Showing posts with label Analog Electronics. Show all posts

May 8, 2026

Most Asked Interview Questions Series for Electronics and VLSI Engineers

Preparing for electronics and VLSI interviews can feel overwhelming because of the vast number of technical subjects involved. From Digital Electronics and Verilog to FPGA, Analog Electronics, and Semiconductor concepts, students are expected to have strong fundamentals across multiple domains.

To help students prepare effectively, we are starting a complete Most Asked Interview Questions Series covering the most important and frequently asked topics in Electronics Engineering, VLSI, FPGA, Embedded Systems, and Semiconductor technology.

This series is designed for:

Electronics Engineering Students
VLSI and FPGA Beginners
Campus Placement Preparation
Technical Interview Preparation
Viva Examinations
Internship Preparation
GATE and Competitive Exam Revision

📚 Interview Questions Series

Why This Series?

Most interview preparation resources provide only theoretical definitions without proper conceptual understanding. This series focuses on concise, interview-oriented explanations that help students quickly revise important concepts while also understanding the fundamentals behind them.

Each blog in this series is designed to cover the most commonly asked questions from a specific subject or topic area to help students prepare smarter and more efficiently.

Conclusion

Whether you are preparing for campus placements, VLSI interviews, FPGA roles, embedded systems positions, or university viva examinations, strong technical fundamentals are extremely important.

This interview questions series will continue expanding with more electronics, semiconductor, embedded systems, and VLSI-related topics to help students build strong technical knowledge and interview confidence.

Happy Learning! 🚀

Most Asked Electronics Interview Questions

Most Asked Electronics Engineering Interview Questions

Electronics Engineering is one of the most important branches of engineering and covers subjects such as analog electronics, digital electronics, communication systems, embedded systems, microprocessors, VLSI, and semiconductor technology.

Questions from electronics engineering are commonly asked in technical interviews, campus placements, viva examinations, and competitive exams. In this blog, we will cover some of the most frequently asked Electronics Engineering interview questions along with concise and interview-oriented answers.

1. What is Electronics Engineering?

Electronics Engineering is a branch of engineering that deals with the design, development, and application of electronic devices, circuits, communication systems, and embedded systems.

2. What is the difference between Electrical and Electronics Engineering?

Electrical Engineering	Electronics Engineering
Deals with high voltage and power systems	Deals with low voltage electronic circuits
Focuses on power generation and transmission	Focuses on signal processing and communication
Used in power plants and industries	Used in computers, communication, and embedded systems

3. What is a Semiconductor?

A semiconductor is a material whose electrical conductivity lies between that of a conductor and an insulator. Silicon and germanium are commonly used semiconductor materials.

4. What is the difference between Analog and Digital Electronics?

Analog Electronics	Digital Electronics
Works with continuous signals	Works with discrete binary signals
More sensitive to noise	Less sensitive to noise
Used in audio and RF systems	Used in computers and digital systems

5. What is a Diode?

A diode is a semiconductor device that allows current to flow mainly in one direction. It is widely used in rectifiers, clipping circuits, and voltage regulation applications.

6. What is a Transistor?

A transistor is a semiconductor device used for amplification and switching applications. The two main transistor types are BJT and MOSFET.

7. What is an OPAMP?

An Operational Amplifier or OPAMP is a high-gain differential amplifier with high input impedance and low output impedance. It is widely used in amplification, filtering, and signal conditioning circuits.

8. What is a Logic Gate?

A logic gate is a digital circuit that performs logical operations on binary inputs to generate a binary output. Common logic gates include AND, OR, NOT, NAND, NOR, XOR, and XNOR.

9. What is a Flip-Flop?

A Flip-Flop is a bistable sequential circuit used to store one bit of binary data. It is widely used in counters, registers, and memory systems.

10. What is a Microprocessor?

A microprocessor is a programmable integrated circuit that performs arithmetic, logical, and control operations. It acts as the central processing unit (CPU) of a computer system.

11. What is a Microcontroller?

A microcontroller is a compact integrated circuit that contains a processor, memory, and input/output peripherals on a single chip. It is widely used in embedded systems and automation applications.

