1.
What is an automatic speed control device using the centrifugal force on rotating flyweights as the feedback element?
2.
An SCR is considered to be a semicontrolled device because
3.
An SCR is a solid state equivalent of which tube?
4.
A freewheeling diode in a phase-controlled rectifier
5.
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
6.
Which is equivalent to a zener or avalanche region of the fundamental two-layer semiconductor diode?
7.
Which one of the following statements is correct? In the case of load regulation
8.
Which terminal does not belong to the SCR?
9.
How many pn junction does SCRs have?
10.
What Greek word which means “switch”?
11.
The ON voltage and forward breakover of an SCR depend on the
12.
With gate open, if the supply voltage exceeds the breakover voltage of SCR, then SCR will conduct
13.
The gate of an SCR is _______with respect to its cathode.
14.
A thyristor controlled reactor, the firing angle of thyristor is to be controlled in the range of
15.
How many semiconductor layers does an SCR have?
16.
Which one of the following is the most suitable device for a dc to dc converter?
17.
Which semiconductor device acts like a diode and two transistor?
18.
Turned-on of a thyristor takes place when
19.
What is a solid state equivalent of a gas filled triode?
20.
When the temperature increases, the intrinsic stand off ratio
21.
When the temperature increases, the inter-base resistance of a UJT
22.
Once an SCR is turned on, it remains so until the anode current goes below
23.
Thyristor is a semiconductor switch which is
24.
A modern power semiconductor device that combines the characteristics of BJT and MOSFET is
25.
The typical turn-off time of an SCR is about
26.
SCR turns OFF from conducting state to blocking on
27.
The SCR can exercise control over of ac supply.
28.
AC voltage regulators are widely used in
29.
When the firing angle of SCR is increased, its output
30.
Current in SCR to turn on transient can be reduced by
31.
Thyristor is nothing but a
32.
To turn on the UJT, the forward bias on emitter diode should be______ the peak point voltage.
34.
An SCR triggered by a current pulse through its gate can be turned off by
35.
Which of the following does not cause permanent damage to an SCR?
36.
Which transistor conducts current in both directions when turned on?
37.
Which one of the following is a regulated power supply?
38.
The sharing of the voltage between thyristors operating in series is influenced by their
39.
Which one of the following is the main advantage of SMPS over linear power supply ?
40.
The three terminals of an SCR are the
41.
Line regulation is determined by
42.
Control system that maintains a speed voltage, or other variable within specified limits of a preset level.
43.
The advantage of using a freewheeling diode with bridge type ac/dc converterr is
45.
In ac motor control, the ratio of voltage-to-frequency is maintained at constant value
46.
Switching regulators are also called
48.
When fed from a fully controlled rectifier, a dc motor, driving an active load can operate in
49.
What region lies between the peak point and valley point of UJT emitter characteristic?
