Most Asked Electrical Engineering Interview Questions
Following is the list of most frequently asked Electrical Engineering Interview questions and their best possible answers.
Basic Interview Questions
1) What do you understand by the term electrical engineering? What are its different applications?
Electrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics, and electromagnetism. Electrical engineering generally deals with high voltage, especially AC above the range of 110 or 220V. Electrical machines, components, and devices use alternating current (AC) / Voltages and tend to be larger and require 230V (In UK) and 110V (In the US) single-phase ac voltages. In industries and power stations, it may require up to 11kV, and for transmission, it may be higher than 400kV.
The different applications of electrical engineering are as follows:
- Electrical Power Systems
- Electrical Control Systems
- Diodes, Rectifiers, and Transformers
- Digital Circuits
- AC and DC Motors
- AC and DC Generators
- Instrumentation Systems
- Communication Systems
- Digital and Analog Electronics etc.
2) What are the primary responsibilities of an electrical engineer?
The primary responsibilities of an electrical engineer are to create, design, test, and observe the electrical components of a project. This is a vast field, and projects within this field can vary from manufacturing products to designing power grids. Due to its vast field, the responsibilities can vary from position to position.
The key responsibilities of an electrical engineer are as follows:
- Fixing and troubleshooting electronic devices.
- Conducting the functionality tests.
- Analyzing current trends and information.
- Developing manufacturing processes for building and assembling electrical components etc.
3) What are the critical skills required to become an electrical engineer?
The main task of an electrical engineer is to take care of the components of the electrical system. To prevent and troubleshoot such failures, a skilled electrical engineer must do the following things:
- Analyze data to get top trends.
- Communicate clearly with supervisors and clients to get the decision efficiently.
- Keep up to date on emerging trends within the industry.
- Adhere to strict safety codes.
- Work in tandem with supervisors and management.
4) Why did you decide to become an electrical engineer? / What made you want to study electrical engineering?
The interviewers ask this question to check your passion for this engineering field, better understand your background, and figure out how they relate to each other. This is one of the primary and most asked electrical engineering interview questions. While answering this question, you should be ready to talk about your education, interest in engineering, and personal experiences in this field. Highlight your passion for the electrical engineering field and strictly avoid answers such as, “I knew engineers made good money” or “My parents wanted me to study electrical engineering.”
Technical Interview Questions
5) What are the fundamental components of electrical circuits?
Following are the fundamental components of electrical circuits:
- Active Circuits: Active Circuits are the elements used to generate energy from within their system as a form of source.
- Passive Circuits: Passive circuits are the elements that allow the electric current to pass through it and do not generate any energy from it.
- AC or DC Circuits: AC stands for Alternating Current, and DC stands for Direct Current. AC always produces some fluctuating current, whereas DC always produces a stable current in a constant source.
- Series Circuits: When the electrical components are connected in series within a circuit, it is known as a series circuit.
- Parallel Circuits: When the electrical components are connected in parallel within a circuit, it is known as a parallel circuit.
6) What is the difference between the term Capacitance and Inductance?
Difference between Capacitance and Inductance:
- Capacitance: The term capacitance can be specified as an amount of charge stored inside a capacitor at a specifically given voltage.
- Inductance: Inductance is the property of a coil to resist any changes in the electric current flowing through it. Mutual inductance happens when a secondary coil opposes the current change in the primary coil.
7) What would happen when two positively charged materials are placed together?
As we know that the positives repel and opposites attract. So, if you place two positively charged materials next to each other, the two materials will repel and move away.
8) What are the three different types of cables used in transmissions?
Following are the three different types of cables used in electric transmission:
- Low Tension Wire: It is used to transmit electricity upto 1000 volts.
- High Tension Wire: It is used to transmit electricity upto 23000 volts.
- Super Tension Wire: It is used to transmit electricity upto 132 kV.
9) What is the difference between a Capacitor, Resistor, and Inductor?
Capacitor: A capacitor is an electrical component that opposes the current flow and acts as a passive element. It also stores some form of electrical charge when a potential is applied.
- Resistor: A resistor is an electrical component that opposes the flow of current. It is a two-terminal component and is mainly used to reduce the flow of current.
- Inductor: An inductor is an electrical component used to build electrical circuits and store the energy in the form of a magnetic field. It is also called a choke or a coil.
10) What is the definition of an ideal transformer?
A transformer is called an ideal transformer if there no losses happen at all. In other words, we can say that, in an ideal transformer, the transformer input authority should be equivalent to the output authority of the transformer, i.e., they have 100% competence.
Note: An ideal transformer is a fantasy transformer or just a hypothetical transformer because there must be some losses in a genuine transformer.
11) What do you understand by reverse polarity? What is the process of fixing it?
Reverse polarity is a condition that occurs when the wires are incorrectly placed. For example, if the white wire connects to the hot side and the black wire connects to the neutral side. You can fix this problem by checking the connection of the wire from the outlet or checking the receptacle. You can solve the reverse polarity by swapping this entanglement.
12) What are the different types of networks used to build an electrical circuit?
There are mainly two types of networks used to build an electrical circuit called Passive or Active Networks. A Passive network is a network that contains passive elements in its network, such as Resistance, Capacitance, or Inductance. On the other hand, an Active Network is a network that contains active elements in its network, such as Current or Voltage Sources.
13) How a tube light circuit is connected, and how does it work?
In a tube light circuit, a choke is linked to one end of the tube light, and a starter is in sequence with the circuit. When we supply the current, the starter breaks off the supply cycle of AC. Due to this unexpected change in supply, the chock makes around 1000 volts. This voltage is enough to break the electrons within the tube to make the electrons flow. Once the accessible voltage passes through the pipe, the appetizer circuit will be out of the part. Now, no supply transform makes the choke voltage normal and diminishes the current.
14) What are the functions of the different colored wires in the electric circuit?
In the electric circuit, the different types of colored wires specify the different functions they do. Primarily, there are seven types of colored wires in the electric circuit that have their task.
- Black: The black wire is the primary source of power supply in the electric circuit. This is not used for ground wires. It is either used in the hot state or live state.
- Green: The green wire is used to connect to the ground terminal. An outlet box contains green wires.
- Red: The red wire is the second primary wire. It is used to transmit the live state of the wire. It can be used in different types of interconnections and are present in a circuit of 220 volts. Moreover, it can either be connected to another red wire or a black wire.
- White/Gray: The white or gray wire is the neutral wire. It is used to carry out the unbalanced load to the terminal. The terminal of this wire is located in the ground. This wire can connect itself to its types of wires.
- Blue/Yellow: The blue or yellow wires carry power, so they are used as live wires. Generally, most devices do not have these wires.
15) What are the main advantages of speed control using thyristor?
Following are some main advantages of speed control using thyristor:
- It reduces the cost.
- It is highly accurate.
- It provides fast switching characteristics than BJT and IGBT.
16) What are the transistors made of?
The transistors are made of several combinations of n-type and p-type semiconductors.
17) What are some essential tools used for the measurement of electrical parameters in an electrical circuit?
Following is the list of some measuring tools used for the measurement of electrical parameters:
- Voltmeter
- Ammeter
- Ohmmeter
- Multi-meter
- Power meter
- Microwave meter
- Cathode Ray Oscilloscope
- Signal Generators and Analyzers
- Wattmeter
- Sweep Generator etc.
18) What is Armature Reaction?
The armature reaction is the effect of the armature field on the main field. In other words, we can say that the armature reaction specifies the impact of the armature flux on the main field flux. The armature field is produced by the armature conductors when we flow the current through them.
19) What are the different criteria you should keep in mind while selecting a type of wire?
We should select the wire based on several factors such as wire capacity, a gauge of the different wires, etc. If you use larger and heavier products, such as electrical heaters or furnaces, you should choose a smaller wire gauge. Gauge 6 wire may be perfect for this purpose. It has a higher capacity to carry and handle the current. On the other hand, if you choose the wire for household objects such as lamps and lights, which require a low voltage, you should choose the wires with higher gauge values. Gauge 12 wire may be perfect for this purpose.
20) What are the different types of coupling mechanisms in an electric circuit?
There are mainly three different types of coupling mechanisms used in an electric circuit:
- Conductive Coupling: In conductive coupling, we have to give the power supply simultaneously to both the sensor and the load.
- Inductive Coupling: In Inductive coupling, an electric field is a leading cause for the noise.
- Capacitive Coupling: In Capacitive coupling, a magnetic field is a leading cause of the current flows’ noise.
21) What do you understand by ASCR cable, and where is it used?
ACSR cable stands for Aluminum Conductor Steel-Reinforced cable. It is a type of high-capacity, high-strength stranded conductor wire typically used in overhead power lines. It is also used in broadcast & distribution. It is best suited for broadcast & distribution because of its good conductivity, low weight, low cost, resistance to corrosion, and decent mechanical stress resistance.
22) What is the Control System, and what are its different types?
A Control System is a system where the output and inputs are interrelated so that the input parameters control the output parameters. There are mainly two types of Control Systems, i.e., Open-loop Control systems and Closed Loop Control Systems.
- Open-loop Control System: In Open-Loop Control Systems, there is no feedback from the output-input for correction.
- Closed-Loop Control Systems: In Closed Loop Control Systems, there is feedback from the output to input for correction to control the desired output quantities.
23) What do you understand by the RLC current?
RLC stands for Resistor (R), Inductor (which is denoted by L), and Current (C). The word RLC is made of three elements of the circuit which are Resistor (R), Inductor (L), and Current (C). This circuit can provide direct current flowing throughout the circuit. This ability is characterized by a differential equation of the second order. That’s why it is also known as a second-order circuit.
24) What is a transformer and what are its applications?
A Transformer is an electrical device used to convert the electric voltage from smaller to larger quantities and vice versa. In other words, we can say that a transformer is a device that transfers electric energy from one alternating-current circuit to one or more other circuits. It is either used to increase (step-up) or reduce (step down) the voltage.
Following are the main applications of a transformer:
- The main task of a transformer is to step up or step down voltages.
- A transformer can be used to match impedance.
- It can be used as a rectifier.
- It acts as a voltage rectifier or stabilizer also.
- It is also used in voltmeter or ammeter applications.
- It is also used for the isolation of electrical circuits.
25) What do you understand by Alternator and Generator? What are the main differences between them?
The Alternator and Generator are both used for power generation. An Alternator generates the power on a small scale, whereas the Generator generates electricity by converting one form of energy to another.
Following is a list of main differences between an Alternator and a Generator:
| Alternator | Generator |
|---|---|
| An Alternator is used to generate power on the small-scale requirement. | A Generator is used to generate electricity for large-scale requirements or supplies. |
| In Alternator, electricity is produced by spinning the magnetic field inside the windings of the copper wire. | A generator uses dynamo to convert mechanical energy to electrical energy. It works on the principle of electromagnetic induction. |
| Alternators use only the required amount of energy. So, they conserve more energy. | Generators use all the energy that is produced. So, they conserve less energy. |
| An alternator always induces an alternating current (AC). | A generator can generate either alternating (AC) or direct current (DC). |
| Alternators are considered very efficient. | Generators are considered less efficient. |
| It doesn’t require polarization in the case of alternators. | Polarization is required after installation in the case of generators. |
| In Alternator, the magnetic field is rotating inside the stator. | In Generator, the magnetic field is stationary or fixed, and the armature winding spins. |
| The armature of an alternator is always stationary. | The armature of the Generator is rotating. |
| The Alternator receives the input supply from the stator. | The Generator receives the input supply from the rotor. |
| Alternators generate voltage only when needed. | Generators produce voltage at all times. |
| Alternators run on a high range of RPM. | Generators run on a high range of RPM. |
| Alternators are generally smaller in size. | Generators are generally larger and require more space to fit in. |
| Alternators can never charge a dead battery. | A generator can be used to charge a dead battery. |
| The brushes of alternators are long-lasting. | The brushes of generators are lesser long-lasting when compared to an alternator. |
| Alternators are mainly used in the automobile industry as a charging system for the battery. | Generators are mainly used to produce large-scale electricity. |
26) What would happen if the series current gets double?
If the series current gets double, then the confrontation will half.
27) What are the different types of semiconductors?
There are mainly two types of semiconductors used in electronics, i.e., intrinsic and extrinsic semiconductors. The extrinsic semiconductors can be categorized into N-type semiconductors and P-type semiconductors.
28) What do you understand by a Zener diode?
A Zener diode is a specific type of semiconductor diode used to permit existing current to flow in the conflicting direction when uncovered to sufficient voltage.
29) What is the primary usage of a transistor in an electric circuit?
Transistors are mainly used to amplify the current to make the output power higher than the input power.
30) What is the usage of a string of resistors in a series?
When we add a string of resistors in a sequence, they split the source voltage into the amount to their values.
