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.
asked
Mar 19, 2018
by
anonymous
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.
asked
Dec 7, 2017
by
anonymous
Description : Why thyristor are not preferred for inverter?
asked
Mar 19, 2018
by
anonymous
Answer :
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.
asked
Sep 10, 2017
by
anonymous
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.
asked
Sep 10, 2017
by
anonymous
Description : SCR is more utilized as compared to Triac because it is
Answer :
SCR is more utilized as compared to Triac because it is available with higher ratings
asked
Apr 29, 2018
by
anonymous
Description : An SCR without any external connections is considered as (A) two diodes in series (B) three diodes in series (C) two n-p-n transistors in series (D) two p-n-p transistors in series
Answer :
An SCR without any external connections is considered as three diodes in series
asked
Apr 28, 2018
by
anonymous
Description : Explain triggering of SCR using opto-coupler. State its advantages.
Answer :
Triggering of SCR using opto-coupler: A simple opto-coupler based triggering circuit for SCR is shown in the figure. An optocoupler or opto-isolator is a combination of light source ... is small size and light weight device. iii)Interfacing with logic circuits is easily possible.
asked
May 21, 2020
by
anonymous
Description : Draw the circuit diagram of battery charger using SCR and explain it’s working.
Answer :
Battery charger circuit using SCR: The figure shows the battery charger circuit using SCR. A 12V discharged battery is connected in the circuit and switch SW is closed. The singlephase 230V ... not fired. In this way, after full charging, further charging is automatically stopped.
asked
May 21, 2020
by
anonymous
Description : Explain the thermal triggering method of SCR. Enlist different triggering methods of SCR.
Answer :
Types of Triggering: 1) Forward voltage triggering 2) Thermal triggering (Temperature triggering) 3) Radiation triggering (Light triggering) 4) dv/dt triggering 5) Gate triggering ... generated leakage current increases. This current gets multiplied internally and thyristor is turned on.
asked
May 21, 2020
by
anonymous
Description : Explain working of AC circuit breaker using SCR with circuit diagram.
Answer :
AC Circuit Breaker: The circuit configuration of static AC circuit breaker using SCR is shown in the figure. When switch S' is closed, the SCRs T1 and T2 are fired in positive ... to non-availability of gate current. Thus the maximum time delay for breaking the circuit is one half-cycle.
asked
Oct 13, 2019
by
anonymous
Description : Temperature controller using SCR
Answer :
Temperature controller using SCR The temperature control circuit is used to regulate the temperature. Figure shows the temperature control circuit using thermostat as temperature detector and SCR as ... half-cycle and heater gets connected to source to produce heat and raise the temperature.
asked
Oct 13, 2019
by
anonymous
Description : Compare SCR and TRIAC
Answer :
SCR TRIAC It is an unidirectional device. It is a bidirectional device. It is turned-on by only positive gate current. It can be turned-on by either ... applications including lamp dimmer, heating control, zero voltage switched AC relay, small AC motor control etc.
asked
Oct 13, 2019
by
anonymous
Description : Describe triggering of SCR using UJT relaxation oscillator.
Answer :
Triggering of SCR using UJT relaxation oscillator:
asked
Oct 13, 2019
by
anonymous
Description : How GTO is advantages over SCR
Answer :
i) It is turned-off by negative gate pulse. ii) No commutation circuit required, reducing the cost, size, weight and volume of the circuit. iii) As commutation choke is not used, the associated acoustic ... turn off time permits high switching frequency. v) It has higher di/dt rating at turn-off.
asked
Oct 13, 2019
by
anonymous
Description : Draw a neat labelling V-I characteristics of SCR and explain the region
Answer :
(i) Latching current: It is the minimum anode current required to maintain the SCR in the conduction state just after turn-on and the gate signal has been removed. (ii) Holding current: It is the minimum anode current required to hold the conducting SCR in the ON state.
asked
Jul 25, 2019
by
anonymous
Description : Draw construction of SCR using two transistor model. Explain its operation.
Answer :
Two Transistor Model of SCR or Thyristor
asked
Jul 25, 2019
by
anonymous
Description : The SCR would be turned OFF by voltage reversal of applied anode-cathode ac supply frequency of A) 10 kHz B) 10 Hz C) 5 kHz D) 5 Hz
asked
Jun 18, 2018
by
anonymous
Description : A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc current. If the source inductance is 3 mH, the drop in dc output voltage is (A) 4.5 V (B) 6.75 V (C) 9 V (D) 13.5 V
Answer :
A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc current. If the source inductance is 3 mH, the drop in dc output voltage is 9 V
asked
Apr 28, 2018
by
anonymous
Description : In a 230 V, 50 Hz single-phase SCR bridge converter operating at a firing delay angle, α and with large R-L load, the input source current is (A) sinusoidal current (B) constant dc current (C) continuous rectangular pulses (D) alternating rectangular pulses
Answer :
In a 230 V, 50 Hz single-phase SCR bridge converter operating at a firing delay angle, α and with large R-L load, the input source current is alternating rectangular pulses
asked
Apr 28, 2018
by
anonymous
Answer :
Yes, SCR is a unidirectional switch.
asked
Mar 6, 2018
by
anonymous
Answer :
SCR turned off when the anode current falls below holding current.
asked
Mar 6, 2018
by
anonymous
Description : What is holding current and latching current in SCR? Draw the gate characteristics of an SCR and explain the characteristics. What are the different signals which can be used for turning on SCR by gate control? compare them.
