108+ BJT Construction And Symbols GATE, Quiz, MCQs With Explanations

What is the most common type of BJT?

a) PNP
b) NPN
c) JFET
d) MOSFET
Answer: (b) NPN. This is because NPN BJTs are more efficient and have higher current gain.

Which region of a BJT has a thin base and is lightly doped?

a) Emitter
b) Collector
c) Base
d) Substrate
Answer: (c) Base. The base region is lightly doped and very thin, which allows it to be easily controlled by the input current.

Which of the following is not a symbol for a BJT?

a) NPN
b) PNP
c) FET
d) All of the above
Answer: (c) FET. FET (field-effect transistor) is a different type of transistor that has a different symbol.

What is the typical voltage drop across the base-emitter junction in a forward-biased BJT?

a) 0.3V
b) 0.7V
c) 1.0V
d) 1.5V
Answer: (b) 0.7V. The base-emitter junction of a forward-biased BJT typically has a voltage drop of around 0.7V.

Which of the following is true for a BJT in saturation mode?

a) The collector-base junction is reverse-biased
b) The emitter-base junction is reverse-biased
c) The collector-base junction is forward-biased
d) The emitter-base junction is forward-biased
Answer: (c) The collector-base junction is forward-biased in saturation mode. This allows for maximum current flow through the transistor.

What is the purpose of the collector in a BJT?

a) To control the base current
b) To provide a low-impedance path for the output current
c) To provide a high-impedance path for the input current
d) To create a potential difference between the emitter and base
Answer: (b) To provide a low-impedance path for the output current. The collector is designed to collect the majority of carriers from the base and provide a low-impedance path for the output current.

Which of the following is not a characteristic of a BJT?

a) High input impedance
b) Low output impedance
c) High current gain
d) High voltage gain
Answer: (a) High input impedance. BJTs have low input impedance due to their heavily doped emitter region.

What is the primary function of the base region in a BJT?

a) To control the output current
b) To provide a low-impedance path for the input current
c) To create a potential difference between the emitter and collector
d) To control the output voltage
Answer: (a) To control the output current. The base current controls the amount of collector current that flows through the transistor.

What is the doping concentration of the base region in a BJT?

a) Heavily doped
b) Moderately doped
c) Lightly doped
d) Undoped
Answer: (c) Lightly doped. The base region of a BJT is lightly doped to allow for easy control of the transistor.

Which of the following is true for a BJT in cut-off mode?

a) The collector-base junction is reverse-biased
b) The emitter-base junction is reverse-biased
c) The collector-base junction is forward-biased
d) The emitter-base junction is forward-biased
Answer: (a) The collector-base junction is reverse-biased in cut-off mode. This prevents any current from flowing through the transistor.

What is the primary advantage of a BJT over a FET?

a) Higher voltage gain
b) Higher current gain
c) Higher input impedance
d) Higher output impedance
Answer: (b) Higher current gain. BJTs have a much higher current gain than FETs, which makes them useful for amplifying signals.

Which of the following is not a disadvantage of a BJT?

a) Low input impedance
b) High power consumption
c) Limited operating temperature range
d) Low-frequency response
Answer: (d) Low-frequency response. BJTs have good frequency responses and are commonly used in high-frequency circuits.

Which of the following is true for a BJT in active mode?

a) The collector-base junction is reverse-biased
b) The emitter-base junction is reverse-biased
c) The collector-base junction is forward-biased
d) The emitter-base junction is forward-biased
Answer: (d) The emitter-base junction is forward-biased and the collector-base junction is reverse-biased in active mode. This allows for current flow through the transistor.

What is the maximum current gain for a BJT?

a) 10
b) 100
c) 1000
d) 10,000
Answer: (d) 10,000. BJTs can have current gains of up to 10,000, making them useful for amplifying weak signals.

Which of the following is not a parameter that affects the operation of a BJT?

a) Temperature
b) Voltage
c) Frequency
d) Pressure
Answer: (d) Pressure. Pressure does not affect the operation of a BJT.

