1.
The p-type emitter of a UJT is ______doped.
2.
When the SCR is OFF, the current in the circuit is
3.
In a single-phase full wave regulator, the firing angles in the positive and negative half cycles are generally.
4.
What is basically a two-terminal parallel-inverse combination of semiconductor layers that permits triggering in either direction?
5.
A thyristors are not made using germanium, because
6.
What is an automatic speed control device using the centrifugal force on rotating flyweights as the feedback element?
7.
The shunt type regulator is suitable for which of the following?
8.
Which is suitable for making the variable frequency drives
9.
Which one of the following is the most suitable device for a dc to dc converter?
10.
Two thyristor of same rating and same specifications
11.
What is dimensionless parameter of the second-order characteristic equation?
12.
The main advantage of IGBT over SCR in power electronics is
13.
Consider the following semiconductor devices:
1. Triac 2. Thyristor 3. amplifying gate thyristor
The correct sequence of these devices in increasing order of their di/dt capabilities is
14.
What is that value of current below which the SCR switches from the conduction state to the forward blocking region under stated conditions?
15.
A power supply has full-load voltage of 24V. What is its no-load voltage for 5% regulation (rounded to the nearest integer) ?
16.
Power electronics deals with the control of ac power at what frequencies essentially?
17.
A thyristor controlled reactor, the firing angle of thyristor is to be controlled in the range of
18.
The output voltage in a switching regulator for an input Vin and duty cycle δ is
19.
Triacs can not be used in ac voltage regulator for a
20.
What is a solid state equivalent of a gas filled triode?
21.
Which of the following does not cause permanent damage to an SCR?
22.
When cathode of a thyristor is made more positive than its anode
23.
The typical turn-off time of an SCR is about
24.
In a singe-phase full-wave controlled bridge rectifier, minimum output voltage and maximum output voltage are obtained at which conduction angles?
25.
Carrier frequency gate drive is used for turn-on of a thyristor to reduce.
26.
The supply voltage is generally _____that of breakover voltage in an SCR.
27.
A feedback control system in which the controlled variable is mechanical position.
28.
An ideal regulated power supply should have
29.
It is preferable to use a train of pulse of high frequency for gate triggering of SCR in order to reduce
30.
Which device does not have a gate terminal?
31.
Which is the control element in an SCR?
32.
The use of multiphase rectifier in place of one phase rectifier results in
33.
A triac can pass a portion of half cycle through the load
34.
The di/dt protection for an SCR is achieved through the use of
35.
In an LC series circuit connected to a dc supply of E volts via a thyristor when it turns off, the voltage that appears across the thyristor is
36.
The triac is equivalent to
37.
Commutation overlap in the phase-controlled ac to dc converter is due to
38.
Switching regulators are also called
39.
SCR turns OFF from conducting state to blocking on
40.
An SCR chopper circuit supplies power to a dc motor , what will be the nature of motor armature current?
41.
Turn-off time of a thyristor
42.
As compared to power MOSFET, a BJT has
43.
The V-I characteristics for a triac in the first and third quadrants are essentially identical to those of in the quotation.
45.
Line regulation is determined by
46.
What is the control element in an SCR?
47.
In a feedback series regulator circuit, the output voltage is regulated by controlling the
48.
The basic difference between a series regulator and a shunt regulator is
49.
With gate open, if the supply voltage exceeds the breakover voltage of SCR, then SCR will conduct
50.
The terminals of a power MOSFET are called