Answer :
(i) Holding Current: Holding current is defined as the minimum anode current required to maintain conducting SCR in the on-state. (ii) Latching Current: Latching current is defined as the ... the on-state immediately after the SCR has been turned on and the gate signal has been removed.
asked
Feb 3, 2018
by
anonymous
Description : What is the use of SCR?
Answer :
SCR are use in lamp dimming, power regulators, motor control, rectifications of high power AC, control of welding machines and also use as switch these are some uses of silicon controlled rectifier.
asked
Dec 9, 2017
by
anonymous
Description : Thyristor can be protected from over voltages by using
Answer :
Thyristor can be protected from over voltages by using Voltage clamping device
asked
May 8, 2018
by
anonymous
Description : Leakage current flows through the thyristor in
Answer :
Leakage current flows through the thyristor in Forward blocking mode and Reverse blocking mode.
asked
May 8, 2018
by
anonymous
Description : What is a phase control thyristor?
asked
Mar 19, 2018
by
anonymous
Description : What is thyristor family?
asked
Mar 19, 2018
by
anonymous
Description : What is meant by firing angle of thyristor?
Answer :
The point at which SCR is triggered is known as firings angle of thyristor.
asked
Mar 19, 2018
by
anonymous
Description : What is the use of a thyristor in a circuit?
asked
Mar 19, 2018
by
anonymous
Description : What is a reverse conducting thyristor?
asked
Mar 19, 2018
by
anonymous
Description : What is the function of a thyristor?
asked
Mar 19, 2018
by
anonymous
Description : How is a thyristor used to convert AC to DC?
asked
Mar 19, 2018
by
anonymous
Description : What is the application of thyristor?
asked
Mar 19, 2018
by
anonymous
Answer :
Yes ,it is one of the main advantage using thristors as a switch in DC circuit ,it has a high current gain
asked
Mar 6, 2018
by
anonymous
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.
asked
Feb 19, 2018
by
anonymous
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
asked
Dec 6, 2017
by
anonymous
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.
asked
Nov 15, 2017
by
anonymous
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 : Why is pulse train gating preferred over pulse gating? Explain with relevant circuit and waveforms, the pulse train gating of SCRs.
asked
Mar 11, 2018
by
anonymous
Description : Purpose of Selective Catalytic Reduction (SCR)
Answer :
Purpose of Selective Catalytic Reduction (SCR) : 1. It reduces Nox 75% to 90% 2. Converts it in to molecular nitrogen and water vapor 3. It reduces HC emission up to 80% 4. It reduces PM emission 20 to 25%.
Description : An inductor is connected in series with SCR to protect it from A) Excessive high voltage B) Excessive high dv/dt C) Excessive high di/dt D) Excessive large forward current
Answer :
An inductor is connected in series with SCR to protect it from Excessive high di/dt
asked
Jun 18, 2018
by
anonymous
Description : The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a firing delay angle, α and flux, Φ (A) directly proportional to α and Φ (B) inversely proportional to α and Φ (C) directly proportional to α and inversely proportional to Φ (D) directly proportional to Φ and inversely proportional to α
Answer :
The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a firing delay angle, α and flux, Φ directly proportional to α and inversely proportional to Φ
asked
Apr 28, 2018
by
anonymous
Description : In a 3-phase converter circuit during commutation when one SCR in one phase is turned on to turn-off an SCR in another phase, results in (A) voltage notching (B) harmonic distortion (C) voltage sag (D) voltage swell
Answer :
In a 3-phase converter circuit during commutation when one SCR in one phase is turned on to turn-off an SCR in another phase, results in voltage notching
asked
Apr 28, 2018
by
anonymous
Description : How do you test an SCR?
asked
Mar 15, 2018
by
anonymous
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.
asked
May 3, 2020
by
anonymous
Answer :
By using some circuit the forward DC current of thyristor is forced to zero is called forced commutation.
asked
Sep 21, 2017
by
anonymous
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.
asked
Sep 21, 2017
by
anonymous
Answer :
No we cannot turn off normal thyristor using Gate.
asked
Sep 21, 2017
by
anonymous
Answer :
Thyristor conducts when the anode voltage is greater than cathode and when the current provided to Gate.
asked
Sep 21, 2017
by
anonymous