What is the symbol for a PNP BJT?

a) Arrow pointing in
b) Arrow pointing out
c) Arrow pointing in and out
d) No arrow
Answer: (a) Arrow pointing in. The symbol for a PNP BJT has an arrow pointing inward on the emitter.

Which of the following is not a region of a BJT?

a) Emitter
b) Collector
c) Substrate
d) Base
Answer: (c) Substrate. The substrate is not a region of a BJT, but rather the material on which the BJT is constructed.

Which of the following is true for a BJT in saturation mode?

a) The collector-base junction is reverse-biased
b) The emitter-base junction is reverse-biased
c) The collector-base junction is forward-biased
d) The emitter-base junction is forward-biased
Answer: (c) The collector-base junction is forward-biased in saturation mode. This allows for maximum current flow through the transistor.

What is the common base configuration of a BJT?

a) The base is common to both the emitter and the collector
b) The emitter is common to both the base and the collector
c) The collector is common to both the base and the emitter
d) None of the above
Answer: (a) The base is common to both the emitter and the collector in the common base configuration. This configuration has a low input impedance and a high output impedance.

What is the common emitter configuration of a BJT?

a) The base is common to both the emitter and the collector
b) The emitter is common to both the base and the collector
c) The collector is common to both the base and the emitter
d) None of the above
Answer: (b) The emitter is common to both the base and the collector in the common emitter configuration. This configuration has a high input impedance and a low output impedance.

What is the common collector configuration of a BJT?

a) The base is common to both the emitter and the collector
b) The emitter is common to both the base and the collector
c) The collector is common to both the base and the emitter
d) None of the above
Answer: (c) The collector is common to both the base and the emitter in the common collector configuration. This configuration has a high input impedance and a high output impedance.

What is the small signal model for a BJT?

a) The Ebers-Moll model
b) The Gummel-Poon model
c) The hybrid-pi model
d) The Shockley diode model
Answer: (c) The hybrid-pi model is the small signal model for a BJT. This model is useful for analyzing the behavior of a transistor in a linear amplifier circuit.

What is the cutoff frequency of a BJT?

a) The frequency at which the transistor switches from active mode to saturation mode
b) The frequency at which the transistor switches from active mode to cut-off mode
c) The frequency at which the transistor ceases to amplify signals
d) The frequency at which the transistor begins to amplify signals
Answer: (c) The cutoff frequency of a BJT is the frequency at which the transistor ceases to amplify signals effectively. This frequency is determined by the transistor’s internal capacitances and its external circuitry.

Which of the following is a disadvantage of using a BJT in an amplifier circuit compared to a MOSFET?

a) BJTs are more expensive than MOSFETs
b) BJTs have lower input impedance than MOSFETs
c) BJTs have lower gain-bandwidth product than MOSFETs
d) BJTs have higher input capacitance than MOSFETs
Answer: (d) BJTs have higher input capacitance than MOSFETs, which can cause issues with high-frequency response and stability in amplifier circuits.

In a common emitter amplifier circuit with a BJT, which of the following is true?

a) The input signal is applied to the emitter terminal
b) The input signal is applied to the base terminal
c) The input signal is applied to the collector terminal
d) The input signal is applied to all three terminals simultaneously
Answer: (b) The input signal is applied to the base terminal of the BJT in a common emitter amplifier circuit.

In a common collector amplifier circuit with a BJT, which of the following is true?

a) The input signal is applied to the emitter terminal
b) The input signal is applied to the base terminal
c) The input signal is applied to the collector terminal
d) The input signal is applied to all three terminals simultaneously
Answer: (c) The input signal is applied to the collector terminal of the BJT in a common collector amplifier circuit.

In a common base amplifier circuit with a BJT, which of the following is true?

a) The input signal is applied to the emitter terminal
b) The input signal is applied to the base terminal
c) The input signal is applied to the collector terminal
d) The input signal is applied to all three terminals simultaneously
Answer: (a) The input signal is applied to the emitter terminal of the BJT in a common base amplifier circuit.

