Basic Electronics Questions for Interview

Electronics Engineering students need to face some Basic Electronics Questions whether they are preparing for an interview or viva voce. So, this article gives you few Basic Electronics Questions for Interview and other competetive exams. 

Generally you need to refer a variety of books in order to cover the ocean of topics in Electronics. To make it easy for you guys, I’ve collected a few basic electronics questions from different topics and organized them into different sections.

Initially, I’ll be concentrating majorly on multiple choice type questions and in the future I’ll add the explanations and some short answer type questions.....

Basic Introduction Questions

1. What is an ideal voltage source?
Answer: A device with zero internal resistance.

2. What is an ideal current source?
Answer: A device with infinite internal resistance.

3. What is a practical voltage source?
Answer: A device with small internal resistance.

4. What is a practical current source?
Answer: A device with large internal resistance.

MCQ:

5. The voltage out of an ideal voltage source is
A. Zero
B. Constant
C. Load resistance dependent
D. Internal resistance dependent

Answer: B

6. The current out of an ideal current source is
A. Zero
B. Constant
C. Load resistance dependent
D. Internal resistance dependent

Answer: B

7. The path between two points along which an electrical current can be carried is called
A. A network
B. A relay
C. A circuit
D. A loop

Answer: C

8. The formula for current as per Ohm’s Law is
A. Voltage / Resistance
B. Resistance * Voltage
C. Voltage + Resistance
D. Resistance / Voltage

Answer: A

9. The unit of electrical resistance is
A. Volt
B. Amp
C. Ohm
D. Coulomb

Answer: C

10. In a constant voltage DC circuit, when the resistance increases, the current will
A. Decrease
B. Stop
C. Increase
D. Remains constant

Answer: A

Basic Semiconductor Theory Questions

1. Number of valence electrons in a silicon atom are
A. 1
B. 4
C. 8
D. 16

Answer: B

2. The most commonly used semiconductor element is
A. Silicon
B. Germanium
C. Gallium
D. Carbon

Answer: A

3. Copper is a
A. Insulator
B. Conductor
C. Semiconductor
D. Super Conductor

Answer: B

4. Number of protons in the nucleus of a silicon atom are
A. 4
B. 14
C. 29
D. 32

Answer: B

5. The valence electron of a conductor are also called as
A. Bound electron
B. Free electron
C. Nucleus
D. Proton

Answer: B

6. An intrinsic semiconductor at room temperature has
A. A few free electrons and holes
B. Many holes
C. Many free electrons
D. No holes

Answer: A

7. At room temperature, an intrinsic semiconductor has some holes in it due to
A. Doping
B. Free electrons
C. Thermal energy
D. Valence electrons

Answer: C

8. The number of holes in an intrinsic semiconductor is
A. Equal to number of free electrons
B. Greater than number of free electrons
C. Less than number of free electrons
D. None of the above

Answer: A

9. Holes act as
A. Atoms
B. Crystals
C. Negative charges
D. Positive charges

Answer: D

10. Pick the odd one in the group
A. Conductor
B. Semiconductor
C. Four valence electrons
D. Crystal structure

Answer: A

11. To produce P-type semiconductors, you need to add
A. Trivalent impurity
B. Carbon
C. Pentavalent impurity
D. Silicon

Answer: A

12. Electrons are the minority carriers in
A. Extrinsic Semiconductors
B. p-type Semiconductors
C. Intrinsic Semiconductors
D. n-type Semiconductors

Answer: D

13. A p-type semiconductor contains
A. Holes and Negative ions
B. Holes and Positive ions
C. Holes and Pentavalent atoms
D. Holes and Donor atoms

Answer: A

14. How many electrons does pentavalent atoms have?
A. 1
B. 3
C. 4
D. 5

Answer: D

15. Negative ions are
A. Atoms that obtained a proton
B. Atoms that lost a proton
C. Atoms that obtained an electron
D. Atoms that lost an electron

Answer: C

Basic Semiconductor Diode Questions

1. Depletion layer is caused by
A. Doping
B. Recombination
C. Barrier potential
D. Ions

Answer: B

2. The reverse current in a diode is usually
A. Very small
B. Very large
C. Zero
D. In the breakdown region

Answer: A

3. Avalanche in Diode occurs at
A. Barrier potential
B. Depletion layer
C. Knee voltage
D. Breakdown voltage

Answer: D

4. The potential barrier of a silicon diode is
A. 0.3 V
B. 0.7 V
C. 1 V
D. 5V

Answer: B

5. The reverse saturation current in a Silicon Diode is _____ than that of Germanium Diode
A. Equal
B. Higher
C. Lower
D. Depends on temperature

