ELECS Flashcards
Which transistor configuration is more stable?
Voltage Divider Biased
It is where the loadline intersects with the saturation point;
saturation region
Quiescent or Q-point position is dependent on
1) load resistance
2) supply voltage
3) collector current
Which class of amplifier has the highest efficiency?
Class C
It is the material that lead to a deficiency of electrons and therefore an excess of positive charge carriers or “holes.”
P-type semiconductor
In which BJT configuration is the output signal taken between the collector and the emitter?
Common Collector
The transistor terminal that handles most current.
emitter
Which is a characteristic of Class AB amplifiers?
A) Both transistors conduct for more than 180 degrees but less than 360 degrees.
B) Only one transistor conducts for 360 degrees.
C) Both transistors conduct for exactly 180 degrees.
D) Only one transistor conducts for 360 degrees.
A) Both transistors conduct for more than 180 degrees but less than 360 degrees.
The scientists who were responsible for the 1947 invention of the transistor were:
1) Walter Brattain
2) William Shockley
3) John Bardeen
What is the primary advantage of Class D amplifiers?
High efficiency
What device employs only an electron or hole?
unipolar
Which BJT configuration provides the same polarity at both input and output terminals?
Common Collector
When the base-emitter junction is forward biased and Base-collector junction is forward biased the transistor operation is in _____.
saturation
When the transistor is heated, what will happen to the transistor?
The transistor will saturate
Which BJT configuration is often used in RF amplifier circuits due to its high input impedance and low output impedance?
Common Base
It is also called the common collector forward current amplification factor.
gamma
Which BJT configuration exhibits a voltage gain less than unity?
Emitter Follower
Which BJT configuration provides the highest input impedance?
Common Base
The electron-hole pair is produced by
Recombination
It is where the loadline intersects with the cut-off point.
cut-off region
When the value of the base current is equal to zero, what does it mean?
The collector current is approximately equal to the emitter current
It is also called the maximum possible VCE.
Cut-off voltage
Which BJT configuration offers the highest current gain?
Darlington Pair
Which BJT configuration exhibits a phase shift of 180 degrees between input and output signals?
Emitter Follower
What is the main drawback of Class C amplifiers?
Low efficiency
Which of the following statements is true about Class A amplifiers?
A) They have a high efficiency but high distortion.
B) They have a high efficiency and low distortion.
C) They have a low efficiency but low distortion
D) They have a low efficiency and high distortion
C) They have a low efficiency but low distortion
When Vce is a negative value, what does it mean?
The transistor current will be set to the maximum value
Which class of amplifier is commonly used in applications where efficiency is critical, such as in RF transmitters?
Class C
The most widely used semiconductive material in electronic devices is
Silicon
It is the intersection between the loadline and the given value of Ib
quiescent point
In which BJT configuration is the emitter current the sum of the base and collector currents?
Common Collector
A semiconductor device that Amplifies, Oscillates, or Switches the flow of current between two terminals
transistors
It is also called the maximum possible current that can be delivered by the transistor
saturation current
It is situated opposite to the emitter and always in reversed bias.
collector
It is the impurities that result in an excess of electrons, or negative charges
N-type semiconductor
In which BJT configuration is the input signal applied between the emitter and the base?
Common Base
When the base-emitter junction is forward biased and Base-collector junction is reversed biased the transistor operation is in
active
If the value of Vce is negative, what does it mean?
The transistor is saturated
Which BJT configuration offers the highest voltage gain?
Common Emitter
It describes the values of Ic and Vce across the load from the cut-off to the saturated condition.
Loadline
It is the point where the values of the collector current equal to zero.
Cut-off point
A trivalent impurity is added to silicon to create
a p-type semiconductor
Which of the following statements is true about the transistor?
A) The base terminal must not be connected to the ground
B) The base material is thicker than other terminal
C) The base material must always be P-type material
D) The base-emitter voltage is always equal to the potential barrier
D) The base-emitter voltage is always equal to the potential barrier
The barrier potential for germanium devices is
0.3 V
It is the ratio of the output current Ic to the input current IB
beta
characteristic of Class D amplifiers?
They operate as switch-mode amplifiers.
Which BJT configuration provides high input impedance and low output impedance?
Common Collector
In a Class B amplifier, each transistor conducts how much of the input cycle?