Which of the following is a common application of BJTs?

a) Power generation
b) Microcontroller programming
c) Amplifier circuits
d) Data storage
Answer: (c) Amplifier circuits are a common application of BJTs, as they can be used to amplify signals in a wide range of electronic devices and systems.

What is the role of the base terminal in a BJT?

a) To control the current flow between the emitter and collector
b) To provide a low-impedance connection to ground
c) To provide a high-impedance connection to the input signal
d) To provide a voltage reference for the emitter and collector
Answer: (a) The base terminal in a BJT controls the current flow between the emitter and collector terminals, and can be used to amplify signals.

What is the function of the emitter terminal in a BJT?

a) To control the current flow between the base and collector
b) To provide a low-impedance connection to ground
c) To provide a high-impedance connection to the input signal
d) To provide a voltage reference for the base and collector
Answer: (b) The emitter terminal in a BJT provides a low-impedance connection to the ground, which is important for biasing and stabilizing the transistor.

What is the function of the collector terminal in a BJT?

a) To control the current flow between the base and emitter
b) To provide a low-impedance connection to ground
c) To provide a high-impedance connection to the output signal
d) To provide a voltage reference for the base and emitter
Answer: (c) The collector terminal in a BJT provides a high-impedance connection to the output signal, which is important for amplification and signal processing.

In a BJT, the current amplification factor is known as:

a) Voltage gain
b) Power gain
c) Transconductance
d) Current gain
Answer: (d) The current amplification factor in a BJT is known as the current gain.

The common-emitter configuration of a BJT amplifier has a voltage gain of 50 and an input resistance of 100 ohms. What is the output resistance?

a) 50 ohms
b) 100 ohms
c) 2500 ohms
d) 5000 ohms
Answer: (d) The output resistance of a common-emitter amplifier can be approximated as the inverse of the transistor’s current gain, multiplied by the load resistance. In this case, the load resistance is not given, so we can assume a value of 1000 ohms. Using the given voltage gain of 50, we can calculate the current gain as 50/0.02 = 2500. Therefore, the output resistance is approximately (1/2500)*1000 = 0.4 ohms, which is very low. This is not a realistic output resistance for a BJT amplifier, so we can assume that the load resistance is much higher than 1000 ohms.

In a BJT, the base-emitter junction is normally:

a) Forward-biased
b) Reverse-biased
c) Unbiased
d) Short-circuited
Answer: (a) The base-emitter junction in a BJT is normally forward-biased, which allows current to flow between the base and emitter terminals.

In a BJT, the collector-emitter junction is normally:

a) Forward-biased
b) Reverse-biased
c) Unbiased
d) Short-circuited
Answer: (b) The collector-emitter junction in a BJT is normally reverse-biased, which prevents current from flowing between the collector and emitter terminals.

In a BJT amplifier circuit, which of the following parameters affects the voltage gain?

a) Input resistance
b) Output resistance
c) Current gain
d) Transconductance
Answer: (c) The current gain of a BJT affects the voltage gain of an amplifier circuit, as it determines the amount of current amplification between the input and output signals.

Which of the following statements is true about the voltage and current polarities in an NPN transistor?

a) The voltage polarities are positive at the base and negative at the emitter and collector, and the current polarities are into the base and out of the emitter and collector.
b) The voltage polarities are negative at the base and positive at the emitter and collector, and the current polarities are into the base and out of the emitter and collector.
c) The voltage polarities are positive at the base and negative at the emitter and collector, and the current polarities are out of the base and into the emitter and collector.
d) The voltage polarities are negative at the base and positive at the emitter and collector, and the current polarities are out of the base and into the emitter and collector.
Answer: (a) In an NPN transistor, the voltage polarities are positive at the base and negative at the emitter and collector, and the current polarities are into the base and out of the emitter and collector.

