1.
A freewheeling diode in a phase-controlled rectifier
2.
How many semiconductor layers does an SCR have?
3.
The di/dt protection for an SCR is achieved through the use of
4.
The triac is equivalent to
5.
dv/dt protection is provided to the SCR by
6.
The terminals of a power MOSFET are called
7.
When the temperature increases, the intrinsic stand off ratio
8.
In a thyristor dc chopper, which type of commutation results in best performance ?
9.
A boost-regulator has an input voltage of 5V and the average output voltage of 15 V. The duty cycle is
10.
What region lies between the peak point and valley point of UJT emitter characteristic?
12.
A freewheeling diode is connected across R-L load, because
13.
The ON voltage and forward breakover of an SCR depend on the
14.
Which of the following can change the angle of conduction in SCR?
15.
When the emitter terminal of a UJT is open, the resistance between the base-terminals is generally
16.
What is an automatic speed control device using the centrifugal force on rotating flyweights as the feedback element?
17.
Which is suitable for making the variable frequency drives
18.
Why is an external pass resistor used in a voltage regulator ?
19.
Which of the following does not cause permanent damage to an SCR?
20.
Which one of the following is used as the main switching element in a switched mode power supply operating in 20 kHz to 100 kHz range?
22.
Switching regulators are also called
23.
What is the required gate triggering current of GTO?
24.
R-C snubber is used in parallel with the thyristor to
25.
Thyristor as a solid state relay is useful
26.
A single-phase half wave rectifier circuit has a freewheeling diode. The freewheeling diode will conduct only if
27.
What Greek word which means “switch”?
28.
The three terminals of an SCR are the
29.
Which of the following devices should be used as a switch in a low power switched mode power supply (SMPS) ?
30.
Which of the following devices does not belong to the transistor family?
31.
When the temperature increases, the inter-base resistance of a UJT
32.
An SCR is a solid state equivalent of which tube?
33.
The V-I characteristics for a triac in the first and third quadrants are essentially identical to those of in the quotation.
35.
For a BJT α = 0.98, then β =
36.
When the firing angle of SCR is increased, its output
37.
ECG stands for electrocardiography while EEG stands for?
38.
Which is four terminal device
39.
Power electronics deals with the control of ac power at what frequencies essentially?
40.
AC voltage regulators are widely used in
41.
Latching current of an SCR is
42.
An ideal regulated power supply should have
43.
The triac can be used only in
44.
Which terminal does not belong to the SCR?
45.
Two thyristor of same rating and same specifications
47.
With gate open, if the supply voltage exceeds the breakover voltage of SCR, then SCR will conduct
48.
The output voltage in a switching regulator for an input Vin and duty cycle δ is
49.
What is a three terminal device used to control large current to a load?
50.
In order to get best results per unit cost, the heat sinks, on which the thyristors are mounted , are made of
