1.
A motor armature supplied through phase controlled SCRs receives a smoother voltage shape at
2.
The advantage of using a freewheeling diode with bridge type ac/dc converterr is
3.
It is preferable to use a train of pulse of high frequency for gate triggering of SCR in order to reduce
4.
What region lies between the peak point and valley point of UJT emitter characteristic?
6.
Which one of the following statements is correct? In the case of load regulation
7.
A modern power semiconductor device that combines the characteristics of BJT and MOSFET is
8.
The p-type emitter of a UJT is ______doped.
10.
Once an SCR is turned on, it remains so until the anode current goes below
12.
Which transistor conducts current in both directions when turned on?
13.
Which terminal does not belong to the SCR?
14.
A freewheeling diode in a phase-controlled rectifier
15.
Which one of the following is a regulated power supply?
17.
The di/dt protection for an SCR is achieved through the use of
18.
Acceleration transducers are also called
19.
An SCR triggered by a current pulse through its gate can be turned off by
20.
When cathode of a thyristor is made more positive than its anode
21.
With gate open, if the supply voltage exceeds the breakover voltage of SCR, then SCR will conduct
22.
Why is an external pass resistor used in a voltage regulator ?
23.
When UJTs is turned on, the resistance between emitter terminal and lower base terminal
24.
An SCR chopper circuit supplies power to a dc motor , what will be the nature of motor armature current?
25.
Which semiconductor power device, out of the following, is not a current triggered device?
26.
In a UPS, the solid state switch normally transfer supply within
27.
The specified maximum junction temperature of thyristors is about
28.
In order to get best results per unit cost, the heat sinks, on which the thyristors are mounted , are made of
29.
What is dimensionless parameter of the second-order characteristic equation?
30.
Which of the following is NOT a method primarily used for density sensing?
31.
Carrier frequency gate drive is used for turn-on of a thyristor to reduce.
32.
Two thyristor of same rating and same specifications
33.
The sharing of the voltage between thyristors operating in series is influenced by their
34.
To turn off the SCR, which of the following is done?
35.
Dc to dc converter or chopper can
36.
A freewheeling diode is connected across R-L load, because
37.
An SCR is considered to be a semicontrolled device because
38.
When the SCR is OFF, the current in the circuit is
40.
An RC snubber circuit is used to protect a thyristor against:
41.
In a single-phase semiconverter with resistive load and for a firing angle α , each SCR conduction and freewheeling action takes place
42.
A thyristor has its gate current zero. To start conduction the forward voltage must exceed
43.
The triac is fundamentally a/an_____with a gate terminal for controlling the turn-on conditions of the bilateral device in either direction.
44.
The torque produced by a single-phase induction motor fed through an ac voltage controller for speed control is due to
45.
di/dt protection is provided to the thyristor by
46.
AC power in a load can be controlled by connecting
47.
Conductivity modulation is phenomenon which occurs in
48.
Which one of the following is the most suitable device for a dc to dc converter?
49.
Turn-on and turn-off times of transistor depend on
50.
The value of anode current required to maintain the conduction of an SCR even though the gate signal is removed is called as the