Which of the following statements is true about the voltage and current polarities in a PNP transistor?

a) The voltage polarities are positive at the base and negative at the emitter and collector, and the current polarities are into the base and out of the emitter and collector.
b) The voltage polarities are negative at the base and positive at the emitter and collector, and the current polarities are into the base and out of the emitter and collector.
c) The voltage polarities are positive at the base and negative at the emitter and collector, and the current polarities are out of the base and into the emitter and collector.
d) The voltage polarities are negative at the base and positive at the emitter and collector, and the current polarities are out of the base and into the emitter and collector.
Answer: (b) In a PNP transistor, the voltage polarities are negative at the base and positive at the emitter and collector, and the current polarities are into the base and out of the emitter and collector.

In a BJT, the base current is typical:

a) Very small compared to the collector and emitter currents
b) About the same as the collector current and much larger than the emitter current
c) About the same as the emitter current and much larger than the collector current
d) About the same as the collector and emitter currents
Answer: (a) The base current in a BJT is typically very small compared to the collector and emitter currents, which is why BJTs are often used as current-controlled devices.

In a BJT, the collector current is typical:

a) Very small compared to the base and emitter currents
b) About the same as the base currency and much smaller than the emitter’s current
c) About the same as the emitter current and much smaller than the base current
d) About the same as the base and emitter currents
Answer: (c) The collector current in a BJT is typically about the same as the emitter current and much smaller than the base current. This is because the collector current is controlled by the base current, but amplified by the transistor’s current gain.

Which of the following is not a symbol used to represent a BJT?

a) PNP
b) NPN
c) HFE
d) β
Answer: (c) HFE is not a symbol used to represent a BJT. It is a parameter used to describe the current gain of the transistor.

The ratio of the collector current to the base current in a BJT is known as:

a) HFE
b) β
c) α
d) γ
Answer: (b) The ratio of the collector current to the base current in a BJT is known as β or the common-emitter current gain.

The ratio of the collector current to the emitter current in a BJT is known as:

a) HFE
b) β
c) α
d) γ
Answer: (c) The ratio of the collector current to the emitter current in a BJT is known as α or the common-base current gain.

What is the function of the collector in a BJT?

a) To provide a low-resistance path for the current flow
b) To control the flow of current between the base and emitter
c) To amplify the current flowing through the base
d) To provide a reference voltage for the base and emitter
Answer: (a) The function of the collector in a BJT is to provide a low-resistance path for current flow between the emitter and the power supply.

What is the function of the base in a BJT?

a) To provide a low-resistance path for the current flow
b) To control the flow of current between the collector and emitter
c) To amplify the current flowing through the collector
d) To provide a reference voltage for the collector and emitter
Answer: (b) The function of the base in a BJT is to control the flow of current between the collector and emitter by varying the amount of current flowing into the base.

What is the function of the emitter in a BJT?

a) To provide a low-resistance path for the current flow
b) To control the flow of current between the collector and base
c) To amplify the current flowing through the collector
d) To provide a reference voltage for the collector and base
Answer: (a) The function of the emitter in a BJT is to provide a low-resistance path for current flow between the base and the power supply.

In a PNP transistor, the majority of carriers in the base are:

a) Electrons
b) Holes
c) Protons
d) Neutrons
Answer: (b) In a PNP transistor, the majority of carriers in the base are holes.

In an NPN transistor, the majority of carriers in the base are:

a) Electrons
b) Holes
c) Protons
d) Neutrons
Answer: (a) In an NPN transistor, the majority of carriers in the base are electrons.

Which of the following is a typical application of a BJT?

a) Amplification of signals
b) Rectification of signals
c) Filtering of signals
d) None of the above
Answer: (a) Amplification of signals is a typical application of a BJT.

Which of the following configurations provides the highest current gain in a BJT?

a) Common-emitter
b) Common-base
c) Common-collector
d) Both (a) and (c)
Answer: (a) Common-emitter configuration provides the highest current gain in a BJT.

Which of the following configurations provides the highest voltage gain in a BJT?

a) Common-emitter
b) Common-base
c) Common-collector
d) Both (a) and (c)
Answer: (b) Common-base configuration provides the highest voltage gain in a BJT.

