WorksheetsPower Electronics 2
Total questions: 68
Worksheet time: 33mins
A thyristor (SCR) is a
P-N-P device
N-P-N device
P-N-P-N device
P-N device
Which terminal does not belong to the SCR?
Anode
Gate
Base
Cathode
An SCR is a
four layer, four junction device
four layer, three junction device
four layer, two junction device
three layer, single junction device
In the SCR structure the gate terminal is located
near the anode terminal
near the cathode terminal
in between the anode & cathode terminal
none of the mentioned
The static V-I curve for the SCR is plotted for
Ia (anode current) vs Ig (gate current), Va (anode – cathode voltage) as a parameter
Ia vs Va with Ig as a parameter
Va vs Ig with Ia as a parameter
Ig vs Vg with Ia as a parameter
For an SCR in the reverse blocking mode, (practically)
leakage current does not flow
leakage current flows from anode to cathode
leakage current flows from cathode to anode
leakage current flows from gate to anode
With the anode positive with respect to the cathode & the gate circuit open, the SCR is said to be in the
reverse blocking mode
reverse conduction mode
forward blocking mode
forward conduction mode
In normal operation of an SCR, gate is ………..w.r.t. cathode
Positive
Negative
At zero potential
None of the above
The normal way to turn on a SCR is by ……………..
exceeding Breakover voltage
Appropriate anode current
Appropriate gate current
None of the above
An SCR is a .....switch
Unidirectional
Bidirectional
THree directional
None of the above
What will happen, if we connect capacitor to DC Supply.
It allows DC
It blocks DC
t rectifies
None of these
Hint: Diode is unidirectional and uncontrolled device. In rectifier circuit, diode use as a switch to convert ac to dc for rectification purpose.
halfwave rectified
fullwave rectified
sine wave
light bulb
The number of diodes used to build a bridge rectifier
1
2
3
4
Efficiency of a centre tapped full wave rectifier is _________
a) 50%
b) 46%
c) 70%
d) 81.2%
50%
46%
70%
81.2%
The basic purpose of a filter is to
Minimize variations in a.c. input signal.
Suppress harmonics in rectified output.
Remove ripples from the rectified output
Stabilize d.c. output voltage
What is the output of an inverter?
DC
AC
What are the good candidates for switches in dc to ac conversion techniques?
Diode
SCR
MOSFET
BJT
Why output of an inverter is not sinusoid?
Because the frequency not same
Voltage higher than input
Because rich of harmonics component
What are the techniques to control the output voltage?
PWM
buck converter
dc chopper
What analysis that can be used to represent the periodic waveform?
Trigonometry analysis
Fourier analysis
Laplace transform
Why we have to do the Fourier analysis?
To find total harmonic distortion
To find output current
To find rms output voltage
What is the fundamental value?
The sine wave that has same frequency value with the original value
The sine wave that has odd order frequency value with the original value
The sine wave that has even order frequency value with the original value
Is the section used to eliminate the AC components after the rectification.
circuit of filter
Rectifier
Regulation circuit
The electronic component used in the process of rectification is...
Capacitor
Diode
Transistor
What are the 3 legs of a transistor called?
Base, Electrode, Commiter
Bridge, Collector, Extruder
Base, Collector, Emitter
Brake, Collection, Emit
In a NPN Transistor, the current carriers are ………….
Acceptor Ions
Donor Ions
Free Electrons
Holes
In which region, the transistor operates.....?
Saturation Region
Cut-off Region
Active Region
None of the above
Which terminal was heavily dopped....?
Emitter
Base
Collector
None of the above
A transistor is a …………… operated device
Voltage
Both Voltage and Current
Current
None of the Above
At the Base-Emitter Junctions of a transistor, one finds ……………
A Reverse Bias
Low Resistance
A Wide Depletion Layer
None of the Above
In a Transistor ………………..