12. What is VLSI?

VLSI stands for Very Large Scale Integration. It is the process of integrating millions of transistors onto a single chip to design complex integrated circuits such as processors and memory devices.

13. What is FPGA?

FPGA stands for Field Programmable Gate Array. It is a programmable integrated circuit that can be configured after manufacturing to implement digital hardware designs.

14. What is Communication System?

A communication system is a system used to transfer information from a transmitter to a receiver through a communication channel such as wire, optical fiber, or wireless medium.

15. What is Embedded System?

An embedded system is a specialized computer system designed to perform dedicated functions within a larger electronic system. It combines hardware and software to perform specific tasks.

Conclusion

Electronics Engineering combines concepts from analog electronics, digital systems, semiconductor devices, communication systems, embedded systems, and VLSI technology. Strong fundamentals in these areas are essential for technical interviews and engineering careers.

Regular revision and clear conceptual understanding can help students confidently answer interview questions and build strong technical foundations.

Happy Learning! 🚀

Most Asked Analog Electronics Interview Questions

Analog Electronics is one of the core subjects in electronics engineering and forms the foundation for amplifiers, communication systems, signal processing, and mixed-signal circuit design.

Questions from analog electronics are commonly asked in interviews for electronics, embedded systems, VLSI, and core engineering roles. In this blog, we will cover some of the most frequently asked Analog Electronics interview questions along with concise and interview-oriented answers.

1. What is Analog Electronics?

Analog Electronics deals with continuous-time signals whose values vary continuously with time. It involves circuits such as amplifiers, filters, oscillators, and transistor-based analog systems.

2. What is the difference between Analog and Digital Signals?

Analog Signal	Digital Signal
Continuous in nature	Discrete in nature
Infinite values possible	Limited binary values
More sensitive to noise	Less sensitive to noise

3. What is an Amplifier?

An amplifier is an electronic circuit that increases the amplitude of a weak input signal without significantly changing its waveform. Amplifiers are widely used in audio systems, communication systems, and signal processing circuits.

4. What is gain in an amplifier?

Gain is the ratio of output signal amplitude to input signal amplitude. It indicates how much the amplifier increases the signal strength.

5. What is a transistor?

A transistor is a semiconductor device used for amplification and switching applications. The two main types of transistors are Bipolar Junction Transistor (BJT) and Metal Oxide Semiconductor Field Effect Transistor (MOSFET).

6. What is the difference between BJT and MOSFET?

BJT	MOSFET
Current controlled device	Voltage controlled device
Higher switching losses	Lower switching losses
Lower input impedance	Higher input impedance

7. What is an Operational Amplifier (OPAMP)?

An Operational Amplifier or OPAMP is a high-gain differential amplifier with very high input impedance and low output impedance. It is widely used in analog circuits for amplification, filtering, integration, and signal conditioning.

8. What is virtual ground in an OPAMP?

Virtual ground is a condition in an ideal OPAMP where the voltage difference between the inverting and non-inverting terminals becomes nearly zero due to negative feedback.

9. What is bandwidth?

Bandwidth is the range of frequencies over which a circuit or amplifier operates effectively without significant signal attenuation.

10. What is feedback in amplifiers?

Feedback is the process of feeding a portion of the output signal back to the input. Negative feedback improves stability, bandwidth, and linearity, while positive feedback is mainly used in oscillators.

11. What is an oscillator?

An oscillator is an electronic circuit that generates a continuous periodic waveform without requiring an external input signal. Oscillators are widely used in clocks, communication systems, and signal generators.

12. What is a filter?

A filter is a circuit used to allow certain frequency components to pass while attenuating unwanted frequencies.

Common types include low-pass, high-pass, band-pass, and band-stop filters.

13. What is slew rate in an OPAMP?

Slew rate is the maximum rate of change of the output voltage with respect to time in an OPAMP. It determines how quickly the amplifier can respond to rapid input signal changes.

14. What is impedance?

Impedance is the total opposition offered by a circuit to alternating current (AC). It includes both resistance and reactance components.

15. What are the applications of Analog Electronics?

Analog Electronics is used in audio amplifiers, communication systems, sensors, medical electronics, power supplies, radio-frequency circuits, and signal processing applications.

