1.
In a UPS, the solid state switch normally transfer supply within
2.
As compared to power MOSFET, a BJT has
3.
dv/dt protection is provided to the SCR by
4.
Turn-off time of a thyristor
5.
Which of the following configurations is used for both motoring and regenerative braking?
6.
A normally operated SCR has an anode which is _____ with respect to cathode.
8.
Acceleration transducers are also called
9.
A thyristor can be termed as
10.
Which one of the following controls reduces the size of the transformer in a switch mode ac power supply ?
11.
In a single-phase semiconverter with resistive load and for a firing angle α , each SCR conduction and freewheeling action takes place
12.
When the SCR is OFF, the current in the circuit is
13.
What region lies between the peak point and valley point of UJT emitter characteristic?
14.
Why is an external pass resistor used in a voltage regulator ?
15.
Thyristor is nothing but a
16.
A boost-regulator has an input voltage of 5V and the average output voltage of 15 V. The duty cycle is
18.
Which of the following is a common application of UJT?
19.
An RC snubber circuit is used to protect a thyristor against:
20.
The output voltage in a switching regulator for an input Vin and duty cycle δ is
21.
Control system that maintains a speed voltage, or other variable within specified limits of a preset level.
22.
When SCR starts conducting, then ______losses all control.
23.
The advantage of using a freewheeling diode with bridge type ac/dc converterr is
24.
SCR is a rectifier constructed of silicon material. Silicon is chosen because
25.
Turned-on of a thyristor takes place when
26.
Conductivity modulation is phenomenon which occurs in
27.
What is the required gate triggering current of GTO?
28.
Line regulation is determined by
29.
Power electronics deals with the control of ac power at what frequencies essentially?
30.
The typical turn-off time of an SCR is about
31.
A triac is equivalent to two SCRs
32.
The sharing of the voltage between thyristors operating in series is influenced by their
33.
The input power factor of the converter is
34.
ECG stands for electrocardiography while EEG stands for?
37.
The specified maximum junction temperature of thyristors is about
38.
An SCR combines the feature of
39.
For an SCR, dv/dt protection is achieved through the use of
40.
How many pn junction does SCRs have?
41.
What is an automatic speed control device using the centrifugal force on rotating flyweights as the feedback element?
42.
What Greek word which means “switch”?
43.
Static voltage equalization in series connected SCRs is obtained by the use of
44.
In a 3 phase fully controlled converter the firing frequency is
45.
When the emitter terminal of a UJT is open, the resistance between the base-terminals is generally
46.
A resistor connected across the gate and cathode of an SCR
47.
Which of the following does not cause permanent damage to an SCR?
48.
Commutation overlap in the phase-controlled ac to dc converter is due to
49.
In ac motor control, the ratio of voltage-to-frequency is maintained at constant value
50.
The triac can be used only in
