1.
When UJTs is turned on, the resistance between emitter terminal and lower base terminal
2.
The voltage across an SCR when it is turned on is about
3.
Which of the following is NOT a method primarily used for density sensing?
5.
The triac is fundamentally a/an_____with a gate terminal for controlling the turn-on conditions of the bilateral device in either direction.
6.
When an SCR is combined to a switch, it is considered as a switch.
7.
When fed from a fully controlled rectifier, a dc motor, driving an active load can operate in
8.
How many semiconductor layers does a triac have?
9.
Which one of the following is the main advantage of SMPS over linear power supply ?
10.
A transduction principle used primarily in optical sensors.
12.
Thyristor is a semiconductor switch which is
13.
In the forward blocking region of a silicon controlled rectifier, the SCR is
14.
Which transistor conducts current in both directions when turned on?
15.
An SCR triggered by a current pulse through its gate can be turned off by
16.
The p-type emitter of a UJT is ______doped.
17.
A boost-regulator has an input voltage of 5V and the average output voltage of 15 V. The duty cycle is
18.
The main advantage of IGBT over SCR in power electronics is
19.
Once an SCR is turned on, it remains so until the anode current goes below
20.
When cathode of a thyristor is made more positive than its anode
21.
How many pn junction does SCRs have?
22.
The basic difference between a series regulator and a shunt regulator is
23.
Which is suitable for making the variable frequency drives
24.
Turn-on and turn-off times of transistor depend on
27.
Acceleration transducers are also called
29.
For an SCR, dv/dt protection is achieved through the use of
30.
The snubber circuit is used in thyristor circuits for
31.
Static voltage equalization in series connected SCRs is obtained by the use of
32.
As compared to power MOSFET, a BJT has
33.
The input power factor of the converter is
34.
The value of anode current required to maintain the conduction of an SCR even though the gate signal is removed is called as the
35.
Which one of the following controls reduces the size of the transformer in a switch mode ac power supply ?
36.
Commutation overlap in the phase-controlled ac to dc converter is due to
37.
AC power in a load can be controlled by connecting
38.
What is the sensing element of acceleration transducer?
39.
What is the control element in an SCR?
40.
The triac is equivalent to
41.
When the emitter terminal of a UJT is open, the resistance between the base-terminals is generally
42.
The gate of an SCR is _______with respect to its cathode.
43.
Which of the following devices should be used as a switch in a low power switched mode power supply (SMPS) ?
44.
The SCR can exercise control over of ac supply.
45.
The typical turn-off time of an SCR is about
46.
The sharing of the voltage between thyristors operating in series is influenced by their
47.
A diac has how many terminals?
48.
When the temperature increases, the intrinsic stand off ratio
49.
With gate open, if the supply voltage exceeds the breakover voltage of SCR, then SCR will conduct
50.
In a UPS, the solid state switch normally transfer supply within