Conclusion

Analog Electronics is a fundamental subject for electronics engineers and is essential for understanding real-world electronic systems. Strong knowledge of amplifiers, OPAMPs, transistors, filters, and feedback systems is important for interviews, higher studies, and core electronics careers.

Building clear conceptual understanding along with practical circuit analysis skills can help students perform well in interviews and technical discussions.

Happy Learning! 🚀

February 3, 2026

Understanding Resonance in AC Circuits — When Reactances Cancel Out

In AC circuits, frequency plays a crucial role in deciding how current flows. At one special frequency, the effects of inductors and capacitors perfectly balance each other, leading to a powerful phenomenon called resonance.

In this blog, we’ll understand what resonance is, why it happens, and how it can be visualized using a practical RLC circuit simulation.

⚡ Resonance

Resonance in an AC circuit is the condition at which the inductive reactance (Xₗ) becomes equal to the capacitive reactance (X꜀), causing them to cancel each other out. At resonance, the circuit behaves purely resistive, and the current becomes maximum.

To understand resonance, you must understand impedance and reactance.

🔌 What Is Impedance?

In AC circuits, current and voltage change direction continuously.

So, opposition to current is not just resistance (R). There are two more components:

Inductive reactance (Xₗ) — comes from inductors
Capacitive reactance (X꜀) — comes from capacitors

The total opposition in an AC circuit is called Impedance (Z):

Z = \sqrt{R^{2} + (X_{L} - X_{C})^{2}}

Where:

$X_L = 2\pi f L$
$X_C = \frac{1}{2\pi f C}$

Notice something important:

Xₗ increases with frequency
X꜀ decreases with frequency

But there is one special frequency where their effects cancel each other.

🎯 Resonance Condition

Resonance occurs where capacitive reactance equals inductive reactance:

X_{L} = X_{C​}

Substitute the formulas:

2 π f_{0} L = \frac{1}{2 π f_{0} C​}

Solving for frequency:

f_0 = \frac{1}{2\pi\sqrt{LC}}

This frequency is called the resonant frequency.

🔍 What Happens at Resonance?

At the resonant frequency $f_{0}$ :

✔ Inductive reactance equals capacitive reactance

X_{L} - X_{C} = 0

✔ Impedance becomes minimum

Z = R

The circuit behaves as if it has only resistance.

✔ Current becomes maximum

I = \frac{V}{R​}

✔ Voltage magnification occurs in L and C

Even though the net reactive effect is zero, energy continuously transfers between the inductor and capacitor:

Inductor stores magnetic energy
Capacitor stores electric energy

They keep exchanging energy, creating large voltages inside the circuit.

🧪 LTspice Simulation of Resonance

To visualize this phenomenon, a series RLC circuit was simulated in LTspice using the following values:

R = 50 Ω
L = 45 mH = 0.045 H
C = 1.36 μF = 1.36 × 10⁻⁶ F
AC source = 230 V
AC sweep = 100 Hz to 2000 Hz

🔧 Circuit Explanation

The simulated circuit is a series RLC network.

All three components (R, L, and C) are connected one after another, and an AC source is applied across the combination.

The current through the resistor I(R1) is observed, which represents the current flowing through the entire series loop.

🧮 Resonant Frequency Calculation

Step 1: Multiply L and C

LC = 0.045 \times 1.36 \times 10^{-6}

LC = 6.12 \times 10^{-8}

Step 2: Square root of LC

\sqrt{LC} = \sqrt{6.12 \times 10^{-8}}

\sqrt{LC} = 2.472 \times 10^{-4}

Step 3: Multiply by $2\pi$

2\pi \times 2.472 \times 10^{-4}

2\pi \approx 6.283

2 π \sqrt{L C} = 0.001554

Step 4: Take reciprocal

f_0 = \frac{1}{0.001554}

f_0 \approx 643.7 \text{ Hz}

\boxed{f_0 \approx 644 \text{ Hz}}

📈 Verification from Simulation

At resonance:

$X_L = X_C$
Net reactance $X = 0$
Impedance $Z = R = 50 \Omega$

Current becomes:

I = \frac{V}{R} = \frac{230}{50} = 4.6 \text{ A}

The simulation peak current is very close to 4.5–4.7 A, confirming perfect resonance behavior.

