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Showing posts with the label Electrical Engineering

Light Emitting Diode - Definition, Construction, Working, Applications

Light Emitting Diode Definition A light-emitting diode (LED) is a diode that emits light when a current passes through it in the forward direction. It is a very useful display device. LED's are available which emit light in different colors like red, green, yellow. orange and white. Construction Of Light Emitting Diode LED is a P-N junction diode. It is made up of gallium arsenide (GaAs) or gallium phosphide (GaP) or gallium arsenide phosphide (GaAsP). Metal contacts are made both on the P and N sides for external connection to the battery. The conducting surface connected to the P-material is much smaller. to permit the emergence of maximum light. LED is a direct bandgap type diode Working Principle Of Light Emitting Diode When an electron is excited from the valence band to the conduction band, the electron and hole pairs are created as  shown in Figure 4.12. Electron stays in conduction band for a very short period called life time109 sec) and then returns back. In the transitio

Read-Only Memory (ROM) - Meaning, Types, Advantages

Read-Only Memory (ROM) ROM remains for Read-Only Memory. The memory from which we can only read however can't compose on it. ROM is a kind of memory that is non-unpredictable. The data is put away for all time in such recollections amid fabricate. The function of Read-Only Memory A ROM stores such directions that are required to begin a PC. This activity is alluded to as bootstrap. ROM chips are utilized as a part of the PC as well as in other electronic things like clothes washers and microwaves.  Types of Rom 1. MROM (Masked ROM)  The simple first ROMs were hard-wired gadgets that contained a pre-modified arrangement of information or guidelines. These sort of ROMs are known as concealing ROMs, which are modest.  2. PROM (Programmable Read-Only Memory)  PROM is read-only memory that can be altered only once by a client. The client purchases a clear PROM and enters the coveted substance utilizing a PROM program. Inside the PROM chip, there are little breakers that are singed ope

Reluctance Motor - principle, Working, Advantages

Reluctance Motor The stator has the main winding and an auxiliary (starting) winding. In general, the stator of a single-phase reluctance motor is similar to that of any one of the single-phase induction motors. The rotor of a reluctance motor is basically a squirrel cage with some rotor teeth removed at the appropriate places such as to provide the desired number of  salient rotor poles. Figure 9.1 shows the 4- pole reluctance type synchronous motor. Her teeth have been removed in four locations to produce a 4-pole salient-pole structure. The rotor bars are kept intact even in the spaces from where teeth are removed. The two end rings short-circuit these bars as in a cage rotor. Working principle Of Reluctance Motor When the stator is connected to a single-phase supply, the motor starts as a single-phase induction motor. At a speed, of about 75 percent of the synchronous speed, a centrifugal switch disconnects the auxiliary winding, and the motor continues  to speed up as a single-pha

Photodiode - Definition, Principle, Applications

Photodiode Definition of  Photodiode The photodiode is an optoelectronic device whose region of operation is limited to the reverse bias region. It carries current in reverse bias condition that depends upon the intensity of light falling on a P-N junction Principle of Photodiode The photodiode is a simple P-N junction diode that is reverse biased with a battery of voltage V (Figure 4,9) Under normal conditions, a reverse saturation current (lo) flows due to thermally generated minority carriers. It is called dark current. The reverse saturation current is independent of applied reverse voltage (reverse voltage opposes the flow of majority carriers and diffusion of minority carriers is unaffected). Minority carrier depends upon temperature, therefore, reverse solution current is a function of temperature When light falls at the P-N junction, light photons impart their energy to valence electron to break the covalent bond. So electron and hole pairs are generated and their concentration

Depreciation Definition, Types And Causes

Depreciation Depreciation is taken from the Latin word Depretium. De Means Decrease and premium mean price. Thus the meaning of Depreciation is decreased in princes. The reduction value of equipment and building is known as Depreciation. Normally the power plant has age is 50 to 60 years. after the useful life, we need to maintain or change the machine or equipment of the power plant. Thus to change the machine or equipment we have to save the money, this is the amount which is saved every year known as the Depreciation charge. Types of Depreciation Method 1. Straight-line method The straight-line method is a simple method to calculate  depreciation. In this method, we calculate the amount based on the initial cost divided by the useful life of the equipment if the salvage value is zero. If a salvage value is few amounts then we subtract the initial value to the salvage value and divide it by useful life. Depreciation charge = initial value  - salvage value / Useful life Straight-l

Job interview Questions For Electrical Engineer

Job interview Questions  Essential Electrical Engineering questions and answers center around all zones of Basic Electrical Engineering subject covering in Basic Electrical Engineering. These points have browsed an accumulation of the most legitimate and best reference books on Basic Electrical Engineering. 1. Why is RC coupling called so? Ans. It is because in this arrangement the voltage developed across collector load (RC) in one stage is coupled through a capacitor (CC) to the next stage. 2. Why is RC coupling employed in the initial stages of a multistage amplifier? Ans . The initial stages of a multistage amplifier are required to do the job of voltage amplification and this is aptly done by RC coupling due to the least frequency distortion. However, the final stage is expected to deliver maximum power to the output device e.g. speaker. For this purpose, impedance matching is the required-a quality which an RC coupled amplifier does not possess because of its output. impedance i

