Electronic Devices MCQ & Objective Questions
Understanding electronic devices is crucial for students preparing for school exams and competitive tests. These devices form the backbone of modern technology and are frequently featured in exam syllabi. Practicing MCQs and objective questions on electronic devices not only enhances your knowledge but also boosts your confidence, helping you score better in your exams. Dive into our collection of practice questions to master this essential topic!
What You Will Practise Here
Fundamentals of electronic devices and their classifications
Key concepts of diodes, transistors, and integrated circuits
Important formulas related to current, voltage, and resistance
Definitions of key terms like semiconductor, conductor, and insulator
Diagrams illustrating circuit designs and device functionalities
Theory on the working principles of various electronic components
Applications of electronic devices in real-world scenarios
Exam Relevance
The topic of electronic devices is integral to the curriculum of CBSE, State Boards, NEET, and JEE. Students can expect questions that test their understanding of basic concepts, device functionalities, and practical applications. Common question patterns include multiple-choice questions that assess both theoretical knowledge and problem-solving skills, making it essential to be well-prepared with important electronic devices questions for exams.
Common Mistakes Students Make
Confusing the functions of different types of diodes and transistors
Misunderstanding the relationship between voltage, current, and resistance
Overlooking the significance of circuit diagrams in problem-solving
Failing to apply theoretical concepts to practical scenarios
FAQs
Question: What are the most important electronic devices to study for exams?Answer: Focus on diodes, transistors, and operational amplifiers, as they are frequently tested in various exams.
Question: How can I improve my understanding of electronic devices?Answer: Regular practice with MCQs and objective questions will help reinforce your concepts and improve retention.
Don't wait! Start solving our Electronic Devices MCQ questions today and test your understanding. With consistent practice, you can master this topic and excel in your exams!
Q. In small-signal models, what does the term 'r_pi' represent?
A.
The input resistance of a BJT
B.
The output resistance of a BJT
C.
The transconductance of a BJT
D.
The thermal voltage
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Solution
In small-signal models, 'r_pi' represents the input resistance of a BJT, which is crucial for analyzing amplifier circuits.
Correct Answer:
A
— The input resistance of a BJT
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Q. In small-signal models, what does the term 'transconductance' (gm) represent?
A.
The ratio of output voltage to input current
B.
The ratio of input voltage to output current
C.
The ratio of output current to input voltage
D.
The ratio of input current to output voltage
Show solution
Solution
Transconductance (gm) is defined as the ratio of output current to input voltage in small-signal models.
Correct Answer:
C
— The ratio of output current to input voltage
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Q. In small-signal models, what does the term 'transconductance' refer to?
A.
The ratio of output current to input voltage
B.
The ratio of input current to output voltage
C.
The gain of the amplifier
D.
The resistance of the transistor
Show solution
Solution
Transconductance is defined as the ratio of output current to input voltage in small-signal models.
Correct Answer:
A
— The ratio of output current to input voltage
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Q. In small-signal models, what does the transconductance (gm) represent?
A.
The ratio of output current to input voltage
B.
The ratio of input current to output voltage
C.
The change in output current per change in input voltage
D.
The change in input voltage per change in output current
Show solution
Solution
Transconductance (gm) is defined as the change in output current per change in input voltage in small-signal models.
Correct Answer:
C
— The change in output current per change in input voltage
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Q. In small-signal models, which parameter represents the transconductance of a FET?
Show solution
Solution
The transconductance of a FET is represented by the parameter 'gm', which indicates the change in drain current with respect to gate-source voltage.
Correct Answer:
A
— gm
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Q. In the context of FETs, what does 'Vgs' represent?
A.
Gate-source voltage
B.
Drain-source voltage
C.
Gate-drain voltage
D.
Source-drain voltage
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Solution
Vgs represents the voltage difference between the gate and source terminals of a FET.
Correct Answer:
A
— Gate-source voltage
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Q. In the context of FETs, what does 'Vgs' stand for?
A.
Gate-source voltage
B.
Drain-source voltage
C.