Which of the following is a disadvantage of using a BJT?

a) High input impedance
b) High output impedance
c) Limited bandwidth
d) Low power consumption
Answer: (c) Limited bandwidth is a disadvantage of using a BJT.

Which of the following is an advantage of using a BJT?

a) High input impedance
b) High output impedance
c) High bandwidth
d) Low power consumption
Answer: (a) High input impedance is an advantage of using a BJT.

The output characteristics of a BJT show the relationship between:

a) Collector current and base voltage
b) Collector voltage and base current
c) Emitter current and collector voltage
d) Emitter voltage and collector current
Answer: (b) The output characteristics of a BJT show the relationship between collector voltage and base current.

The input characteristics of a BJT show the relationship between:

a) Collector current and base voltage
b) Collector voltage and base current
c) Emitter current and collector voltage
d) Emitter voltage and collector current
Answer: (a) The input characteristics of a BJT show the relationship between collector current and base voltage.

In which region of operation does a BJT act as a linear amplifier?

a) Saturation region
b) Cut-off region
c) Active region
d) Reverse-active region
Answer: (c) A BJT acts as a linear amplifier in the active region of operation.

What is the function of the base in a BJT?

a) To control the flow of current between the collector and emitter
b) To provide a path for the majority of carriers to move from emitter to collector
c) To provide mechanical support to the transistor
d) To provide a heat sink to dissipate heat generated by the transistor
Answer: (a) The function of the base in a BJT is to control the flow of current between the collector and emitter.

Which of the following is true about the doping concentration in the base region of a BJT?

a) It is higher than the doping concentration in the collector region
b) It is higher than the doping concentration in the emitter region
c) It is lower than the doping concentration in the collector region
d) It is lower than the doping concentration in the emitter region
Answer: (d) The doping concentration in the base region of a BJT is lower than the doping concentration in the emitter region.

Which of the following is true about the doping concentration in the collector region of a BJT?

a) It is higher than the doping concentration in the base region
b) It is higher than the doping concentration in the emitter region
c) It is lower than the doping concentration in the base region
d) It is lower than the doping concentration in the emitter region
Answer: (b) The doping concentration in the collector region of a BJT is higher than the doping concentration in the emitter region.

What is the effect of increasing the base doping concentration in a BJT?

a) It increases the collector’s current
b) It decreases the collector’s current
c) It does not affect the collector’s current
d) It increases the base current
Answer: (a) Increasing the base doping concentration in a BJT increases the collector current.

What is the effect of increasing the collector doping concentration in a BJT?

a) It increases the collector’s current
b) It decreases the collector’s current
c) It does not affect the collector’s current
d) It increases the base current
Answer: (c) Increasing the collector doping concentration in a BJT does not affect the collector current.

What is the effect of decreasing the base width in a BJT?

a) It increases the collector’s current
b) It decreases the collector’s current
c) It does not affect the collector’s current
d) It increases the base current
Answer: (a) Decreasing the base width in a BJT increases the collector current.

What is the effect of increasing the collector voltage in a BJT?

a) It increases the collector’s current
b) It decreases the collector’s current
c) It does not affect the collector’s current
d) It increases the base current
Answer: (a) Increasing the collector voltage in a BJT increases the collector current.

What is the effect of increasing the base-emitter voltage in a BJT?

a) It increases the collector’s current
b) It decreases the collector’s current
c) It does not affect the collector’s current
d) It increases the base current
Answer: (a) Increasing the base-emitter voltage in a BJT increases the collector current.

What is the effect of increasing the collector current in a BJT?

a) It increases the base current
b) It decreases the base current
c) It does not affect the base current
d) It increases the emitter’s current
Answer: (a) Increasing the collector current in a BJT increases the base current.

What is the effect of increasing the collector resistance in a BJT circuit?

a) It increases the collector’s current
b) It decreases the collector’s current
c) It does not affect the collector’s current
d) It increases the base current
Answer: (b) Increasing the collector resistance in a BJT circuit decreases the collector current.