180 degrees
The collector terminal for PNP type transistor must be reversed biased
True
It is a highly doped material to inject a large number of charged carriers.
emitter
When the transistor is off, what does it mean?
The collector current is set to its minimum value
It is also called the maximum possible collector current.
saturation current
Collector-emitter resistance of ideal transistor at cut-off
infinite
Class C amplifiers are primarily used in which type of application?
RF amplification
When the base-emitter junction is reversed biased and Base-collector junction is reversed biased the transistor operation is
in ________.
cut-off
What is the main advantage of Class C amplifiers?
High efficiency
Class B amplifiers are most commonly used in which type of applications?
Audio power amplification
Which BJT configuration is commonly used as a voltage buffer?
Emitter Follower
In which BJT configuration is the input signal applied to the base and output taken from the emitter?
Common Collector
It is the ratio of the collector current to the emitter current.
alpha
It is determined by Vce and Ic.
Operating point
Class A amplifiers operate in which region of the transistor’s characteristic curve?
Active
What is the main disadvantage of Class A amplifiers?
Low efficiency
If VCE is less than or equal to zero 0V the transistor is
at saturation region
The flow of electrons in an NPN transistor when used in an electronic circuit is from
Emitter to Collector
What is true about transistor construction?
A) The base-emitter junction is thinner than the base-collector junction
B) The base-emitter junction is thicker than the base-collector junction
C) The amount of base current cannot be measured
D) Emitted is the lightly doped material
A) The base-emitter junction is thinner than the base-collector junction
It is lightly doped material so that most of the charge carriers pass to the collector.
base
The bipolar junction transistor can perform the following functions, except
a. switching device
b. diode functions
c. voltage controlled amplifier
d. current controlled amplifier
c. voltage controlled amplifier
Which BJT configuration offers the highest power gain?
Darlington Pair
In Class AB amplifiers, the biasing is set to ensure which of the following?
a. One transistor operates in the cut-off region and the other in the saturation region.
b. Both transistors operate in the saturation region.
c. Both transistors operate in active regions.
d. Both transistors operate in the cut-off region.
a. One transistor operates in the cut-off region and the other in the saturation region.
The original transistor is called
point-contact transistor
It is the locus of all possible operating points of a transistor
loadline
Class D amplifiers are also known as
Switching amplifiers
In which BJT configuration is the collector connected to the ground (or common reference)?
Common Collector
Operates as an amplifier
Active Region
“fully-ON” operates as a switch
Saturation
“fully-OFF” operating as a switch
Cut-off
has Voltage Gain but no Current Gain.
Common Base Configuration
has both Current and Voltage Gain.
Common Emitter Configuration
has Current Gain but no Voltage Gain.
Common Collector Configuration
the BASE connection is common to both the input signal AND the output signal.
Common Base
The collector current output is less than the
emitter current input
Current gain for Common Base
“1” (unity) or less
The common base configuration “_________” the input signal
attenuates
Non-inverting voltage amplifier circuit (Vin and Vout is In-phase)
Common Base
Used in single stage amplifier circuits such as microphone pre-amplifier or radio frequency ( Rƒ) amplifiers due to its very good high frequency
response
Common Base
The current flowing out of the transistor must be equal to the currents flowing into the transistor as the emitter current is given as ie = ic + ib.
Common Emitter
The current gain, ________ is quite large as it is the ratio of ic/ib
beta ( β)
has a value between 20 and 200 for most general-purpose transistors
beta ( β)
Has a greater input impedance, current and power gain than that of the common base configuration but its voltage gain is much lower.
Common Emitter
an inverting amplifier circuit, resulting output signal has a 180o phase-shift with regards to the input voltage signal
Common Emitter
collector is connected to the ground through the supply.
Common Collector
input signal is connected directly to the base terminal, while the output signal is taken from across the emitter load resistor
Common Collector
Commonly known as a voltage follower or emitter follower circuit
Common Collector
very useful for impedance-matching applications
Common Collector
Very high input impedance and relatively low output impedance
Common Collector
It has a current gain approximately equal to the β value of the transistor
Common Collector
It is a non-inverting circuit in that the signal voltages of vin and vout are “in-phase”
Common Collector
Has a voltage gain of about “1” (unity gain), it can considered as a voltagebuffer.
Common Collector
central operating point
“Quiescent Operating Point”, or Q-point for short
