1.
Consider the following statements:
A four-layer PNPN device having two gate leads can be turned on by applying a
1. positive current pulse to the cathode gate
2. positive current pulse to the anode gate
3. negative current pulse to the anode gate
4. negative current pulse to tha cathode gate
which of these statement is /are correct
2.
With gate open, if the supply voltage exceeds the breakover voltage of SCR, then SCR will conduct
3.
For an SCR, dv/dt protection is achieved through the use of
4.
The triac is fundamentally a/an_____with a gate terminal for controlling the turn-on conditions of the bilateral device in either direction.
5.
In a self-controlled synchronous motor fed from a variable frequency inverter
6.
Which of the following is a four-layer diode with an anode gate and a cathode gate?
7.
Consider the following semiconductor devices:
1. Triac 2. Thyristor 3. amplifying gate thyristor
The correct sequence of these devices in increasing order of their di/dt capabilities is
8.
When fed from a fully controlled rectifier, a dc motor, driving an active load can operate in
9.
A single-phase half wave rectifier circuit has a freewheeling diode. The freewheeling diode will conduct only if
10.
Acceleration transducers are also called
11.
A feedback control system in which the controlled variable is mechanical position.
12.
What is the required gate triggering current of GTO?
13.
When the temperature increases, the inter-base resistance of a UJT
14.
Freewheeling diode at the output of a rectifier allows
16.
An advantage of cycloconverter is
17.
Which of the following does not cause permanent damage to an SCR?
18.
Commutation overlap in the phase-controlled ac to dc converter is due to
19.
It is preferable to use a train of pulse of high frequency for gate triggering of SCR in order to reduce
20.
The di/dt protection for an SCR is achieved through the use of
21.
Natural commutation can be used in:
22.
Which semiconductor power device, out of the following, is not a current triggered device?
23.
Triacs can not be used in ac voltage regulator for a
25.
When SCR starts conducting, then ______losses all control.
26.
The peak reverse blocking voltage of an IGBT is nearly
27.
A thyristors are not made using germanium, because
29.
Most SCRs can be turned-off by voltage reversal during negative half cycle of the ac supply for
30.
Which one of the following is the main advantage of SMPS over linear power supply ?
31.
Current in SCR to turn on transient can be reduced by
32.
When the emitter terminal of a UJT is open, the resistance between the base-terminals is generally
33.
What is a solid state equivalent of a gas filled triode?
34.
In the SCR structure the gate terminal is located
35.
The V-I characteristics for a triac in the first and third quadrants are essentially identical to those of in the quotation.
36.
Carrier frequency gate drive is used for turn-on of a thyristor to reduce.
37.
In a UPS, the solid state switch normally transfer supply within
38.
What is dimensionless parameter of the second-order characteristic equation?
40.
Which of the following devices does not belong to the transistor family?
41.
A transduction principle used primarily in optical sensors.
42.
An SCR combines the feature of
43.
The sharing of the voltage between thyristors operating in series is influenced by their
44.
Which of the following devices should be used as a switch in a low power switched mode power supply (SMPS) ?
45.
In a single-phase semiconverter with resistive load and for a firing angle α , each SCR conduction and freewheeling action takes place
46.
Which is the control element in an SCR?
48.
What region lies between the peak point and valley point of UJT emitter characteristic?
49.
The snubber circuit is used in thyristor circuits for
50.
An SCR triggered by a current pulse through its gate can be turned off by
