Description : An SCR starts conducting with appreciable current when
Last Answer : An SCR starts conducting with appreciable current when anode and gate both are positive
Description : What is the only way to cause an SCR to stop conducting?
Last Answer : The forward bias must be reduced below the minimum conduction level.
Description : To turn a conducting SCR to off state, it is necessary to make : - a) anode current less than holding current b)gate current zero c) anode voltage less than break over voltage d) gate voltage zero
Last Answer : To turn a conducting SCR to off state, it is necessary to make : - anode current less than holding current
Description : When an SCR is forward biased, what is needed to cause it to conduct?
Last Answer : A gate signal.
Description : During forward blocking state, the SCR has:
Last Answer : During forward blocking state, the SCR has: low voltage, large current
Description : What is the relation between the gate signal and forward break over voltage (VBO)?
Last Answer : Thyristor can be triggered by increasing the forward voltage between anode and cathode, at forward break over voltage thyristor starts conducting. However this process may damage the thyristor, so thyristor ... of the gate current. Higher is the gate current lower is the forward break over voltage
Description : A silicon controlled rectifier (SCR) is a solid state device used to change ________________. A. DC to AC and control relatively low load current B. AC to DC and control relatively high load ... to AC and control relatively high load current D. AC to DC and control relatively low load current
Last Answer : Answer: B
Description : Justify. Power MOSFET is operated at high enough gate source voltage to minimize the conduction losses.
Last Answer : MOSFET is metal oxide field effect transistor. MOSFET is a voltage controlled device. MOSFET is majority carrier device. MOSFET are of two one is n-channel MOSFET and p-channel MOSFET. Gate, ... . Hence, power MOSFET is operated at high enough gate-source voltage to minimize the conduction losses.
Description : Conducting part starts with external nostrils and extended upto____
Last Answer : Conducting part starts with external nostrils and extended upto____
Description : Five coulombs of charge are placed on a thin-walled conducting shell. Once the charge has come to rest, the electric potential inside the hollow conducting shell is found to be: w) zero x) uniform ... sphere y) smaller than the electric potential outside the sphere z) varying as one over r squared.
Last Answer : ANSWER: X -- UNIFORM INSIDE THE SPHERE AND EQUAL TO THE ELECTRIC OTENT
Description : The device in figure 'B' shown in the illustration will conduct when the ____________. EL-0067 A. base-emitter is forward biased and the collector-base is reverse biased B. anode-cathode is forward ... is reversed biased D. terminal 1-2 is forward biased and the emitter-terminal 1 is reverse biased
Description : Since the characteristics of the device shown in figure 'A' of the illustration includes a stable voltage and low current while operating, it can be suitably used in _____________. EL-0065 A. oscillators ... . class A and B amplifiers C. generator rectifier and filtering supplies D. all of the above
Last Answer : Answer: A
Description : What is latching current in SCR?
Last Answer : It is the minimum current required to latch(turn on) the SCR from forward blocking state to forward conduction state.
Description : What is holding current in SCR?
Last Answer : When scr is conducting current in forward conduction state, scr will return to forward blocking state when the anode current or forward current falls below a low level called Holding current Note: ... the turn off process. In general holding current will be slightly lesser than the latching current.
Description : After firing as SCR, the gating pulse is removed. The current in the SCR will 1. remain the same 2. immediately fall to zero 3. rise up 4. None
Last Answer : After firing as SCR, the gating pulse is removed. The current in the SCR will remain the same
Description : Surge current rating of an SCR specifies the maximum (a) Repetitive current with sine wave (b) Non-repetitive current with sine wave (c) Non-repetitive current with rectangular wave (d) Repetitive current with rectangular wave
Last Answer : Surge current rating of an SCR specifies the maximum Non-repetitive current with sine wave
Description : Holding current for an SCR is best described as: (1) The minimum current required for turn-off (2) The current required before an SCR will turn on (3) The amount of current required to maintain conduction (4) The gate current required to maintain conduction
Last Answer : Holding current for an SCR is best described as: The amount of current required to maintain conduction.
Last Answer : SCR turned off when the anode current falls below holding current.
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.
Last 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.
Description : What is the difference between SCR and thyristor?
Last Answer : SCR is a type of thyristor. Like GTO, IGCT, MCT, TRIAC, DIAC etc. are the types of thyristor.
Description : The function of Snubber circuit connected across the SCR is to (A) Suppress dv/dt (B) Increase dv/dt (C) Decrease dv/dt (D) Decrease di/dt
Last Answer : The function of snubber circuit across a SCR is to Reduce dv/dt
Description : SCR can act as _______ controlled rectifier. A. phase B. frequency C. amplitude D. power
Last Answer : SCR can act as phase controlled rectifier.
Description : For an SCR with turn-on time of 5 microsecond, an ideal trigger pulse should have (a) short rise time with pulse width = 3 µsec (b) long rise time with pulse width = 6 µsec (c) short rise time with pulse width = 6 µsec (d) None of the above
Last Answer : a
Last Answer : For an SCR, di/dt protection is achieved through the use of L in series with SCR.
Description : What are the advantages of GTO over SCR?
Last Answer : a. Elimination of commutation of commutating components in forced commutation, resulting in reduction in cost, weight and volume. b. Reduction in acoustic noise and electromagnetic noise due to ... turn-off, permitting high switching frequencies. d. Improved efficiency of the converters.
Description : How GTO is advantages over SCR
Last 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.