Which of the following is true about the input impedance of a BJT amplifier?

a) It is high for common-emitter configuration
b) It is high for common-base configuration
c) It is high for common-collector configuration
d) It is the same for all configurations
Answer: (b) The input impedance of a BJT amplifier is high for common-base configuration.

What is the function of the coupling capacitor in a BJT amplifier circuit?

a) To block DC voltage from entering the next stage
b) To provide a bias voltage to the transistor
c) To provide mechanical support to the transistor
d) To provide a heat sink to dissipate heat generated by the transistor
Answer: (a) The function of the coupling capacitor in a BJT amplifier circuit is to block DC voltage from entering the next stage.

What is the function of the bypass capacitor in a BJT amplifier circuit?

a) To block AC voltage from entering the next stage
b) To provide a bias voltage to the transistor
c) To provide mechanical support to the transistor
d) To provide a heat sink to dissipate heat generated by the transistor
Answer: (b) The function of the bypass capacitor in a BJT amplifier circuit is to provide a bias voltage to the transistor.

Which of the following is true about the common-base configuration of a BJT amplifier?

a) The input impedance is high
b) The output impedance is high
c) The voltage gain is less than one
d) The current gain is less than one
Answer: (c) The voltage gain of the common-base configuration of a BJT amplifier is less than one.

Which of the following is true about the common-emitter configuration of a BJT amplifier?

a) The input impedance is high
b) The output impedance is high
c) The voltage gain is high
d) The current gain is high
Answer: (c) The voltage gain of the common-emitter configuration of a BJT amplifier is high.

Which of the following is true about the common-collector configuration of a BJT amplifier?

a) The input impedance is high
b) The output impedance is high
c) The voltage gain is less than one
d) The current gain is less than one
Answer: (a) The input impedance of the common-collector configuration of a BJT amplifier is high.

What is the function of a Darlington pair transistor?

a) To provide high current gain
b) To provide high-voltage gain
c) To provide a high input impedance
d) To provide a high output impedance
Answer: (a) The function of a Darlington pair transistor is to provide high current gain.

Which of the following is true about the Darlington pair configuration?

a) The input impedance is high
b) The output impedance is high
c) The voltage gain is high
d) The current gain is high
Answer: (d) The current gain of the Darlington pair configuration is high.

What is the function of the biasing circuit in a BJT amplifier?

a) To provide a stable operating point for the transistor
b) To provide mechanical support to the transistor
c) To provide a heat sink to dissipate heat generated by the transistor
d) To provide coupling between different stages of the amplifier
Answer: (a) The function of the biasing circuit in a BJT amplifier is to provide a stable operating point for the transistor.

Which of the following is true about the operating point of a BJT transistor?

a) It should be at the center of the load line
b) It should be at the intersection of the load line and the DC load line
c) It should be at the intersection of the load line and the AC load line
d) It should be at the center of the AC load line
Answer: (b) The operating point of a BJT transistor should be at the intersection of the load line and the DC load line.

What is the purpose of the load line in a BJT circuit?

a) To represent the load connected to the transistor
b) To represent the operating characteristics of the transistor
c) To determine the operating point of the transistor
d) To provide a stable operating point for the transistor
Answer: (c) The purpose of the load line in a BJT circuit is to determine the operating point of the transistor.

What is the purpose of the DC load line in a BJT circuit?

a) To determine the operating point of the transistor
b) To represent the load connected to the transistor
c) To represent the operating characteristics of the transistor
d) To provide a stable operating point for the transistor
Answer: (a) The purpose of the DC load line in a BJT circuit is to determine the operating point of the transistor.

What is the purpose of the AC load line in a BJT circuit?

a) To determine the operating point of the transistor
b) To represent the load connected to the transistor
c) To represent the operating characteristics of the transistor
d) To provide a stable operating point for the transistor
Answer: (c) The purpose of the AC load line in a BJT circuit is to represent the operating characteristics of the transistor.