Gate-drain voltage
D.
Source-drain voltage
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Solution
Vgs stands for gate-source voltage, which is crucial for controlling the FET operation.
Correct Answer:
A
— Gate-source voltage
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Q. What does the small-signal model of a diode help analyze?
A.
High-frequency response
B.
DC biasing conditions
C.
Small variations around an operating point
D.
Thermal stability
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Solution
The small-signal model of a diode is used to analyze small variations around an operating point.
Correct Answer:
C
— Small variations around an operating point
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Q. What does the term 'threshold voltage' refer to in MOSFETs?
A.
The maximum voltage rating
B.
The minimum gate voltage required to create a conducting channel
C.
The voltage drop across the drain-source
D.
The voltage at which breakdown occurs
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Solution
The threshold voltage is the minimum gate voltage required to induce a conducting channel between the source and drain in a MOSFET.
Correct Answer:
B
— The minimum gate voltage required to create a conducting channel
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Q. What happens to a diode when it is reverse-biased?
A.
It conducts current freely
B.
It blocks current flow
C.
It generates heat
D.
It amplifies the signal
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Solution
When a diode is reverse-biased, it blocks current flow, preventing it from conducting until the breakdown voltage is reached.
Correct Answer:
B
— It blocks current flow
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Q. What happens to the current in a diode when the reverse voltage exceeds the breakdown voltage?
A.
It stops conducting
B.
It conducts in the reverse direction
C.
It enters a state of thermal runaway
D.
It conducts in the forward direction
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Solution
When the reverse voltage exceeds the breakdown voltage, the diode conducts in the reverse direction, which can lead to damage if not controlled.
Correct Answer:
B
— It conducts in the reverse direction
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Q. What happens to the drain current in a MOSFET when the gate-source voltage increases?
A.
It decreases
B.
It remains constant
C.
It increases
D.
It becomes zero
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Solution
As the gate-source voltage increases, the drain current in a MOSFET typically increases, assuming the device is in saturation.
Correct Answer:
C
— It increases
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Q. What happens to the output of an operational amplifier when the input voltage exceeds the supply voltage?
A.
Output saturates
B.
Output increases linearly
C.
Output decreases
D.
Output becomes zero
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Solution
When the input voltage exceeds the supply voltage, the output of the operational amplifier saturates.
Correct Answer:
A
— Output saturates
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Q. What happens to the output of an operational amplifier when the input voltages are equal?
A.
Output is positive
B.
Output is negative
C.
Output is zero
D.
Output is infinite
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Solution
When the input voltages of an operational amplifier are equal, the output is zero.
Correct Answer:
C
— Output is zero
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Q. What is a small-signal model used for in communication systems?
A.
To analyze large signal behavior
B.
To simplify the analysis of linear circuits
C.
To design power amplifiers
D.
To measure frequency response
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Solution
Small-signal models simplify the analysis of linear circuits by approximating the behavior around a bias point.
Correct Answer:
B
— To simplify the analysis of linear circuits
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Q. What is the bandgap energy of silicon at room temperature?
A.
0.1 eV
B.
1.1 eV
C.
2.0 eV
D.
3.5 eV
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Solution
Silicon has a bandgap energy of approximately 1.1 eV at room temperature, which is crucial for its semiconductor properties.
Correct Answer:
B
— 1.1 eV
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Q. What is the depletion region in a diode?
A.
The area where current flows
B.
The area with no charge carriers
C.
The area of maximum conductivity
D.
The area where voltage is applied
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Solution
The depletion region in a diode is the area where there are no free charge carriers, formed at the junction of p-type and n-type materials.
Correct Answer:
B
— The area with no charge carriers
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Q. What is the depletion region in a semiconductor?
A.
A region with excess charge carriers
B.
A region with no charge carriers
C.
A region where electrons are free to move
D.
A region that conducts electricity
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Solution
The depletion region is an area in a semiconductor where charge carriers are absent, creating an electric field.