🔚 Conclusion

Resonance is a powerful condition in AC circuits where inductive and capacitive reactances cancel each other, leaving only resistance to oppose current flow. At this point, impedance is minimum and current reaches its maximum value.

Although the net reactance becomes zero, energy continuously oscillates between the magnetic field of the inductor and the electric field of the capacitor, leading to voltage magnification within the circuit. This phenomenon is the foundation of tuned circuits, filters, oscillators, and communication systems.

Understanding resonance completes the journey from resistance → reactance → impedance and opens the door to advanced AC circuit analysis.

Understanding Impedance — The Total Opposition in AC Circuits

In AC circuits, opposition to current is not as simple as resistance alone. When resistors, inductors, and capacitors work together, both magnitude and phase come into play.

This combined effect is called impedance, and it defines how AC circuits truly behave.

⚡ Impedance — The Total Opposition

Now, let’s combine everything.

When resistors, inductors, and capacitors are all connected in an AC circuit, the total opposition to current is called Impedance (Z).

Impedance includes both:

Resistance (R) — which is constant and frequency-independent.
Reactance (X) — which depends on frequency and causes phase shift.

📐 Definition of Impedance (Phasor Form)

When working with AC signals, both voltage and current are sinusoidal and can be represented as phasors — rotating vectors showing both magnitude and phase.

The true definition of impedance is based on this phasor relationship:

Z = Ṽ / Ĩ

where:

Ṽ = voltage phasor (magnitude + phase)
Ĩ = current phasor (magnitude + phase)

Thus, impedance is a complex ratio that expresses both:

how strongly the circuit opposes current (magnitude), and
how voltage and current are shifted relative to each other (phase difference).

From this relationship:

|Z| = |Ṽ| / |Ĩ|
∠Z = ∠Ṽ − ∠Ĩ

This means:

The magnitude of impedance tells how much the circuit resists the flow of AC current.
The phase angle (∠Z) shows whether voltage leads or lags current, and by how much.

❗ Important Clarification

Impedance is not simply the ratio of instantaneous or RMS values:

❌ Z = Vₚₑₐₖ / Iₚₑₐₖ
❌ Z = v(t) / i(t) (instantaneous values)
❌ Z = Vᵣₘₛ / Iᵣₘₛ — unless both are treated as phasors including phase information

✅ The correct and complete definition is:

Z = Ṽ / Ĩ

This phasor ratio accounts for both magnitude and phase, which is why impedance is a complex quantity, expressed as:

Z = R + jX (rectangular form)
Z = |Z| ∠ θ (polar form)

🧮 Magnitude of Impedance

The magnitude of impedance is given by:

Z = √(R² + X²)

Here, X can be:

Positive → Inductive reactance (Xᴸ)
Negative → Capacitive reactance (−Xᶜ)

In phasor form, impedance is written as:

Z = R + jX

where:

j (or i) indicates a 90° phase shift

⚙️ Impedance of R, L, and C

Resistor:
Zᵣ = R (purely real, θ = 0°)
Inductor:
Zᴸ = jωL = j2πfL (purely imaginary, positive)
Capacitor:
Zᶜ = 1 / jωC = −j(1/ωC) (purely imaginary, negative)

So, for a circuit containing R, L, and C:

Net reactance: X = Xᴸ − Xᶜ
Total impedance: Z = R + j(Xᴸ − Xᶜ)

🎛️ Frequency Dependence

This is where the magic happens:

Inductors: Reactance increases with frequency
Capacitors: Reactance decreases with frequency
Resistors: Unaffected by frequency

Because of this:

Inductors and capacitors are frequency-dependent components
Resistors are frequency-independent

This frequency-dependent behavior forms the basis of filters, oscillators, and resonant circuits — the heart of modern electronics.

🔚 Conclusion

Impedance is the complete description of how an AC circuit opposes current flow. It combines resistance, which dissipates energy, with reactance, which stores and returns energy through electric and magnetic fields.