Which of the following is true about the Q-point of a BJT transistor?

a) It represents the operating point of the transistor
b) It represents the peak value of the AC voltage
c) It represents the DC voltage applied to the transistor
d) It represents the voltage at which the transistor switches ON
Answer: (a) The Q-point of a BJT transistor represents the operating point of the transistor.

What is the function of the base resistor in a BJT circuit?

a) To limit the base current
b) To provide mechanical support to the transistor
c) To provide a heat sink to dissipate heat generated by the transistor
d) To provide a stable operating point for the transistor
Answer: (a) The function of the base resistor in a BJT circuit is to limit the base current.

What is the function of the emitter resistor in a BJT circuit?

a) To limit the emitter’s current
b) To provide mechanical support to the transistor
c) To provide a heat sink to dissipate heat generated by the transistor
d) To provide a stable operating point for the transistor
Answer: (d) The function of the emitter resistor in a BJT circuit is to provide a stable operating point for the transistor.

What is the effect of increasing the base resistor in a BJT circuit?

a) It increases the base current
b) It decreases the base current
c) It has no effect on the base current
d) It increases the collector’s current
Answer: (b) Increasing the base resistor in a BJT circuit decreases the base current.

What is the effect of decreasing the collector resistor in a BJT circuit?

a) It increases the collector’s current
b) It decreases the collector’s current
c) It has no effect on the collector’s current
d) It increases the base current
Answer: (a) Decreasing the collector resistor in a BJT circuit increases the collector current.

What is the function of the coupling capacitor in a BJT circuit?

a) To provide a DC path between two stages of the amplifier
b) To provide a high-pass filter between two stages of the amplifier
c) To provide a low-pass filter between two stages of the amplifier
d) To provide an AC path between two stages of the amplifier
Answer: (d) The function of the coupling capacitor in a BJT circuit is to provide an AC path between two stages of the amplifier.

Which of the following is true about the input impedance of a BJT amplifier?

a) It is always high
b) It is always low
c) It depends on the type of biasing used
d) It is independent of the type of biasing used
Answer: (c) The input impedance of a BJT amplifier depends on the type of biasing used.

Which of the following is true about the output impedance of a BJT amplifier?

a) It is always high
b) It is always low
c) It depends on the type of biasing used
d) It is independent of the type of biasing used
Answer: (c) The output impedance of a BJT amplifier depends on the type of biasing used.

What is the purpose of the bypass capacitor in a BJT circuit?

a) To provide a DC path for the signal
b) To provide an AC path for the signal
c) To remove the DC component from the signal
d) To remove the AC component from the signal
Answer: (c) The purpose of the bypass capacitor in a BJT circuit is to remove the DC component from the signal.

Which of the following is true about the frequency response of a BJT amplifier?

a) It is always flat
b) It is always low-pass
c) It is always high-pass
d) It depends on the type of biasing used
Answer: (d) The frequency response of a BJT amplifier depends on the type of biasing used.

What is the purpose of the bypass capacitor in a BJT power amplifier?

a) To remove the DC component from the signal
b) To provide a DC path for the signal
c) To provide an AC path for the signal
d) To remove the AC component from the signal
Answer: (a) The purpose of the bypass capacitor in a BJT power amplifier is to remove the DC component from the signal.

What is the function of the coupling transformer in a BJT amplifier?

a) To provide a DC path between two stages of the amplifier
b) To provide an AC path between two stages of the amplifier
c) To provide impedance matching between two stages of the amplifier
d) To remove the DC component from the signal
Answer: (c) The function of the coupling transformer in a BJT amplifier is to provide impedance matching between two stages of the amplifier.

Which of the following is true about the efficiency of a BJT power amplifier?

a) It is always high
b) It is always low
c) It depends on the type of biasing used
d) It is independent of the type of biasing used
Answer: (c) The efficiency of a BJT power amplifier depends on the type of biasing used.

What is the purpose of the biasing circuit in a BJT amplifier?

a) To provide a path for the signal
b) To provide a path for the DC’s current
c) To provide a path for the AC current
d) To remove the DC component from the signal
Answer: (b) The purpose of the biasing circuit in a BJT amplifier is to provide a path for the DC current.

