.e., $$Q\varpropto\:V$$$$\Rightarrow\:Q=CV$$$$\Rightarrow\:C=\frac{Q}{V}\:\:\:\:...(1)$$Where, C is a constant, known as capacitance of the capacitor.Hence, the capacitance (C) of a capacitor is ...
Read MoreCapacitor Types: Fixed & Variable Capacitors
Capacitors can be classified depending upon their fixed or variable capacitance as follows −Fixed CapacitorsThose capacitors whose value of capacitance is fixed during the manufacturing and cannot be changed later are known as fixed capacitors. The symbol of the fixed capacitor is shown in figure.The fixed capacitors are classified into two categories as −Polarized CapacitorsNon-Polarized CapacitorsPolarized CapacitorsThose capacitors which are having the specified positive and negative polarities, are called as polarized capacitors. When these capacitors are used in the circuits, they should be connected in perfect polarities.Polarized capacitors are further classified as −Electrolytic CapacitorsThose capacitors in which some electrolyte is ...
Read MoreBasics of Three-Phase Electricity
The phase-electricity is produced by a 3-phase generator that has three separate but identical windings, which are called phases. The 3-phase windings of the 3-phase generator are displaced 120° apart from each other and rotate in a common uniform magnetic field. Therefore, a three-phase generator produces three voltages of the same magnitude and frequency but 120° electrical apart from one another.Consider a three-phase alternator as shown in the figure. It has three identical windings or coils R, Y and B displaced 120° electrical from each other and rotating in anticlockwise direction with an angular velocity ω in a magnetic field ...
Read MoreAmmeter: Definition & Working Principle
An ammeter is a measuring instrument which is used for the measurement of electric current in an electric circuit.An ammeter has a low resistance. The ammeter is connected in series with the load to measure the electric current flowing through it. As, the ammeter has a very low resistance, therefore when it is connected in series with any circuit, it does not change the current.Working PrincipleWhen the ammeter is connected in series with the load, the same current flows through the ammeter that flows through the load, this is because the current in a series circuit remains same through all ...
Read MoreAlternative Ways of Generating Electricity
Apart from the conventional methods of generating electricity (like thermal, hydroelectric, gas turbine, nuclear power etc.), there are also some alternative methods of generating electricity, which are as follows −Solar PowerThe electricity can be generated from the heat of the sun. In the solar power system, the energy of sunlight is converted into electricity, either directly by the photovoltaic cell or indirectly by using concentrated solar power or combination of both.In solar power generation, the sunlight strikes onto the PV cells, which converts the energy of sunlight into direct current, that can either be stored into batteries or converted into ...
Read MoreAdvantages of Three-Phase System
Electrical power is generated, transmitted and distributed in the form of 3-phase power because it has the following advantages over the single phase system −The three phase power has a constant magnitude while the power in single phase system is the function of supply frequency i.e. pulsates from zero to maximum value at twice the supply frequency. It can be seen from the following equations, 1 − phase power, $$p=\frac{V_{m}I_{m}}{2}-\frac{V_{m}I_{m}}{2}\cos2\omega\:t$$3 − phase power, $$p=\sqrt{3}(V_{L}I_{L}\cos\varphi)$$In the 3-phase system, a rotating magnetic field can be created in stationary windings, whereas this cannot be done in a single phase system.For the same rating, ...
Read MoreAbsolute and Relative Magnetic Permeability (μ)
Absolute Magnetic PermeabilityThe absolute (or actual) magnetic permeability of a material is its conductivity for the magnetic flux. It is denoted by a Greek letter μ ‘(mu)’ and measured in Henry per meters (H/m). Thus, Absolute permeability of material, $$\mu=\mu_{0}\mu_{r}\:H/m$$Where, μ0 = absolute permeability of air or vacuum.μr = relative permeability of the material.The higher the permeability of a magnetic material, the greater its conductivity for magnetic flux and vice-versa.Air or vacuum is the poorest conductor of the magnetic flux. The absolute magnetic permeability of the air is μ0 = 4π × 10−7 H/m . The absolute permeability (μ) of a ...
Read MoreWhat is Nodal Analysis?
Nodal Analysis is a method for determining the branch currents in a circuit. In this method, one of the nodes is taken as the reference node. The potentials of all the nodes in the circuit are measured with respect to this reference node.The nodal analysis is based on the Kirchhoff’s Current Law, which states that "the algebraic sum of incoming currents and outgoing currents at a node is equal to zero".$$\mathrm{\sum\:\mathit{I}_{incoming}\:+\:\sum\:\mathit{I}_{outgoing}=0}$$Node – A node is a point in a network where two or more circuit elements meet.Junction – A junction is point where three or more circuit elements meet.In the ...
Read MoreThevenin's Theorem and Thevenin Equivalent Circuit
Thevenin’s Theorem is used, where it is desired to determine the current through or voltage across any one circuit element without going through the complex method of solving a set of network equations.Statement of Thevenin’s TheoremAny two terminal bilateral linear dc circuit can be replaced by an equivalent circuit consisting of voltage source in series with a resistance, the voltage source being the open circuited voltage across the open circuited load terminals and the resistance being the internal resistance of the source network looking through the open circuited load terminals.Explanation of Thevenin’s TheoremStep 1 – Remove the load resistor (RL) ...
Read MoreSource Transformation with Solved Examples
A practical voltage source consists of an ideal voltage source in series with an internal resistance (for an ideal voltage source, this internal resistance being zero, so that the output voltage becomes independent of the load current) While a practical current source consists of an ideal current source in parallel with an internal resistance (for an ideal current source, this parallel resistance is infinity).The practical voltage and current sources are mutually transferable i.e. a practical voltage source can be converted into a practical current source and vice-versa.Voltage to Current Source TransformationConsider a practical voltage of V volts having a series ...
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