Rotameter - Principle, Working, Advantages

Rotameter Rotameter is a device that measures the flow rate of liquid or gas in a closed tube. It consists of a tube and float. The rotameter is standard as a result of its linear scale, relatively long measurement range, and low-pressure drop. It is very simple to install and maintain.  In the construction of the rotameter tube, it is marked in the division, and the reading of the meter is obtained from the scale reading at the reading edge of the float, which is taken at the largest cross-section of the float. Rotameter Is Used The rotameter is an Associate in Nursing industrial flowmeter wont to live the flowrate of liquids and gases. The rotameter consists of a tube and float. The float response to flow rate changes is linear, and a 10-to-1 flow varies or nonacceptance is customary. within the case of OMEGA™ laboratory rotameters, so much larger flexibility is feasible through the utilization of correlation equations. The rotameter is standard as a result of its linear scale, a c

What Is Coherence In Physics

Coherence In Physics Two waves are said to be coherent if they have the same frequency (or wavelength) and are in phase ( or have a constant phase difference between them). The coherence of a wave depends on the characteristics of its supply. The light produced by lasers is coherent light. Light from light bulbs or the sun is incoherent light. A high  coherence means high fringe visibility with excellent contrast (i.e. good black and white fringes or black and whatever color the light is) and low coherence means washed out fringes and zero coherence means no fringes. Another necessary condition (for waves to be coherent) is therefore that both waves travel at the same speed. It can be well understood from Fig. (1) and (2). Fig. ( 1) shows a typical beam of light waves from an ordinary source traveling through space. It is a concept that establishes the limits within which a real light source can be considered ideal. It is a measure f the correlation that exists betwee

Corona Effect In Transmission Line

Corona Effect Electric power transmission for all intents and purposes manages the mass exchange of electrical vitality, from creating stations arranged numerous kilometers from the fundamental utilization focuses or the urban communities. Thus, the long-separate transmission links are of the most extreme need for effective power exchange, which in-obviously results in colossal misfortunes over the framework. Limiting those has been a noteworthy test for control architects generally and to do that one ought to have an unmistakable comprehension of the sort and nature of misfortunes.  High voltage control transmission, a substantial power conveyed through the conductor. At the point when the power is exchanged through the conductor, the voltage awe between the conductor and air will make a capacitance for the line. The marvels of violet gleam, murmuring clamor, and production of the ozone gas contained in the overhead transmission lines are typically favored as the corona effect  in the

Feedback Amplifier Topologies

Feedback Amplifier Topologies Negative criticism in an enhancer is the strategy for sustaining a segment of the opened-up yield to the information yet in the inverse stage. The stage restriction happens as the intensifier gives the 180 stage move through the criticism arrange doesn't.  While the yield vitality is being connected to the contribution, for the voltage vitality to be taken as input, the yield is taken in shunt association and for the present vitality to be taken as criticism, the yield is taken in arrangement association.  Two negative input circuits 1. Negative Voltage Feedback  2. Negative Current Feedback  Negative Voltage Feedback  In this technique, the voltage criticism of the contribution of the enhancer is relative to the yield voltage. This is additionally grouped into two sorts −  1. Voltage-arrangement criticism  2. Voltage-shunt criticism    Negative Current Feedback  In this technique, the voltage criticism to the contribution of the intensifier

Advantages of Stationary Armature

Advantages of Stationary Armature The field twisting of an alternator is p ut on the rotor and is associated with DC supply through two slip rings. The 3-phase armature winding is set on the stator. The advantages of Stationary Armature are the Following. 1.     It is easier to insulate stationary winding for high voltages for which the alternators are usually designed. 2.     It is on the grounds that they are not exposed to diffusive powers and furthermore additional room is accessible because of the stationary course of action of the armature. 3.     The stationary 3-phase armature can be directly connected to load without going through large, unreliable slip rings and brushes. 4.     Only two slip rings are required for DC supply to the field winding on the rotor. Since the exciting current is small, the slip rings and brush gear required are of light construction. 5.     Due to the simple and robust construction of the rotor, the higher speed of rotating DC the field is possible.

Torque Converter - Working, Diagram, Function, Problems

Torque Converter The torque converter is a device used to the multiplication of torque. It consists of: (i) The impeller or the driving member, (ii) The turbine or driven member, (iii) The stator fixed to the frame through a freewheel. Torque Converter Diagram Torque Converter Operation Torque Converter Working  When the engine is started, the impeller starts rotating, the oil from the impeller is pushed into the turbine. The oil, having high kinetic energy from the engine through the impeller hits the outer edge of the turbine. This force will increase with the rise of engine speed. once it's nice enough the turbine starts rotating and therefore the vehicle moves. The fluid from the turbine is made to strike a stator, which changes it’s direction suitably so that the oil leaving g the stator strike the impel [er in a favorable direction i.e. in the same direction in which the impeller is turning. Thus repeated pushing of the turbine blades causes the torque on the turbine to incre