31) How the NPN and PNP transistor works?
When we use NPN transistor in a circuit:
When we use PNP transistor in a circuit:
32) What do you understand by a laser diode?
A laser diode is a compact transistor with two or even more than two electrical leads. It is a semiconductor device similar to a light-emitting diode in which a diode-pumped directly with an electrical current can create lasing conditions at the diode’s junction. Laser diodes can directly convert electrical energy into light.
33) What do you understand by reverse polarity, and how can you fix it?
The reverse polarity is a condition where one or more receptacles are misconnected. You should check the wire connection at the outlet and inspect the receptacle to fix the reverse polarity. A receptacle with reverse polarity connects the white wire to the hot side and the black wire to the neutral side. You can swap the wires to resolve the problem efficiently.
34) What is the full form of FPGA, and why is it used?
The full form of the term FPGA stands for Field Programmable Gate Array. It is one type of semiconductor logic chip programmed to become almost any kind of system or digital circuit such as PLDs. The only difference between PLD and FPGA is that PLDS are limited to hundreds of gates, but FPGAs support thousands of gates. The FPGA architecture’s configuration is generally specified using a language known as HDL (Hardware Description language).
35) What do you understand by a two-phase motor?
A two-phase motor is an electrical system (motor) with two voltages 90 degrees apart. The alternator is composed of two windings placed at 90 degrees from each other. They require two live and one ground wire that works in two phases. These types of motor are no longer in use nowadays.
36) What is a rectifier and what are its different types?
A rectifier is an electrical device used to convert alternating current into direct current. The current inside a rectifier flows in a single direction.
The two different types of rectifiers are:
- Half-wave rectifier: The half-wave rectifier is a type of rectifier that has only a single PN junction.
- Full-wave rectifier: The full-wave rectifier is a type of rectifier that has two PN junctions.
37) What are the main differences between an Analogue and a Digital circuit?
Differences between an Analogue and a Digital circuit:
| Analogue Circuit | Digital Circuit |
|---|---|
| The Analogue circuits operate on continuous-valued signals. | The Digital circuits operate on the signal, which exists at two levels 0’s and 1’s. |
| This circuit doesn’t require conversion of the input signal before transmitting the signals. This circuit directly executes various logical operations and produces an analog output. | This circuit requires the conversion of the input signal before transmitting the signals. Before the signal is transmitted, it is converted into digital form. |
| This circuit is more precise because there is no probability of losing any information as there is no conversion. | This circuit is less precise because, during signal conversion, some amount of information can be lost. |
| The Analogue circuit lacks flexibility. | The Digital circuits provide a high range of flexibility to offer to its users. |
38) What do you understand by a transistor?
A transistor is a semiconducting device that is made up of semiconducting materials. Transistors are used to interpret electrical signals and powers. A transistor should be connected to at least three terminals through an external circuit. It is also known as a combination of many n-type and p-type semiconductors.
39) What are the main usages of a transistor?
The primary usage of a transistor is to increase the input current, which ultimately increases the output. In other words, we can say that transistors are used to increase electric and electrical power.
40) What do you understand by AVR or automatic voltage regulator?
AVR is a short-term that stands for Automatic Voltage Regulator. It is a central part of Synchronous Generators and is used to regulate the voltage. It gets the fluctuation in the voltage and changes them into a constant voltage. The fluctuation in the voltage generally occurs due to the variation in load on the supply system, which can damage the equipment of the power system. To control the voltage, we have to install the voltage control equipment at several places such as near the transformers, generator, feeders, etc.
41) What is SF6 gas? Why is it used?
SF6 gas is known as Sulphur Hexafluoride gas. This gas is used to extinguish the arc because it is an excellent dielectric, arc quenching, and has chemical and other physical properties, making it superior to other arc quenching mediums such as oil or air. Due to this reason, it is called a circuit breaker. The SF6 circuit breaker is mainly divided into three types:
- Non-puffer piston circuit breaker.
- Single-puffer piston circuit breaker.
- Double-puffer piston circuit breaker.
42) Why is SF6 gas used in circuit breakers?
The SF6 gas is used in circuit breakers due to its low gaseous viscosity. The SF6 gas can efficiently transfer heat by convection. Due to this unique property, the SF6 gas is used as a circuit breaker in a complete range of medium voltage and high voltage electrical power systems.