1.
When UJTs is turned on, the resistance between emitter terminal and lower base terminal
2.
What region lies between the peak point and valley point of UJT emitter characteristic?
3.
Which one of the following is the main advantage of SMPS over linear power supply ?
4.
Which of the following devices should be used as a switch in a low power switched mode power supply (SMPS) ?
5.
In a UPS, the solid state switch normally transfer supply within
6.
Which one of the following is the most suitable device for a dc to dc converter?
7.
Control system that maintains a speed voltage, or other variable within specified limits of a preset level.
8.
In a chopper fed dc drive , the chopping frequency is approximately equal to
9.
The quality of output ac voltage of a cycloconverter is improved with
10.
Which is the control element in an SCR?
11.
Which one of the following statements is correct? In the case of load regulation
13.
Conductivity modulation is phenomenon which occurs in
15.
Natural commutation can be used in:
16.
The peak reverse blocking voltage of an IGBT is nearly
17.
Current in SCR to turn on transient can be reduced by
18.
What is a solid state equivalent of a gas filled triode?
19.
1. An SCR whose state is controlled by the light falling upon a silicon semiconductor layer of the device.
20.
Turn-off time of a thyristor
21.
An SCR is considered to be a semicontrolled device because
22.
For an SCR, dv/dt protection is achieved through the use of
23.
A triac is equivalent to two SCRs
24.
Which is equivalent to a zener or avalanche region of the fundamental two-layer semiconductor diode?
25.
Most SCRs can be turned-off by voltage reversal during negative half cycle of the ac supply for
26.
A modern power semiconductor device that combines the characteristics of BJT and MOSFET is
27.
The terminals of a power MOSFET are called
28.
Which device exhibits negative resistance region?
29.
Acceleration transducers are also called
30.
When fed from a fully controlled rectifier, a dc motor, driving an active load can operate in
31.
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
32.
Which of the following can change the angle of conduction in SCR?
33.
The advantage of using a freewheeling diode with bridge type ac/dc converterr is
34.
When an SCR is combined to a switch, it is considered as a switch.
35.
Which one of the following controls reduces the size of the transformer in a switch mode ac power supply ?
37.
Which of the following is the normal way to turn on a diac?
38.
An SCR is a member of what family?
39.
Carrier frequency gate drive is used for turn-on of a thyristor to reduce.
40.
The ON voltage and forward breakover of an SCR depend on the
41.
It is preferable to use a train of pulse of high frequency for gate triggering of SCR in order to reduce
42.
When the temperature increases, the intrinsic stand off ratio
43.
An SCR is made of what material?
44.
Which device does not have a gate terminal?
45.
The gate of an SCR is _______with respect to its cathode.
46.
Which is suitable for making the variable frequency drives
47.
The three terminals of a triac are
49.
AC power in a load can be controlled by connecting