IE = IC + IB
IC = IE + IB
IE = IC – IB
IB = IC + IE
The input and output signals of a common emitter
amplifier are
in phase
90 degree out of phase
180 degree out of phase
270 degree out of phase
If the transistor operates such that it is either in the saturation or cut-off region, it is operating as
a filter
a switch
a signal amplifier
an emitter follower
One function of the transistor is to_____________?
rectify
amplify
limit
control
What is the type of the transistor shown?
PNP
NPN
BJT
Which statement about a transistor is correct?
Has two electrodes
Acts as a full wave rectifier
Has its own internal energy supply
Functions as an amplifier
A transistor is essentially what?
An output device
An electronic switch
A deivce that limits the flow of power
C-B Reverse Bias
C-B Reverse Bias
C-B Forward Bias
C-E Forward Bias
The purpose of biasing is to establish a ______
amplification
power source
load line
Q-point
The output impedance of a BJT transistor amplifier is __________ in nature.
resistive
capacitive
inductive
wireless
An electronic circuit having the capability to amplify power, voltage or current
transformer
attenuator
amplifier
transistor
In which region, the transistor operates.....?
Saturation Region
Cut-off Region
Active Region
None of the above
What are the names of the terminals X, Y and Z?
X = Base, Y = Collector, Z = Emitter
X = Emitter, Y = Base, Z = Collector
X = Collector, Y = Base, Z = Emitter
X = Collector, Y = Emitter, Z = Base
One function of the transistor is to_____________?
rectify
amplify
limit
control
A transistor is essentially what?
An output device
An electronic switch
A deivce that limits the flow of power
A transistor is a …………… operated device
Voltage
Both Voltage and Current
Current
None of the Above
What is the type of the transistor shown?
PNP
NPN
BJT
Which statement about a transistor is correct?
Has two electrodes
Acts as a full wave rectifier
Has its own internal energy supply
Functions as an amplifier
What is emitter current Ie of transistor that its Ic=100mA and Ib=100uA?
100.1 mA
1000mA
100 mA
Which one of the following amplifier circuits provides a phase inversion between the input and output signal?
Common Base
Common source
Common collector
Common emitter
The input and output signals of a common emitter
amplifier are
in phase
90 degree out of phase
180 degree out of phase
270 degree out of phase
If the transistor operates such that it is either in the saturation or cut-off region, it is operating as
a filter
a switch
a signal amplifier
an emitter follower
A transistor is a …………… operated device
Voltage
Both Voltage and Current
Current
None of the Above
1. An ideal power diode must have
low forward current carrying capacity
large reverse breakdown voltage
high ohmic junction resistance
high reverse recovery time
3. Power diode is __________
a three terminal semiconductor device
a two terminal semiconductor device
a four terminal semiconductor device
a three terminal analog device
4. The V-I Characteristics of the diode lie in the
1st & 2nd quadrant
1st & 3rd quadrant
1st & 4th quadrant
Only in the 1st quadrant
5. Which of the following is true in case of a power diode with R load?
I grows almost linearly with V
I decays almost linearly with V
I is independent of V
I initial grows than decays
6. A diode is said to be reversed biased when the
cathode is positive with respect to the anode
anode is positive with respect to the cathode
cathode is negative with respect to the anode
both cathode & anode are negative
7. A diode is said to be forward biased when the
cathode is positive with respect to the anode
anode is positive with respect to the cathode
anode is negative with respect to the anode
both cathode & anode are positive
Which of the following diodes uses a metal-semiconductor junction?
General purpose diodes
Fast recovery diodes
Schottky diode
None of the mentioned
Which of the below mentioned statements is false regarding Schottky diodes?
Schottky diodes have a Al-Silicon junction
There is no storage of charges in a Schottky diode
The majority charge carriers in a Schottky diode are holes
Schottky diodes can be switched off faster than a p-n junction diode of the same rating
A Schottky diode _____
has current flow due to holes only
has no reverse recovery time
has large amount of storage charges
has zero cut-in voltage
