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Thyristor can only be turned on by small gate pulse but it cannot be turn off by using gate hence thyristor is called semi controlled device.
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Answer : Thyristor can be turn on by positive gate pulse and the current will continue to flow through the device even when the gate voltage is low hence thyristor is called latching device.

Answer : already answered here is mosfet current controlled device?

Answer : No, IGBT is not the current controlled device. IGBT is a voltage controlled device. IGBT have combine qualities of MOSFET and BJT. The high switching speed of MOSFET and low conduction losses of BJT. Also, IGBT which stands for Insulated Gate Bipolar Transistor have high input impedance.

Answer : No, BJT is a current controlled device .

Answer : BJT is current controlled device.

Answer : In  BJT  there  is  movement  of   electrons  and  holes   accros  the  junctions  which  is  basicaly  current  flow.

Description : what is TCSC?

Answer : Thyristor Controlled Series Capacitor (TCSC)

Description : Why transistor is called as bipolar device.

Answer : BJT is called bipolar device because in BJT current conduction takes place due to majority as well as minority charge carriers that is because of electrons as well as holes.

Description : Why SCR is called as thyristor?

Description : Why thyristor are not preferred for inverter?

Description : parallel operation of MOSFET can be done more easily as compared to thyristor. why?

Answer : Parallel operation of MOSFET can be done more easily as compared to thyristor because the resistance of MOSFET is increases with increase in temperature. MOSFET have the positive temperature coefficient. In ... the parallel operation of MOSFET can be done more easily as compared to the thyristor.

Answer : Thyristor have three terminals anode, cathode and Gate.

Description : thyristor can be turned off by?

Answer : Thyristor can be turned off by making anode potential equal to cathode potential or by making anode potential less than cathode potential.

Answer : Thyristor commutation means turning off thyristor.

Description : Application one lamp controlled from two places

Answer : Application one lamp controlled from two places: 1. For Stair case wiring 2. Hospital Wiring ( For operating the lamp in room and nursing station) 3. Bedroom Lighting. 

Description : How are nuclear reactors controlled? Explain two different methods in brief.

Answer : Nuclear reactor is controlled using control rods: Control rods are made up of very high neutron absorbing material like boron, cadmium. By adjusting height of control rods on reactor core ... of nuclear reaction will increase. Whereas by pushing control rod towards the core it will reduce.

Description : A current controlled voltage source is equivalent to :  (A) series voltage feed -back amplifier (B) shunt current feed -back amplifier (C) shunt voltage feed -back amplifier (D) series current feed -back amplifier

Answer : A current controlled voltage source is equivalent to : shunt voltage feed -back amplifier

Description : State any four materials used in fabrication of semiconductor device and describe its need.

Answer : For fabrication of semiconductor devices like transistors diode, solar cell etc. we have to make use of following types of materials  1. Substrate: o It is used for deposition of thin ... . o Metal cans and sealed glass containers satisfy the extreme requirements of space and military users.

Description : Linear and non-linear device

Answer : Linear and non-linear device

Description : Describe the working principle of Thyristor operated dimmer with the help of circuit diagram.

Answer : Thyristor operated dimmer: A popular thyristor operated dimmer circuit employ TRIAC-DIAC phase control for low AC power control. During each half-cycle, the capacitor charges through (R1+VR1). When the ... time constant {C (R1+VR1)}. Thus by reducing VR1 the lamp brightness can be increased.

Description : Thyristor can be protected from over voltages by using

Answer : Thyristor can be protected from over voltages by using Voltage clamping device

Description : Leakage current flows through the thyristor in

Answer : Leakage current flows through the thyristor in Forward blocking mode and Reverse blocking mode.

Description : What is a phase control thyristor?

Description : What is thyristor family?

Description : What is meant by firing angle of thyristor?

Answer : The point at which SCR is triggered is known as firings angle of thyristor.

Description : What is the use of a thyristor in a circuit?

Description : What is a reverse conducting thyristor?

Description : What is the function of a thyristor?

Description : Is a SCR a thyristor?

Answer : Yes, SCR is a thyristor. Thyristor is the family and SCR is the member of that family but SCR is universally known as thyristor.

Description : How is a thyristor used to convert AC to DC?

Description : What is the application of thyristor?

