1.
Which of the following is NOT a method primarily used for density sensing?
2.
The terminals of a power MOSFET are called
3.
Most SCRs can be turned-off by voltage reversal during negative half cycle of the ac supply for
4.
Which one of the following statements is correct? In the case of load regulation
5.
Which of the following is the normal way to turn on a diac?
7.
The basic difference between a series regulator and a shunt regulator is
8.
The peak reverse blocking voltage of an IGBT is nearly
9.
An SCR is in conducting state, a reverse voltage is applied between anode and cathode, but it fails to turn off. what could be the reason?
10.
Line regulation is determined by
11.
When fed from a fully controlled rectifier, a dc motor, driving an active load can operate in
12.
Latching current of an SCR is
13.
An SCR is considered to be a semicontrolled device because
14.
The quality of output ac voltage of a cycloconverter is improved with
15.
In a singe-phase full-wave controlled bridge rectifier, minimum output voltage and maximum output voltage are obtained at which conduction angles?
16.
A motor armature supplied through phase controlled SCRs receives a smoother voltage shape at
17.
Which of the following is the normal way to turn on an SCR?
18.
The shunt type regulator is suitable for which of the following?
19.
Which equation defines the intrinsic stand off ratio (y) of UJTs?
20.
An SCR chopper circuit supplies power to a dc motor , what will be the nature of motor armature current?
21.
An emitter follower regulator has the following disadvantage :
22.
What is that voltage above when the SCR enters the conduction region?
23.
An RC snubber circuit is used to protect a thyristor against:
24.
Which is suitable for making the variable frequency drives
25.
R-C snubber is used in parallel with the thyristor to
26.
In the forward blocking region of a silicon controlled rectifier, the SCR is
27.
When the temperature increases, the intrinsic stand off ratio
28.
A thyristor has its gate current zero. To start conduction the forward voltage must exceed
29.
A freewheeling diode is connected across R-L load, because
30.
A diac has how many terminals?
31.
The p-type emitter of a UJT is ______doped.
33.
The three terminals of a triac are
34.
Control system that maintains a speed voltage, or other variable within specified limits of a preset level.
35.
A freewheeling diode in a phase-controlled rectifier
36.
An SCR triggered by a current pulse through its gate can be turned off by
37.
dv/dt protection is provided to the SCR by
38.
The sharing of the voltage between thyristors operating in series is influenced by their
39.
AC voltage regulators are widely used in
40.
Which one of the following is the main advantage of SMPS over linear power supply ?
41.
How many semiconductor layers does a triac have?
42.
What is the control element in an SCR?
43.
Why is an external pass resistor used in a voltage regulator ?
46.
Turned-on of a thyristor takes place when
47.
What is dimensionless parameter of the second-order characteristic equation?
48.
What are some areas where GTO is applicable?
49.
When the firing angle of SCR is increased, its output
50.
Commutation overlap in the phase-controlled ac to dc converter is due to