Correct Answer:
B
— A region with no charge carriers
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Q. What is the effect of increasing the frequency on the gain of an operational amplifier?
A.
Gain increases
B.
Gain decreases
C.
Gain remains constant
D.
Gain becomes zero
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Solution
As frequency increases, the gain of an operational amplifier typically decreases due to bandwidth limitations.
Correct Answer:
B
— Gain decreases
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Q. What is the effect of increasing the gain of an operational amplifier?
A.
Increased bandwidth
B.
Decreased bandwidth
C.
No effect on bandwidth
D.
Increased input impedance
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Solution
Increasing the gain of an operational amplifier typically decreases its bandwidth due to the gain-bandwidth product.
Correct Answer:
B
— Decreased bandwidth
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Q. What is the effect of negative feedback in an operational amplifier circuit?
A.
Increases gain
B.
Decreases gain
C.
Stabilizes gain
D.
Reverses phase
Show solution
Solution
Negative feedback stabilizes the gain of an operational amplifier and improves linearity.
Correct Answer:
C
— Stabilizes gain
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Q. What is the effect of negative feedback on the bandwidth of an operational amplifier?
A.
Increases bandwidth
B.
Decreases bandwidth
C.
No effect
D.
Depends on the configuration
Show solution
Solution
Negative feedback in an operational amplifier increases the bandwidth of the amplifier.
Correct Answer:
A
— Increases bandwidth
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Q. What is the effect of temperature on the forward voltage drop of a diode?
A.
It increases
B.
It decreases
C.
It remains constant
D.
It becomes zero
Show solution
Solution
As temperature increases, the forward voltage drop of a diode typically decreases.
Correct Answer:
B
— It decreases
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Q. What is the effect of temperature on the forward voltage drop of a silicon diode?
A.
Increases with temperature
B.
Decreases with temperature
C.
Remains constant
D.
Varies randomly
Show solution
Solution
The forward voltage drop of a silicon diode decreases with an increase in temperature due to increased carrier activity.
Correct Answer:
B
— Decreases with temperature
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Q. What is the energy band gap in semiconductors?
A.
The energy required to free an electron
B.
The energy of the conduction band
C.
The energy of the valence band
D.
The energy lost during conduction
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Solution
The energy band gap in semiconductors is the energy required to free an electron from the valence band to the conduction band.
Correct Answer:
A
— The energy required to free an electron
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Q. What is the function of a bypass capacitor in a BJT amplifier circuit?
A.
To increase the gain
B.
To stabilize the bias point
C.
To filter out noise
D.
To provide AC coupling
Show solution
Solution
A bypass capacitor is used in a BJT amplifier circuit to increase the gain by providing a low impedance path for AC signals, effectively bypassing the emitter resistor.
Correct Answer:
A
— To increase the gain
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Q. What is the function of a capacitor in a rectifier circuit?
A.
To increase current
B.
To filter out noise
C.
To store charge
D.
To convert AC to DC
Show solution
Solution
In a rectifier circuit, a capacitor is used to store charge and smooth out the output voltage.
Correct Answer:
C
— To store charge
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Q. What is the function of a diode bridge?
A.
To amplify signals
B.
To convert AC to DC
C.
To regulate voltage
D.
To filter signals
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Solution
A diode bridge is used to convert alternating current (AC) to direct current (DC) by allowing both halves of the AC waveform to be used.
Correct Answer:
B
— To convert AC to DC
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Q. What is the function of a mixer in communication systems?
A.
To amplify signals
B.
To convert signals to different frequencies
C.
To filter unwanted signals
D.
To rectify signals
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Solution
Mixers are used to convert signals from one frequency to another, essential in modulation and demodulation processes.
Correct Answer:
B
— To convert signals to different frequencies
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Q. What is the function of a rectifier in a power supply?
A.
To convert AC to DC
B.
To amplify signals
C.
To filter noise
D.
To regulate voltage
Show solution
Solution
A rectifier's primary function is to convert alternating current (AC) to direct current (DC).
Correct Answer:
A
— To convert AC to DC
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