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Showing posts with the label Electrical Engineering

Multiplexer Definition, Types, Uses

Multiplexer The multiplexer is a device that has multiple  inputs and a single line output. The select lines determine  which input is connected to the output, and also to increase  the amount of data that can be sent over a network within a  certain time. It is also called a data selector. The single pole multi-position switch is a simple  example of a non-electronic circuit of the multiplexer. Multiplexers  are capable of handling both analog and digital applications. In analog applications, multiplexers are made up of relays  and transistor switches, whereas in digital applications, the  multiplexers are built from standard logic gates. When the  multiplexer is used for digital applications, it is called a digital multiplexer. Multiplexer Types Multiplexers are classified into four types: 2-1 multiplexer (I select line) 4-1 multiplexer (2 select lines) .8-1 multiplexer (3 select lines) 16-1 multiplexer (4 select lines) Uses of Multiplexers A Multiplexer is used in various applicatio

Klydonograph In Electrical Engineering

Klydonograph The Klydonograph to the measurement of voltages-surge on transmission lines. Klydonograph  is placed directly on the line. From the shape and size of the figure, an estimate regarding the magnitude, wave front, and polarity of the wave can be made. It is a device that makes use of patterns known as Lichtenberg Figure Which are produced on photographic in by surface corona discharge. Since lighting surge is infrequent ( rare ) and random in nature. Hence it is necessary to install a large no. of recording devices to obtain a reasonable amount of data regarding these surges produced on transmission lines and other equipment Klydonograph Diagram It Is consists of around electrode resting on the emulsion side of photographic plates. Klydonograph Diagram shown in Figure (2.25). The homogenous insulating plate is placed between the photographic plate and a metal plate electrode. This insulating plate has a smooth surface. When an electric held is applied betw

What is Fermi level

What is the Fermi level?  As discussed in the energy band theory of crystals, we know that N energy levels exist for an intrinsic  semiconductor. Out of which 4N energy levels (or energy states) lie in the valence band and the remaining 4N states lie in the conduction band. At 0°K, all 4N states of the valence band are completely filled while 4N energy levels of the conduction band are entirely empty.  Therefore, out of allowed 8N energy levels, only 4N energy levels are filled. Thus, the probability of energy levels being filled is 50% (4N/8N-05) This probability is shown in the energy band diagram by a new imaginary energy level called the Fermi level' (Ep).  Since probability is 50% for intrinsic semiconductors at 0°K, therefore, level (EF) located in the Centre is a forbidden energy gap [Figure 1.21 (a)] For a probability of 70% and 30%, the Fermi levels will be located as shown in figure 1.21(b) and figure 1.21(c) respectively. Fermi Level In Extrinsic Semiconductors (A) N-typ

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

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