2.
With gate open, if the supply voltage exceeds the breakover voltage of SCR, then SCR will conduct
4.
For an SCR, dv/dt protection is achieved through the use of
5.
Which equation defines the intrinsic stand off ratio (y) of UJTs?
6.
Control system that maintains a speed voltage, or other variable within specified limits of a preset level.
7.
Thyristor as a solid state relay is useful
8.
Acceleration transducers are also called
9.
The di/dt protection for an SCR is achieved through the use of
10.
Which is equivalent to a zener or avalanche region of the fundamental two-layer semiconductor diode?
11.
In a chopper fed dc drive , the chopping frequency is approximately equal to
12.
The latching current is _________ than the holding current
13.
Which of the following is the normal way to turn on an SCR?
14.
A diac has how many terminals?
15.
In a 3 phase fully controlled converter the firing frequency is
17.
Static voltage equalization in series connected SCRs is obtained by the use of
18.
Which device exhibits negative resistance region?
19.
A freewheeling diode is connected across R-L load, because
20.
The SCR can exercise control over of ac supply.
21.
Two thyristor of same rating and same specifications
22.
In ac motor control, the ratio of voltage-to-frequency is maintained at constant value
23.
A diac has how many semiconductor layers?
24.
An SCR combines the feature of
25.
Turned-off time of a thyristor
26.
Latching current of an SCR is
27.
Thyristor is a semiconductor switch which is
28.
Which one of the following is the main advantage of SMPS over linear power supply ?
30.
What is a solid state equivalent of a gas filled triode?
31.
A motor armature supplied through phase controlled SCRs receives a smoother voltage shape at
32.
In order to get best results per unit cost, the heat sinks, on which the thyristors are mounted , are made of
33.
A single-phase half wave rectifier circuit has a freewheeling diode. The freewheeling diode will conduct only if
34.
SCR is a rectifier constructed of silicon material. Silicon is chosen because
35.
The device commonly used for triggering a triac is
36.
The ON voltage and forward breakover of an SCR depend on the
37.
The snubber circuit is used in thyristor circuits for
38.
The typical turn-off time of an SCR is about
39.
Which one of the following statements is correct? In the case of load regulation
40.
An SCR triggered by a current pulse through its gate can be turned off by
41.
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?
42.
In a switching regulator , the control transistor is conducting
43.
The basic difference between a series regulator and a shunt regulator is
44.
Which of the following is a four-layer diode with an anode gate and a cathode gate?
45.
Which of the following configurations is used for both motoring and regenerative braking?
46.
Why is an external pass resistor used in a voltage regulator ?
47.
In a single-phase full wave regulator, the firing angles in the positive and negative half cycles are generally.
48.
An SCR is considered to be a semicontrolled device because
49.
When the temperature increases, the inter-base resistance of a UJT
50.
Which terminal does not belong to the SCR?