Which of the following is true about the operating point of a BJT amplifier?

a) It is always fixed
b) It can be adjusted by changing the biasing
c) It is independent of the biasing
d) It is determined by the type of transistor used
Answer: (b) The operating point of a BJT amplifier can be adjusted by changing the biasing.

Which of the following is true about the gain of a BJT amplifier?

a) It is always constant
b) It is always variable
c) It depends on the type of biasing used
d) It is independent of the type of biasing used
Answer: (c) The gain of a BJT amplifier depends on the type of biasing used.

What is the purpose of the emitter resistor in a BJT amplifier?

a) To provide a DC path for the signal
b) To provide an AC path for the signal
c) To provide negative feedback
d) To remove the AC component from the signal
Answer: (c) The purpose of the emitter resistor in a BJT amplifier is to provide negative feedback.

Which of the following is true about the phase shift of a BJT amplifier?

a) It is always zero
b) It is always positive
c) It is always negative
d) It depends on the type of biasing used
Answer: (d) The phase shift of a BJT amplifier depends on the type of biasing used.

What is the function of the collector resistor in a BJT amplifier?

a) To provide a DC path for the signal
b) To provide an AC path for the signal
c) To provide negative feedback
d) To remove the AC component from the signal
Answer: (c) The function of the collector resistor in a BJT amplifier is to provide negative feedback.

What is the purpose of the bypass capacitor in a BJT power amplifier?

a) To provide a DC path for the signal
b) To provide an AC path for the signal
c) To remove the DC component from the signal
d) To remove the AC component from the signal
Answer: (c) The purpose of the bypass capacitor in a BJT power amplifier is to remove the DC component from the signal.

Which of the following is true about the saturation region of a BJT?

a) The collector-emitter voltage is zero
b) The base-emitter voltage is zero
c) The collector current is zero
d) The base current is zero
Answer: (a) In the saturation region of a BJT, the collector-emitter voltage is zero.

What is the function of the base resistor in a BJT amplifier?

a) To provide a DC path for the signal
b) To provide an AC path for the signal
c) To provide negative feedback
d) To limit the base current
Answer: (d) The function of the base resistor in a BJT amplifier is to limit the base current.

What is the difference between NPN and PNP transistors?

a) The material used in the base region
b) The direction of the majority of carriers in the base region
c) The direction of the minority carriers in the emitter region
d) The direction of the minority carriers in the collector region
Answer: (b) The main difference between NPN and PNP transistors is the direction of the majority of carriers in the base region.

What is the purpose of the coupling capacitor in a BJT amplifier?

a) To provide a DC path for the signal
b) To provide an AC path for the signal
c) To remove the DC component from the signal
d) To remove the AC component from the signal
Answer: (b) The purpose of the coupling capacitor in a BJT amplifier is to provide an AC path for the signal.

What is the typical value of the beta of a BJT transistor?

a) 1
b) 10
c) 100
d) 1000
Answer: (c) The typical value of the beta of a BJT transistor is around 100.

What is the maximum power dissipation of a typical small signal BJT transistor?

a) 100 mW
b) 500 mW
c) 1 W
d) 5 W
Answer: (a) The maximum power dissipation of a typical small signal BJT transistor is around 100 mW.

What is the typical voltage drop across the base-emitter junction of a silicon BJT transistor?

a) 0.1 V
b) 0.5 V
c) 0.7 V
d) 1.0 V
Answer: (c) The typical voltage drop across the base-emitter junction of a silicon BJT transistor is around 0.7 V.

What is the typical voltage drop across the collector-emitter junction of a saturated BJT transistor?

a) 0.1 V
b) 0.5 V
c) 0.7 V
d) 1.0 V
Answer: (a) The typical voltage drop across the collector-emitter junction of a saturated BJT transistor is very small, around 0.1 V.

What is the typical voltage gain of a BJT amplifier?

a) 1
b) 10
c) 100
d) 1000
Answer: (c) The typical voltage gain of a BJT amplifier is around 100.