Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Q. Draw the basic structure of an SCR and the common circuit symbol ?
The SILICON CONTROLLED RECTIFIER, usually referred to as an SCR, is one of the families of semiconductors that include transistors and diodes. A drawing of an SCR and its schematic representation is shown in views A and B of figure given below. Not all SCRs use the casing shown, but this is typical of most of the high-power units.
Although it is not the same as either a diode or a transistor, the SCR combines features of both. The basic purpose of the SCR is to function as a switch that can turn on or off small or large amounts of power. It performs this function with no moving parts that wear out and no points that require replacing. There can be a tremendous power gain in the SCR; in some units a very small triggering current is able to switch several hundred amperes without exceeding its rated abilities.
The SCR is an extremely fast switch. It is difficult to cycle a mechanical switch several hundred times a minute; yet, some SCRs can be switched 25,000 times a second. It takes just microseconds (millionths of a second) to turn on or off these units. Varying the time that a switch is on as compared to the time that it is off regulates the amount of power flowing through the switch. Since most devices can operate on pulses of power (alternating current is a special form of alternating positive and negative pulse), the SCR can be used readily in control applications. Motor-speed controllers, inverters, remote switching units, controlled rectifiers, circuit overload protectors, latching relays, and computer logic circuits all use the SCR.
Q. Explain working of three-phase transformers? Transformation in three-phase systems can be accomplished in either of two ways: (1) connecting three identical single-phase tra
Q. Discuss the disadvantages of an RC coupled amplifier? RC coupled amplifiers have a few disadvantages. The resistors use dc power and so the amplifier has low efficiency. The
Calculate the Small Signal Voltage Gain a) Calculate the small signal voltage gain a v = v o /v i , input resistance R i , and output resistance Ro for the circuit below. A
Explain in brief the functions of the clock generator chip, 8284. 8284 Clock generator: The 8284 is an ancillary element to the microprocessors. Without any clock generato
R.h. corkscrew rule Note the direction of the flux is given by Maxwell's 'R.H. corkscrew rule' and that the flux lines are continuous Applying Ampere's Law to a concentri
Explain Fourth group of 32 ASCII character code? The fourth, and final, group of 32 ASCII character codes are set aside for the lower case alphabetic symbols, five additional
Q. emf produced by windings? The time variation of emf for a single conductor corresponds to the spatial variation of air-gap flux density. By suitable winding design, the harm
A 300 km, 3-phase, 50Hz transmission line has spacing as shown in Figure. Each phase of the line consists of a bundle of three conductors. (a) Find the total per-phase inductanc
Note transducers convert a physical quantity from one form to another. The case below illustrates a typical moving coil meter that converts a current into a mechanical a
Semiconductor Devices: We have studied semiconductor devices. Firstly, we understand what semiconductors in terms of energy band diagrams are. Then we understand what is dopin
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd