Electrical engineers are people who design and create electrical systems and machines to make humans life easier. If you are going for a job interview as an electrical engineer, it’s important to get ready for some of the most asked electrical interview questions.
Here are 30 important electrical engineering interview questions and answers. They will increase your knowledge of the subject and help you prepare for an upcoming electrical engineering interview.
Basic Electrical Interview Questions
1: Define the term electrical engineering?
Electrical engineering is a concept based on the physics of mechanics. It involves the application and learning of electromagnetism and electricity in various appliances.
This is one of the most common questions asked in electrical interviews. Essential concepts often included in electrical engineering are A.C. & D.C. current, electric traction, transformers, etc.
2: State the meaning of the term “capacitance”.
The term capacitance refers to the charge (in coulomb) that can be stored inside a capacitor, at a given voltage.
3: State the meaning of the term “Inductance”
Inductance refers to a coil’s ability to oppose changes in the electric current flowing through it. For example, there is mutual inductance in two coils when the circuit’s secondary coil opposes the current change within the primary coil.
4: Define Ohm’s law.
Ohm’s Law is a fundamental principle in electrical engineering that describes the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit. The electric current in a circuit is directly proportional to voltage and inversely proportional to the resistance.
5: What is an electric shock?
An electric shock is caused when there is a flow of electrons through the human body.
6. What are the fundamental components of an electrical circuit?
Answer: The fundamental components of an electrical circuit include:
- Resistors: Limit current flow and divide voltages.
- Capacitors: Store electrical energy temporarily.
- Inductors: Store energy in a magnetic field when current flows through them.
- Diodes: Allow current to flow in one direction only.
- Transistors: Act as switches or amplifiers in circuits.
7: Define the principle of electromagnetic induction.
According to Faraday’s Law, a changing magnetic field induces an electromotive force (EMF) in a conductor.
8: Define Kirchhoff’s Current Law (KCL) and Voltage Law (KVL).
KCL states that the total current entering a junction equals the total current leaving it. KVL states that the voltages around a closed loop is zero.
9: What is the purpose of a transformer?
A transformer transfers electrical energy between circuits via electromagnetic induction, stepping voltage up or down based on need.
10: What will resistances connected to a voltage source in series do?
If the resistors are connected in a series circuit, the current flowing through each resistor remains constant, while the voltage splits.
11: What happens when two negatively charged substances are placed together?
According to the law of electric charges, two like charges placed in close proximity will always repel each other.
12: Define the frantic effect?
The frantic effect Is when the voltage received exceeds the input voltage in a given circuit.
13: What is Power Factor?
Power factor measures how effectively electrical power is used. It’s the ratio of real power to apparent power.
14: Why the capacitors work only on AC.
This is because capacitors usually provide infinite resistance to direct current.
15. What are semiconductors, and why are they critical in electronics?
Semiconductors, like silicon, have conductivity between that of conductors and insulators, making them essential in diodes, transistors, and integrated circuits.
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Intermediate Electrical Interview Questions and Answers
16. What is an alternating current (AC) generator, and how does it work?
An AC generator converts mechanical energy into electrical energy using electromagnetic induction. As the rotor spins, it induces an alternating voltage in the stator winding.
17: State the similarity between a generator and an alternator.
The generator and alternator have the same purpose – converting mechanical energy into electrical energy.
18: Explain what different colours in transmission line wires indicate.
For this electrical interview question, you could say there are five colours of wires available in transmission lines –
- Black wire: This wire is used to indicate power supply in any circuit. Any circuit with this colour wire is considered live/hot.
- Red wire: This is another live wire for circuits (With up to 220 volts). A red wire can either be connected to another red wire or to a black wire in a live circuit.
- Blue & Yellow wire: These wires also live wires but they are used as the live wire pulled through the conductor.
- White & Grey wire: These wires are often used as neutral wires. They carry current back to the surface of the Earth (for grounding purposes).
- Green wire: These wires are connected to the grounding terminals.
19: What type of fire – extinguisher is used to put out a fire caused by electrical wires?
Carbon Tetra-Chloride fire extinguishers are used to extinguish fires caused by electricity conduction.