Answer : Yes ,it is one of the main advantage using thristors as a  switch in DC  circuit ,it has a high current gain

Description : Explain thyristor gate drive circuit.

Answer : Thyristor Gate Drive Circuit: The thyristor can be turned on by pulse voltage signal at gate terminal and it does not require continuous drive signal like the transistor. The gate ... circuit provide required minimum gate voltage and gate current then the thyristor conducts properly.

Description : what are the disadvantages of thyristor?

Answer : Disadvantages of thyristor The silicon controlled rectifier (SCR) is unidirectional devices, so it can control power only in DC power during positive half cycle of AC supply. Thus only DC power is ... cycle. It cannot be used at higher frequencies. The gate current cannot be negative

Description : write short notes on thyristor CSI .

Answer : Current-source inverter (CSI) is an inverter with a DC current input. Current source inverters are most commonly used in very high power AC motor drives.

Answer : By using some circuit the forward DC current of thyristor is forced to zero is called forced commutation.

Answer : Natural commutation is also called as line Communication. The turning off of thyristor due to AC supply is called natural commutation or line commutation. If the thyristor is connected to AC supply ... connected to positive and anode terminal get connected to negative, this turns off the thyristor.

Answer : No we cannot turn off normal thyristor using Gate.

Answer : Thyristor conducts when the anode voltage is greater than cathode and when the current provided to Gate.

Description : Thyristor Switched Capacitor (TSC)

Answer : Thyristor Switched Capacitor (TSC)  TSC is a static compensator. TSC is use for compensating reactive power. Compensation is required for voltage regulation, increasing stability, ... compensating device like TCS phase angle between voltage and current can be maintain.

Description : Draw the structural diagram of GTO. Explain briefly the switching behavior of GTO with the help of appropriate voltage and current waveform.

Answer : Gate Turn Off Thyristor (GTO) Conventional Thyristor can be turned on with gate terminal but can not turn off from gate terminal. But in case of Gate Turn Off Thyristor (GTO), we can turn it on and off ... subdivided as storage period (Ts), fall period (Tp) and tail period (Tt).

Description : State classification of Phase controlled rectifiers.

Answer : Classification of phase controlled rectifiers:

Description : Single-phase mid-point controlled rectifier with RL load

Answer : Single-phase mid-point controlled rectifier with RL load : The circuit configuration of single-phase midpoint controlled rectifier is shown in the figure. During positive half-cycle of ... some part of next positive half-cycle of voltage with reversed polarity can appear across load.

Description : Single-phase Midpoint controlled rectifier with Resistive load

Answer : Single-phase Midpoint controlled rectifier with Resistive load:  1) During positive half cycle of AC supply, a is positive with respect to b , this makes T1 forward biased and T2 is reverse ... voltage reverses the polarity and T2 is turned off. The operation is as shown in waveforms.

Description : Give the operation of single phase full wave bridge controlled converter with RL load with a neat diagram. Also draw its waveform.

Answer : Single phase fully control bridge converter with RL load: 1. During positive half cycle of input voltage, T1 and T2 are forward biased and during negative half cycle, T3 and T4 are forward biased. Therefore, T1-T2 ... cycle till the firing of next pair of SCRs as shown in the waveform.

Description : Draw a neat diagram of 1Ф half wave controlled converter with RL load. Give its operation.

Answer : Single phase fully controlled half wave converter:  The circuit diagram of single-phase half-wave controlled rectifier with RL load and without freewheeling diode is shown in Fig. (a). The SCR T is ... , when again pulse is applied, the SCR is turned on & the above cycle is repeated. 

Description : The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque  (1) Decreases (2) Increases (3) Remains constant (4) None of the above

Answer : The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque Increases 

Description : A 3 -phase, fully controlled, converter is feeding power into a DC load at a constant current of 150 A, the rms value of the current flowing through each thyristor of the converter is

Answer : A 3 -phase, fully controlled, converter is feeding power into a DC load at a constant current of 150 A, the rms value of the current flowing through each thyristor of the converter is 150/√3

Description : When the firing angle a of a single-phase, fully controlled rectifier feeding constant direct current into a load is 30°, the displacement power factor of the rectifier is

Answer : When the firing angle a of a single-phase, fully controlled rectifier feeding constant direct current into a load is 30°, the displacement power factor of the rectifier is √3/2

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