Description : Which of the following can reduce the Eddy current losses? A) By making the core of a stack of plates electrically insulated from each other B) By making the core of solid block C) By increasing the applied voltage D) None of these
Last Answer : Which of the following can reduce the Eddy current losses? A) By making the core of a stack of plates electrically insulated from each other B) By making the core of solid block C) By increasing the applied voltage D) None of these
Description : Eddy current losses in transformer cores can be reduced by the use of 1. Solid cores 2. Laminated cores 3. Ferrites Select the correct answer using the codes given below : (a) 2 and 3 only (b). 1 and 2 only (c) 1 and 3 only (d) 1, 2 and 3
Last Answer : Eddy current losses in transformer cores can be reduced by the use of 1. Solid cores 2. Laminated cores 3. Ferrites Select the correct answer using the codes given below : (a) 2 and 3 only (b). 1 and 2 only (c) 1 and 3 only (d) 1, 2 and 3
Description : O.D.C. Stands for (a) On direct current (b) Over dimensioned consignment* (c) None of them (d) Operating & gate
Last Answer : (b) Over dimensioned consignment*
Description : How long does it take for a dog to die from chocolate poisoning once he starts showing signs?
Last Answer : Erm… I assume you’ve taken him to the vet?!?! You’re concerned about your dog dying and you’re asking strangers on the internet instead of a professional?
Description : Do you remove flower once zucchini fruit starts to grow?
Last Answer : May be too much watering. Try letting your plant dry out a bit.
Description : Why is that once a person starts taking alcohol or drugs, it is difficult to get rid of this habit? Discuss it with your teacher. -Science
Last Answer : Psychological & physiological dependence of an individual to the intake of certain kinds of drugs and alcohol is called addiction. Once a person start taking alcohol & drugs, it is very difficult to get rid ... circle leading to their regular use (abuse) from which he/she may not able to get out.
Description : What happens to the petals of the flames of the forest flower once the fruit starts to develop?
Last Answer : they will wither and fall off
Description : In an Ethernet local area network, which one of the following statements is TRUE ? a. A station stops to sense the channel once it starts transmitting a frame. b. The purpose ... collision is detected. d. The exponential backoff mechanism reduces the probability of collision on retransmissions
Last Answer : The exponential backoff mechanism reduces the probability of collision on retransmissions
Description : When the bubbles of steam are produced? • Once the water reaches saturation temperature • Once the water starts evaporating • Once the temperature decreases • None of the above
Last Answer : • Once the water reaches saturation temperature
Description : Once the logic of a network is laid out, the project manager will conduct a forward pass and a backward pass through the network. This will provide information regarding ______ and will identify ... C. Resource shortages, high risk activities D. The high risk activities, non-critical path
Last Answer : A. The total duration of the project, critical path
Description : If the addressee of ordinary article is not traceable and address of the sender is not noted on the article a) The article is kept in office undelivered b) The beat postman tries to find out ... in deposit for 7 days d) The article may be destroyed with permission of Postmaster / Sub postmaster
Last Answer : c) The deposit PA forward it RLO after passing remark in red ink after keeping in deposit for 7 days
Description : Draw the power and control circuit diagram for forward — stop — Reverse type DOL starter for 3 phase induction motor.
Last Answer : Draw the power and control circuit diagram for forward — stop — Reverse type DOL starter for 3 phase induction motor.
Description : State what is the significance of conducting phasing out test on a 3-phase transformer? Explain its procedure with a suitable connection diagram.
Last Answer : -Short primary & secondary winding of other phases expect the one under test. -Connect voltmeter to secondary winding. -A small DC current is circulated through the primary winding through ... . -The test repeated for finding out remaining concerned secondary windings in the same manner.
Description : Explain triggering of SCR using opto-coupler. State its advantages.
Last 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.
Description : Draw the circuit diagram of battery charger using SCR and explain it’s working.
Last 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.
Description : Draw construction of SCR using two transistor model. Explain its operation.
Last Answer : Two Transistor Model of SCR or Thyristor
Description : An SCR can only be turned off via it's (A) cathode (B) anode (C) gates (D) none
Last Answer : An SCR can only be turned off via it's anode
Description : Two identical conducting wires `AOB and COD` are placed at right angles to each other. The wire `AOB` carries an electric current `I_(1) and COD` carr
Last Answer : Two identical conducting wires `AOB and COD` are placed at right angles to each other. The wire `AOB` carries an electric ... )^(2)+I_(2)^(2))^(1//2)`
Description : A long conducting wire carrying a current I is bent at `120^(@) `( see figure). The magnetic field B at a point P on the right bisector of bending ang
Last Answer : A long conducting wire carrying a current I is bent at `120^(@) `( see figure). The magnetic field B at a ... (3pid))` D. `(sqrt(3mu_(0)I))/(2pid)`
Description : A non - popular loop of conducting wire carrying a current `I` is placed as shown in the figure . Each of the straighrt sections of the loop is of the
Last Answer : A non - popular loop of conducting wire carrying a current `I` is placed as shown in the figure . Each of the ... `(1)/(sqrt(2))(hat(i)+hat(k))`
Description : A conducting stick of length 2L and mass m is moving down a smooth inclined plane of inclination `60^(@)` with constant speed 5m/s. A current 2A is fl
Last Answer : A conducting stick of length 2L and mass m is moving down a smooth inclined plane of inclination `60^(@)` with ... )/(4L)` D. `(sqrt(3)mg)/(2L)`
Description : A conducting loop carrying a current `I` is placed in a uniform magnetic field ponting into the plane of the paper as shown. The loop will have a tend
Last Answer : A conducting loop carrying a current `I` is placed in a uniform magnetic field ponting into the plane of the ... +ve X-axis D. move towards -ve X-axis
Description : Assertion : If a current is flowing through a conducting wire of non-uniform cross-section, drift speed and resistance both will increase at a section
Last Answer : Assertion : If a current is flowing through a conducting wire of non-uniform cross-section, drift ... . If Assertion is false but Reason is true.