Analog Electronics MCQ

1. The main difference between a BJT and a FET is:

a) Type of material used
b) Size and weight
c) Current control vs Voltage control
d) Power handling capabilities

Answer:

c) Current control vs Voltage control

Explanation:

The primary difference between Bipolar Junction Transistors (BJTs) and Field-Effect Transistors (FETs) is that BJTs are current-controlled devices, whereas FETs are voltage-controlled.

2. In a diode, the 'P' type material contains:

a) Excess electrons
b) Excess holes
c) Equal number of electrons and holes
d) No charge carriers

Answer:

b) Excess holes

Explanation:

In a semiconductor diode, the P-type material is doped to create excess holes, which act as the majority charge carriers.

3. The purpose of a capacitor in an AC circuit is to:

a) Block DC
b) Allow DC
c) Convert AC to DC
d) Amplify the signal

Answer:

a) Block DC

Explanation:

In AC circuits, capacitors block direct current (DC) while allowing alternating current (AC) to pass through.

4. Operational Amplifiers are used for:

a) Signal amplification
b) Rectification
c) Induction
d) Voltage regulation

Answer:

a) Signal amplification

Explanation:

Operational Amplifiers (Op-Amps) are primarily used for signal amplification purposes in various electronic circuits.

5. The cut-off frequency of an RC low pass filter is determined by:

a) Only resistance (R)
b) Only capacitance (C)
c) Both resistance (R) and capacitance (C)
d) Neither resistance (R) nor capacitance (C)

Answer:

c) Both resistance (R) and capacitance (C)

Explanation:

The cut-off frequency of an RC low pass filter is determined by both the resistance (R) and the capacitance (C) of the circuit.

6. A Zener diode is typically used for:

a) Amplification
b) Voltage regulation
c) Rectification
d) Signal modulation

Answer:

b) Voltage regulation

Explanation:

A Zener diode is commonly used in circuits for voltage regulation, as it can maintain a constant voltage over a range of current.

7. The main characteristic of a Band-Pass Filter is:

a) It allows frequencies below a certain cutoff frequency.
b) It allows frequencies above a certain cutoff frequency.
c) It allows frequencies within a certain range.
d) It blocks all frequencies.

Answer:

c) It allows frequencies within a certain range.

Explanation:

A band-pass filter allows frequencies within a specific range to pass through while attenuating frequencies outside that range.

8. A Bipolar Junction Transistor (BJT) is composed of how many layers of semiconductor material?

a) Two
b) Three
c) Four
d) Five

Answer:

b) Three

Explanation:

A Bipolar Junction Transistor (BJT) is made up of three layers of semiconductor material, forming two PN junctions.

9. The main purpose of a bridge rectifier is to:

a) Convert AC to DC
b) Convert DC to AC
c) Amplify AC signals
d) Regulate voltage

Answer:

a) Convert AC to DC

Explanation:

The primary purpose of a bridge rectifier is to convert alternating current (AC) into direct current (DC).

10. In an NPN transistor, the arrow on the emitter symbol always points:

a) Inward
b) Outward
c) Upward
d) Downward

Answer:

b) Outward

Explanation:

In an NPN transistor, the arrow on the emitter symbol points outward, indicating the direction of conventional current flow.

11. An ideal Op-Amp has:

a) Infinite input impedance
b) Zero output impedance
c) Infinite bandwidth
d) All of the above

Answer:

d) All of the above

Explanation:

An ideal operational amplifier has infinite input impedance, zero output impedance, and infinite bandwidth.

12. In a common emitter configuration, the transistor provides:

a) Current amplification only
b) Voltage amplification only
c) Both current and voltage amplification
d) Neither current nor voltage amplification

Answer:

c) Both current and voltage amplification

Explanation:

A common emitter configuration provides both current and voltage amplification.

13. The primary purpose of a transformer is to:

a) Convert AC to DC
b) Change the voltage level
c) Store electrical energy
d) Rectify signals

Answer:

b) Change the voltage level

Explanation:

The main function of a transformer is to change the voltage level while transferring power from one circuit to another.

14. The ripple factor in a rectifier circuit is a measure of:

a) Efficiency
b) Purity of DC output
c) Power dissipation
d) Frequency response

Answer:

b) Purity of DC output

Explanation:

The ripple factor in a rectifier circuit measures the amount of AC components in the DC output, indicating the purity of the DC output.

15. In an LC circuit, the resonant frequency is determined by:

a) Only inductance (L)
b) Only capacitance (C)
c) Both inductance (L) and capacitance (C)
d) Neither inductance (L) nor capacitance (C)

Answer:

c) Both inductance (L) and capacitance (C)

Explanation:

In an LC circuit, the resonant frequency is determined by both the inductance (L) and the capacitance (C) values.

16. A Darlington pair is used to:

a) Increase input impedance
b) Decrease output impedance
c) Increase current gain
d) Decrease bandwidth

Answer:

c) Increase current gain

Explanation:

A Darlington pair is a configuration of two bipolar transistors to provide a very high current gain.

17. The primary application of a Schmitt Trigger is to:

a) Amplify signals
b) Convert analog signals to digital
c) Filter out noise
d) Stabilize voltage

Answer:

b) Convert analog signals to digital

Explanation:

A Schmitt Trigger is used to convert analog signals into digital by providing a clear distinction between high and low states.

18. In a full-wave rectifier, the number of diodes used is:

a) One
b) Two
c) Three
d) Four

Answer:

d) Four

Explanation:

A full-wave rectifier typically uses four diodes to rectify both halves of the input AC signal.

19. A photodiode is used to:

a) Emit light
b) Detect light
c) Amplify light signals
d) Store light

Answer:

b) Detect light

Explanation:

A photodiode is a semiconductor device that converts light into electrical current, used primarily for light detection.

20. The slew rate of an Op-Amp is defined as:

a) Rate of change of output voltage per unit time
b) Input impedance variation with frequency
c) Output impedance variation with frequency
d) Gain variation with temperature

Answer:

a) Rate of change of output voltage per unit time

Explanation:

The slew rate of an Op-Amp is the maximum rate at which the output voltage can change in response to a change in the input signal.

21. The primary function of a varactor diode is:

a) Voltage regulation
b) Frequency modulation
c) Signal amplification
d) Current rectification

Answer:

b) Frequency modulation

Explanation:

A varactor diode, also known as a varicap, is used primarily for frequency modulation and tuning due to its variable capacitance properties.

22. A resistor's color code is used to indicate its:

a) Power rating
b) Tolerance
c) Resistance value
d) Temperature coefficient

Answer:

c) Resistance value

Explanation:

The color bands on a resistor are used to indicate its resistance value, following a standardized color code.

23. The function of a flyback diode in a circuit is to:

a) Increase current flow
b) Protect against voltage spikes
c) Convert AC to DC
d) Store electrical energy

Answer:

b) Protect against voltage spikes

Explanation:

A flyback diode is used in circuits to protect against voltage spikes, especially in inductive loads.

24. In a differential amplifier, the output is taken from:

a) Only one of the collectors
b) Both bases
c) Between the two collectors
d) The emitter

Answer:

c) Between the two collectors

Explanation:

In a differential amplifier, the output is typically taken from between the two collectors, providing the difference between the two input signals.

25. The primary use of a crystal oscillator is to:

a) Amplify signals
b) Generate high-frequency signals
c) Rectify signals
d) Store electrical energy

Answer:

b) Generate high-frequency signals

Explanation:

A crystal oscillator is used to generate precise, stable high-frequency signals, commonly used in clocks and frequency synthesizers.

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