1.
As compared to power MOSFET, a BJT has
2.
In a switching regulator , the control transistor is conducting
3.
The ON voltage and forward breakover of an SCR depend on the
4.
The quality of output ac voltage of a cycloconverter is improved with
5.
Which terminal does not belong to the SCR?
6.
The peak reverse blocking voltage of an IGBT is nearly
7.
A resistor connected across the gate and cathode of an SCR
8.
The terminals of a power MOSFET are called
9.
Thyristor is a semiconductor switch which is
10.
Natural commutation can be used in:
11.
Once an SCR is turned on, it remains so until the anode current goes below
12.
An SCR is made of what material?
13.
In order to get best results per unit cost, the heat sinks, on which the thyristors are mounted , are made of
14.
What is that voltage above when the SCR enters the conduction region?
15.
Why is an external pass resistor used in a voltage regulator ?
16.
In a thyristor, di/dt protection is achieved by the use of
17.
The minimum gate current which can turn on SCR is called:
19.
An RC snubber circuit is used to protect a thyristor against:
20.
The use of multiphase rectifier in place of one phase rectifier results in
21.
Thyristor is nothing but a
22.
In ac motor control, the ratio of voltage-to-frequency is maintained at constant value
24.
Which is suitable for making the variable frequency drives
25.
Two thyristor of same rating and same specifications
26.
A diac has how many semiconductor layers?
27.
Which of the following is the normal way to turn on a diac?
28.
The three terminals of a triac are
29.
Which one of the following is NOT the advantage of solid state switching of ac capacitors into ac supply over relay-based switching?
30.
Turned-off time of a thyristor
31.
Most SCRs can be turned-off by voltage reversal during negative half cycle of the ac supply for
32.
Which of the following is a four-layer diode with an anode gate and a cathode gate?
33.
A thyristor controlled reactor, the firing angle of thyristor is to be controlled in the range of
34.
An SCR combines the feature of
35.
A feedback control system in which the controlled variable is mechanical position.
36.
What is a three terminal device used to control large current to a load?
37.
Turned-on of a thyristor takes place when
38.
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?
40.
An SCR is made of silicon and not germanium because silicon.
42.
A single-phase full converter gives maximum and minimum output voltage at firing angles of
43.
The torque produced by a single-phase induction motor fed through an ac voltage controller for speed control is due to
44.
di/dt protection is provided to the thyristor by
45.
Which of the following is NOT a method primarily used for density sensing?
46.
A single-phase half wave rectifier circuit has a freewheeling diode. The freewheeling diode will conduct only if
47.
How many semiconductor layers does an SCR have?
48.
When SCR starts conducting, then ______losses all control.
49.
The main advantage of IGBT over SCR in power electronics is
50.
Turn-on and turn-off times of transistor depend on