While resistance determines how much current flows, impedance also tells us how voltage and current are phase-shifted, revealing the true dynamic nature of AC circuits. Its dependence on frequency is what enables filtering, tuning, resonance, and signal shaping in electronic systems.

Understanding impedance is a major step forward in electronics — it connects resistance, reactance, frequency, and phase into one powerful concept that brings AC circuits fully to life.

Understanding Reactance — Opposition to Change in AC Circuits

When we first learn about circuits, resistance feels like the only opposition to current. But as soon as we move into AC circuits, where voltage and current are constantly changing, a new concept comes into play — reactance.

In this blog, we’ll explore what reactance is, why it exists, and how it shapes the behavior of capacitors and inductors in AC systems.

⚡ What is Reactance?

When we first learn about circuits, we meet resistance — the opposition that limits how much current flows. But the moment we move from DC (Direct Current) to AC (Alternating Current), the story becomes much more interesting.

Here, the voltage and current are continuously changing, and this change introduces a new kind of opposition called Reactance.

Let’s explore what it really is, why it matters, and how it connects to a concept called Impedance — the total opposition in AC circuits.

In simple terms, reactance is the opposition that a capacitor or inductor offers to the flow of alternating current (AC).

It’s similar to resistance but with a key difference:

Resistance opposes all current, whether AC or DC.
Reactance only opposes changing current — the kind that goes up and down, like in AC.

When voltage and current are constantly varying, capacitors and inductors react to that change.

Capacitors store energy in the electric field.
Inductors store energy in the magnetic field.

Unlike resistors, these components don’t waste energy as heat. They temporarily store energy and return it to the circuit. This storage and return create a delay in current or voltage, and that delay is what we call reactance.

🔧 Why is Reactance Needed?

In an AC system, voltage and current are not steady — they continuously rise, fall, and even reverse direction.

This constant change interacts with capacitors and inductors, which try to “resist” or “delay” the change due to how they store energy.

The inductor resists a change in current because it builds a magnetic field around itself.
The capacitor resists a change in voltage because it builds up an electric field between its plates.

This time-dependent opposition is exactly what allows us to design filters, amplifiers, and tuned circuits — all of which depend on reactance.

⚖️ Reactance vs. Resistance

So, we don’t use the same word “resistance” for both because:

Resistance dissipates energy as heat.
Reactance stores and gives back energy.

Their effects on current and voltage are fundamentally different.

🌀 Inductive Reactance — Opposition from a Coil

An inductor is simply a coil of wire that stores energy in a magnetic field when current passes through it.

But when you try to change that current, the inductor resists (thanks to Lenz’s Law).

The fundamental relation for an ideal inductor is:

V = L (dI/dt)

Where:

V = voltage across the inductor
L = inductance (Henry)
dI/dt = rate of change of current

This means the voltage depends on how quickly the current changes.

If the current changes fast, the voltage across the inductor becomes large.

Here’s what happens when AC is applied:

The inductor initially resists the change — it takes time to build a magnetic field.
The applied voltage goes into creating that magnetic field instead of immediately increasing current.
Once the current flows, it continues even as voltage starts to fall, because the inductor releases its stored energy.

This delay means current lags behind voltage by 90° in a pure inductor.

Inductive reactance is given by:

Xₗ = 2πfL

Where:

f = frequency (Hz)
L = inductance (H)

So, as frequency increases, inductive reactance also increases.

That’s why:

For DC (f = 0), Xₗ = 0 → acts like a short circuit.
For high-frequency AC, Xₗ becomes very large → acts like an open circuit.

🔵 Capacitive Reactance — Opposition from a Capacitor

For a capacitor, the voltage and current relationship is:

i(t) = C (dv/dt)

Where:

i(t) = current through the capacitor
v(t) = voltage across the capacitor
C = capacitance (Farad)

This equation shows that the current depends on how fast the voltage changes — not its actual value.

What really happens in AC:

As voltage begins to rise, charges start moving instantly — current begins flowing immediately.
It takes some time before enough charge accumulates for voltage to build up across the plates.
Hence, current reaches its peak first — when voltage is changing fastest.
Voltage reaches its maximum later — about a quarter cycle (90°) later.

Thus, current leads voltage by 90° in a pure capacitor.

Capacitive reactance is given by:

X꜀ = 1 / (2πfC)

So, as frequency increases, capacitive reactance decreases.

That’s why:

Capacitors pass high-frequency signals easily.
But they block DC (since f = 0 ⇒ X꜀ = ∞).

🔄 The Two Types of Reactance

If you observe closely, they’re complete opposites in nature:

In an inductor, voltage leads current.
In a capacitor, current leads voltage.
Inductive reactance increases with frequency, while capacitive reactance decreases.

When both are present in a circuit, their effects can even cancel each other out — a concept known as resonance.

🔚 Conclusion

Reactance is a fundamental concept that explains how inductors and capacitors behave in AC circuits. Unlike resistance, which simply dissipates energy, reactance arises because energy is temporarily stored and returned through magnetic and electric fields.

Inductive reactance opposes changes in current, while capacitive reactance opposes changes in voltage. Their frequency-dependent nature allows engineers to design filters, oscillators, tuned circuits, and frequency-selective systems.

Understanding reactance is a crucial step toward mastering AC circuit analysis and leads naturally into deeper topics like impedance, resonance, and AC power systems.

Understanding Inductors and Inductance — How Magnetic Energy Is Stored

In electronic circuits, not all components respond instantly to changes. Some store energy and react over time. One such fundamental component is the inductor, which stores energy in a magnetic field and resists changes in current.

In this blog, we’ll understand what an inductor is, how it works, how it stores energy, and what inductance really means.

⚙️ What is an Inductor?

An inductor is a passive electronic component that stores electrical energy in the form of a magnetic field.
It mainly opposes changes in current — just like a capacitor opposes changes in voltage.

Whenever current starts flowing through an inductor, it generates a magnetic field around it.
And when that current changes (increases or decreases), the magnetic field changes too — which in turn induces a voltage that tries to oppose that change.

That’s the fundamental nature of an inductor.

🧱 Structure — How It’s Made

An inductor is typically made of:

A coil of wire — usually copper, wound in loops or turns.
A core — which can be air, iron, or ferrite placed inside the coil to enhance its magnetic properties.
Two terminals / leads — for connection to the circuit.

The more turns the coil has, and the better the core material, the stronger the magnetic field it can create — and hence, the higher the inductance.

⚙️ How Does an Inductor Work?

Before any current flows:

There is no magnetic field around the coil.

When a voltage source is connected:

Current starts flowing through the wire coil.
As current flows, a magnetic field forms around the coil (according to Ampere’s Law).
If the current keeps increasing, the magnetic field grows — but this change in magnetic flux induces an opposing voltage (back EMF) in the coil (as per Faraday’s Law of Electromagnetic Induction).
This induced voltage always acts in the opposite direction of the applied voltage — this is Lenz’s Law in action.

So what’s happening inside is that the inductor resists any change in current.

If you try to increase current, it generates a voltage that opposes the increase.
If you try to decrease current, it generates a voltage that tries to keep it flowing.

💡 In Simple Words

Capacitor → opposes change in voltage
Inductor → opposes change in current

🔋 Energy Storage in an Inductor

An inductor stores energy in the magnetic field created by the current flowing through it.

The moment you disconnect the source, this magnetic field collapses and releases energy back into the circuit.

The energy stored is given by:

E = ½ L I²

where:

E = energy stored (joules)
L = inductance (henries, H)
I = current through the inductor (amperes)

Just like a capacitor stores energy in an electric field, an inductor stores it in a magnetic field.

🧮 What is Inductance?

Inductance is the ability of an inductor to store magnetic flux per unit current.

In simple terms, it tells how much magnetic field (or magnetic flux) an inductor can produce for a given current flowing through it.

It is denoted by L and measured in Henries (H).

Mathematically:

L = NΦ / I

where:

N = number of turns in the coil
Φ = magnetic flux linked with the coil (Weber)
I = current through the coil (amperes)

It basically tells us how much magnetic flux is produced for a given current.

