1.
In ac motor control, the ratio of voltage-to-frequency is maintained at constant value
2.
dv/dt protection is provided to the SCR by
3.
In order to get best results per unit cost, the heat sinks, on which the thyristors are mounted , are made of
4.
The output voltage in a switching regulator for an input Vin and duty cycle δ is
5.
An ideal regulated power supply should have
6.
The terminals of a power MOSFET are called
7.
The ON voltage and forward breakover of an SCR depend on the
8.
In a thyristor dc chopper, which type of commutation results in best performance ?
9.
What is that voltage above when the SCR enters the conduction region?
10.
Thyristor is a semiconductor switch which is
11.
The gate of an SCR is _______with respect to its cathode.
12.
When cathode of a thyristor is made more positive than its anode
13.
In a singe-phase full-wave controlled bridge rectifier, minimum output voltage and maximum output voltage are obtained at which conduction angles?
15.
The torque produced by a single-phase induction motor fed through an ac voltage controller for speed control is due to
16.
With gate open, if the supply voltage exceeds the breakover voltage of SCR, then SCR will conduct
17.
A transduction principle used primarily in optical sensors.
18.
Current in SCR to turn on transient can be reduced by
19.
The voltage across an SCR when it is turned on is about
20.
The di/dt protection for an SCR is achieved through the use of
21.
Which one of the following is the main advantage of SMPS over linear power supply ?
22.
Line regulation is determined by
23.
A freewheeling diode in a phase-controlled rectifier
24.
The minimum gate current which can turn on SCR is called:
25.
Conductivity modulation is phenomenon which occurs in
27.
ECG stands for electrocardiography while EEG stands for?
28.
The triac can be used only in
29.
Latching current of an SCR is
30.
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
31.
What is a solid state equivalent of a gas filled triode?
32.
In the forward blocking region of a silicon controlled rectifier, the SCR is
33.
The triac is fundamentally a/an_____with a gate terminal for controlling the turn-on conditions of the bilateral device in either direction.
34.
AC power in a load can be controlled by connecting
35.
How many semiconductor layers does a triac have?
36.
When an SCR is combined to a switch, it is considered as a switch.
37.
Which one of the following is the most suitable device for a dc to dc converter?
38.
What is basically a two-terminal parallel-inverse combination of semiconductor layers that permits triggering in either direction?
39.
In a UPS, the solid state switch normally transfer supply within
40.
An SCR is made of silicon and not germanium because silicon.
41.
What is the sensing element of acceleration transducer?
42.
A thyristors are not made using germanium, because
43.
Which is equivalent to a zener or avalanche region of the fundamental two-layer semiconductor diode?
44.
The shunt type regulator is suitable for which of the following?
45.
The typical turn-off time of an SCR is about
46.
Switching regulators are also called
47.
The latching current is _________ than the holding current
48.
It is preferable to use a train of pulse of high frequency for gate triggering of SCR in order to reduce
49.
In a self-controlled synchronous motor fed from a variable frequency inverter
50.
An SCR chopper circuit supplies power to a dc motor , what will be the nature of motor armature current?