Answer: C

6. A Diode is a
A. Bilateral Device
B. Nonlinear Device
C. Linear Device
D. Unipolar Device

Answer: C

7. The diode current is large for which condition
A. Forward Bias
B. Inverse Bias
C. Poor Bias
D. Reverse Bias

Answer: A

8. The output voltage signal of a bridge rectifier is
A. Half-wave
B. Full-wave
C. Bridge-rectified signal
D. Sine wave

Answer: B

9. If the maximum DC current rating of diodes in Bridge Rectifier is 1A, what is the maximum DC load current?
A. 1A
B. 2A
C. 4A
D. 8A

Answer: B

10. Voltage multipliers produce
A. Low voltage and low current
B. Low voltage and high current
C. High voltage and low current
D. High voltage and high current

Answer: C

Question And Answers 

11. What is a Clipper?
Answer: A circuit that removes a part (positive or negative) of a waveform so that it doesn’t exceed a certain voltage level.

12. What is a Clamper?
Answer: A circuit that adds a DC voltage (positive or negative) to a wave.

13. Zener diode can be described as
A. A rectifier diode.
B. A device with constant – voltage.
C. A device with constant – current.
D. A device that works in the forward region.

Answer: B

14. If the Zener Diode is connected in wrong polarity, the voltage across the load is
A. 0.7 V
B. 10 V
C. 14 V
D. 18 V

Answer: A 

Basic Transistor Questions

1. Number of PN Junctions in a Transistor 
A. One
B. Two
C. Three
D. Four

Answer: B

2. The doping concentration of Base in NPN Transistor is 
A. Lightly Doped 
B. Moderately Doped 
C. Heavily Doped 
D. Not Doped 
Answer: A

3. The Base – Emitter Diode (Base – Emitter Junction) in an NPN Transistor is 
A. Doesn’t conduct 
B. Forward Biased 
C. Reverse Biased 
D. Operates in breakdown region 

Answer: B

4. The size comparison between Base, Emitter and Collector is 
A. Base > Collector > Emitter 
B. Emitter > Collector > Base 
C. Collector > Emitter > Base 
D. All are equal 

Answer: C

5. The Base – Collector Diode (Base Collector Junction) is usually 
A. Reverse Biased
B. Forward Biased 
C. Breakdown Region 
D. No Conduction 

Answer: A

6. The DC Current Gain of a Transistor is 
A. Ratio of Emitter Current to Collector Current 
B. Ratio of Base Current to Emitter Current 
C. Ratio of Collector Current to Base Current D. Ratio of Base Current to Collector Current 

Answer: C

7. If base current is 100µA and current gain is 100, then collector current is 
A. 1A 
B. 10A 
C. 1mA 
D. 10mA 

Answer: D

8. The majority carriers in NPN and PNP Transistors are 
A. Holes and Electrons 
B. Electrons and Holes 
C. Acceptor Ions and Donor Ions 
D. None 

Answer: B

9. A Transistor acts as a 
A. Voltage Source and a Current Source 
B. Current Source and a Resistor 
C. Diode and Current Source 
D. Diode and Power Supply 

Answer: C

10. The relation between Base Current IB, Emitter Current IE and Collector Current IC is 
A. IE = IB + IC 
B. IB = IC + IE 
C. IE = IB – IC 
D. IC = IB + IE 

Answer: A

11. The total power dissipated by a transistor is a product of collector current and 
A. Supply Voltage 
B. 0.7V 
C. Collector – Emitter Voltage 
D. Base – Emitter Voltage 

Answer: C

12. The input impedance of Common Emitter Configuration is 
A. Low 
B. High 
C. Zero 
D. Very High 

Answer: A

13. The output impedance of Common Emitter Configuration is 
A. Low 
B. Very Low 
C. High 
D. Zero 

Answer: C

14. The current gain in Common Base configuration (α) is 
A. Ratio of Base Current to Emitter Current (IB/IE)
B. Ratio of Collector Current to Emitter Current (IC/IE)
C. Ratio of Collector Current to Base Current (IC/IB)
D. None 

Answer: B

15. Relation between α and ß is 
A. α = ß / (ß + 1) 
B. ß = α / (1 – α) 
C. α = ß * (ß + 1) 
D. α = ß / (ß – 1) 

Answer: Both A and B