20: What is the process of creating electricity in a thermal power station?
This is an important electrical interview question.
A thermal power station uses water boiled in large boilers (using coal) to create steam. This high-pressure steam is then used to rotate large turbines, leading to mechanical energy production. This mechanical energy is then converted to electrical power through generators and is then stored in batteries for further use.
21: What is a high-voltage direct current (HVDC) transmission system?
HVDC transmission systems transport electrical power over long distances with reduced losses compared to AC systems.
22: What happens to the resistance of a series circuit if the current is reduced by half?
If the current in a series circuit is reduced by ½, then the resistance doubles.
23: What is an Encoder?
An encoder is a device used to change a signal or data point into a functionable code.
24: What does an ACSR Cable do and where can we use it?
An aluminium conductor steel reinforced (ASCR) is used in the transmission and distribution of current. These wires are used in overhead transmission lines.
25: List three advantages of using ACSR cables in overhead transmission lines?
ACSR cables are advantageous for overhead transmission lines because of their good conductivity, low weight, and low cost.
Advanced Electrical Interview Questions
26: What is a Zener diode, and how does it work?
A Zener diode is a semiconductor diode that allows current to flow in both directions but primarily operates in reverse bias mode to maintain a stable output voltage.
27: Define the principle of motors.
The principle of an electric motor is situated on a conductor that carries current and produces a magnetic field surrounding it. The placement of a conductor perpendicular to a magnetic field leads to rotatory movements (known as torque).
28: What is Electromagnetic Interference (EMI)? How can it be mitigated?
EMI is unwanted noise or interference caused by electromagnetic radiation that affects the performance of electrical circuits and devices. It can mitigated using shielding, grounding, and filtering techniques.
29: What precautions should one take before replacing a fuse?
Before replacing a fuse, the main power source should be switched off.
30: How does a thyristor function in controlling power?
A thyristor is a semiconductor device that acts as a switch; it can control large amounts of power by turning on or off based on gate signals.
31: What precautions should be followed before removing the main switch?
Ensure that nobody is working on the corresponding transmission lines.
32: How do you determine the appropriate wire size for electrical installations?
Wire size is determined based on several factors:
- Current capacity (ampacity): Each wire gauge can safely handle a specific amount of current.
- Voltage drop: For long runs, minimising voltage drop is crucial to ensure efficiency.
- Type of insulation: Different insulation types have varying temperature ratings.
33: Elucidate the full form of the acronym S.W.G.
The acronym S.W.G stands for standard wire gauge.
34: What is the role of a voltage regulator?
A voltage regulator maintains a constant output voltage regardless of changes in input voltage or load conditions, ensuring stable operation of electronic devices
35: What is the difference between 4 –point starter and 3 –point starter?
This is the most frequently asked electrical interview question. The difference between a three-point starter connection and a four–point starter connection is the NVC. The NVC in a three-point starter system is connected in series to the circuit. However, in a four–point starter system, the NVC is directly attached to the primary voltage supply.
36: List the two types of DC generators that exist.
Direct current generators are categorized into two types: self–excited DC generators and separately excited DC generators.
37: Explain the principles on which a circuit breaker works.
A circuit breaker acts as a switch, which can be used to cut off the flow of current directly. The protective layers (indicators) indicate circuit breakage due to overloading or other issues, which then prevents the circuit from breaking.
38: Explain the meaning and role of an exciter.
An exciter is a device (a generator/batter) that supplies electric current to another generator or motor. This electric current is then used to produce the magnetic field in the other circuit.
39: What causes transformer losses?
Copper losses occur due to resistance in windings, and core losses are caused by hysteresis and eddy currents.
40: What is regenerative braking in electric motors?
Regenerative braking recovers kinetic energy from a moving motor and converts it back into electrical energy, improving efficiency.
Also Read: Basic Embedded Systems Interview Questions
Key Takeaways on Electrical Interview Questions
So, look no further if you are looking to gather basic electrical engineering knowledge or brush up on some electrical interview questions for your future interviews.
By skimming the list of electrical engineering interview questions and answers, you can ensure that you are prepared for your next interview.
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