⚡ Voltage–Current Relationship

The voltage across an inductor is given by:

V = L (dI/dt)

This means:

If the current changes rapidly, the induced voltage is large.
If the current is steady, dI/dt = 0, so the voltage across the inductor is zero.

Once fully energized with DC, an inductor behaves like a short circuit.

🧠 Factors Affecting Inductance

Number of Turns (N): More turns → higher inductance
Core Material: Iron or ferrite cores concentrate magnetic flux → higher inductance
Cross-sectional Area (A): Larger area → stronger field → higher inductance
Length of Coil (l): Longer coil → weaker field → lower inductance

For a solenoid:

L = (μ N² A) / l

where:

μ = permeability of the core material
N = number of turns
A = cross-sectional area
l = length of the coil

Here, μ (mu) plays a similar role as ε (epsilon) in capacitors — it tells how well the core supports the magnetic field.

🧩 Summary Table

🔚 Conclusion

An inductor is a fundamental passive component that stores energy in the form of a magnetic field and resists changes in current. By generating an opposing voltage whenever current changes, inductors play a critical role in controlling current flow in electronic circuits.

Inductance defines how effectively an inductor can store magnetic energy, and it depends on physical factors like the number of turns, core material, and coil geometry. Inductors are widely used in filters, power supplies, energy storage systems, and signal processing circuits.

Understanding inductors and inductance provides a strong foundation for learning AC circuits, RL circuits, transformers, and advanced analog electronics.

May 8, 2026

Most Asked Interview Questions Series for Electronics and VLSI Engineers

📚 Interview Questions Series

Why This Series?

Conclusion

Most Asked Electronics Engineering Interview Questions

1. What is Electronics Engineering?

2. What is the difference between Electrical and Electronics Engineering?

3. What is a Semiconductor?

4. What is the difference between Analog and Digital Electronics?

5. What is a Diode?

6. What is a Transistor?

7. What is an OPAMP?

8. What is a Logic Gate?

9. What is a Flip-Flop?

10. What is a Microprocessor?

11. What is a Microcontroller?

12. What is VLSI?

13. What is FPGA?

14. What is Communication System?

15. What is Embedded System?

Conclusion

Most Asked Analog Electronics Interview Questions

1. What is Analog Electronics?

2. What is the difference between Analog and Digital Signals?

3. What is an Amplifier?

4. What is gain in an amplifier?

5. What is a transistor?

6. What is the difference between BJT and MOSFET?

7. What is an Operational Amplifier (OPAMP)?

8. What is virtual ground in an OPAMP?

9. What is bandwidth?

10. What is feedback in amplifiers?

11. What is an oscillator?

12. What is a filter?

13. What is slew rate in an OPAMP?

14. What is impedance?

15. What are the applications of Analog Electronics?

Conclusion

February 3, 2026

⚡ Resonance

🔌 What Is Impedance?

🎯 Resonance Condition

🔍 What Happens at Resonance?

🧪 LTspice Simulation of Resonance

🔧 Circuit Explanation

🧮 Resonant Frequency Calculation

Step 1: Multiply L and C

Step 2: Square root of LC

Step 3: Multiply by 2π2\pi

Step 4: Take reciprocal

📈 Verification from Simulation

🔚 Conclusion

⚡ Impedance — The Total Opposition

📐 Definition of Impedance (Phasor Form)

❗ Important Clarification

🧮 Magnitude of Impedance

⚙️ Impedance of R, L, and C

🎛️ Frequency Dependence

🔚 Conclusion

⚡ What is Reactance?

🔧 Why is Reactance Needed?

⚖️ Reactance vs. Resistance

🌀 Inductive Reactance — Opposition from a Coil

🔵 Capacitive Reactance — Opposition from a Capacitor

🔄 The Two Types of Reactance

🔚 Conclusion

⚙️ What is an Inductor?

🧱 Structure — How It’s Made

⚙️ How Does an Inductor Work?

Before any current flows:

When a voltage source is connected:

💡 In Simple Words

🔋 Energy Storage in an Inductor

🧮 What is Inductance?

⚡ Voltage–Current Relationship

🧠 Factors Affecting Inductance

🧩 Summary Table

🔚 Conclusion

Step 3: Multiply by $2\pi$