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WorksheetsSemiconductor and Transistor Quiz
Total questions: 40
Worksheet time: 20mins
A semiconductor is formed by ........ bonds.
covalent
electrovalent
co-ordinate
none of the above
A semiconductor has ........ temperature coefficient of resistance.
positive
zero
negative
none of the above
The most commonly used semiconductor is ........
germanium
silicon
carbon
sulphur
Addition of pentavalent impurity to a semiconductor creates many ........
free electrons
holes
valence electrons
bound electrons
The barrier voltage at a pn junction for germanium is about ........
3.5 V
3V
zero
0.3 V
A crystal diode has ........
one pn junction
two pn junctions
three pn junctions
none of the above
If the arrow of crystal diode symbol is positive w.r.t. bar, then diode is ........ biased.
forward
reverse
either forward or reverse
none of the above
Zener diodes are used primarily as
amplifiers
voltage regulators
rectifiers
oscillators
A pn junction that radiates energy as light instead of as heat is called a
LED
photo-diode
photocell
Zener diode
A photo-diode is normally
forward-biased
reverse-biased
Neither forward nor reverse biased
Emitting light
To display the digit 0 in a seven segment display
A must be lighted
F must be off
G must be on
all segments except G should be lighted
A zener diode is always .......... connected.
reverse
forward
either reverse or forward
none of the above
A crystal diode is used as ........
an amplifier
a rectifier
an oscillator
a voltage regulator
The ripple factor of a half-wave rectifier is ........
2
1.21
2.5
0.48
The ...... filter circuit results in the best voltage regulation.
choke input
capacitor input
resistance input
none of the above
The most widely used rectifier is ...........
half-wave rectifier
centre-tap full-wave rectifier
bridge full-wave rectifier
none of the above
In the breakdown region, a zener diode behaves like a ......... source.
constant voltage
constant current
constant resistance
none of the above
When a crystal diode is used as a rectifier, the most important consideration is ........
forward characteristic
doping level
reverse characteristic
PIV rating
In the depletion region of a pn junction, there is a shortage of ..........
acceptor ions
holes and electrons
donor ions
none of the above
A reverse biased pn junction has ........
very narrow depletion layer
almost no current
very low resistance
large current flow
A pn junction acts as a ........
controlled switch
bidirectional switch
unidirectional switch
none of the above
A hole in a semiconductor is defined as ........
a free electron
the incomplete part of an electron pair bond
a free proton
a free neutron
At room temperature, an intrinsic silicon crystal acts approximately as ........
a battery
a conductor
an insulator
a piece of copper wire
What is the main function of a transistor?
Amplification
Rectification
Voltage regulation
Power generation
A transistor consists of how many semiconductor layers?
2
3
4
5
In an NPN transistor, current flows from:
Emitter to Base
Collector to Base
Base to Emitter
Collector to Emitter
In a common emitter configuration, the phase difference between input and output is:
0°
90°
180°
270°
Which transistor region is responsible for controlling the current flow?
Collector
Emitter
Base
None of these
The emitter region in a transistor is:
Lightly doped
Moderately doped
Heavily doped
Not doped
Which region of a transistor is the largest in size?
Emitter
Collector
Base
All are equal
Which transistor configuration has the highest input impedance?
Common Base
Common Collector
Common Emitter
None of these
The cut-off region of a transistor is when:
Both junctions are forward biased
Both junctions are reverse biased
One junction is forward biased, and the other is reverse biased
None of these
The base current in a transistor is:
Greater than collector current
Equal to emitter current
Less than emitter current
Equal to collector current
What is the approximate voltage drop across a silicon transistor's base-emitter junction in forward bias?
0.1V
0.3V
0.7V
1.2V
The voltage gain of a common emitter amplifier is:
Low
High
Zero
None of these
The output resistance of a common base configuration is:
Very high
Very low
Zero
Moderate
Which transistor mode is used for amplification?
Cut-off
Saturation
Active
Breakdown
Which current is the largest in a transistor?
Emitter current
Base current
Collector current
All are equal
What happens if the base current in a transistor is increased?
Collector current decreases
Collector current increases
Collector current remains the same
Transistor stops working
In the voltage divider bias method, the purpose of the divider resistors is to:
Regulate emitter current
Reduce power consumption
Maintain a stable base voltage
Control the output voltage
