Kirchhoff’s Voltage Law (KVL) - 3.3 | 3. Revisit to pre-requisite topics | Analog Electronic Circuits - Vol 1
K12 Students

Academics

AI-Powered learning for Grades 8–12, aligned with major Indian and international curricula.

Academics
Professionals

Professional Courses

Industry-relevant training in Business, Technology, and Design to help professionals and graduates upskill for real-world careers.

Professional Courses
Games

Interactive Games

Fun, engaging games to boost memory, math fluency, typing speed, and English skills—perfect for learners of all ages.

games

Interactive Audio Lesson

Listen to a student-teacher conversation explaining the topic in a relatable way.

Introduction to KVL

Unlock Audio Lesson

Signup and Enroll to the course for listening the Audio Lesson

0:00
Teacher
Teacher

Welcome everyone! Today we will dive into Kirchhoff’s Voltage Law, or KVL. Can anyone tell me what KVL states?

Student 1
Student 1

Isn't it about the total voltages in a closed loop summing to zero?

Teacher
Teacher

Exactly! KVL dictates that the sum of all potential differences around any closed loop in an electrical circuit is zero. Think of it this way: every voltage supplied must be 'used up' by the components in the loop.

Student 2
Student 2

So, if I have a battery providing 10 volts in a loop with two resistors, do both need to drop that total?

Teacher
Teacher

Right, Student_2! If one resistor drops 6 volts, the other must drop 4 volts for the total to sum to zero. KVL helps us find unknown voltages. Here's a mnemonic: 'Voltage Finds Balance'—VFB—to remember that voltage in any loop balances out to zero.

Student 3
Student 3

What about AC circuits? Does KVL still apply there?

Teacher
Teacher

Great question! Yes, KVL also applies to AC circuits where voltage and current change over time. Let’s consider time-dependent waveforms in our next session.

Teacher
Teacher

To summarize, KVL ensures that in any closed loop, all voltages must sum to zero, whether in DC or AC circuits.

KVL and AC Signals

Unlock Audio Lesson

Signup and Enroll to the course for listening the Audio Lesson

0:00
Teacher
Teacher

Now that we understand KVL, let’s explore its application in AC circuits. Can anyone explain what happens to voltages in AC signals?

Student 4
Student 4

In AC circuits, the voltages fluctuate or alternate over time, right?

Teacher
Teacher

Exactly, Student_4! AC voltage can be expressed as a sinusoidal function. In such cases, KVL states that the sum of instantaneous voltages at any time must also equal zero. Let's look at this formula: V = V1 sin(ωt) + V2 sin(ωt) + ... and so on. How does this compare to DC analysis?

Student 1
Student 1

In DC, voltage remains constant, while in AC it varies.

Teacher
Teacher

Precisely! And remember, KVL can still be applied regardless of whether the circuit has different frequencies, as long as we assess online components—the total must always balance out. Now, a quick pop quiz—Can we apply KVL in the Laplace domain too?

Student 2
Student 2

Yes, technically we can transform the time-domain signals and sum them in Laplace domain!

Teacher
Teacher

Exactly! Let's summarize: KVL holds true for both AC and Laplace domain signals, ensuring we can analyze complex signals effectively.

Application of KVL in Circuit Analysis

Unlock Audio Lesson

Signup and Enroll to the course for listening the Audio Lesson

0:00
Teacher
Teacher

Now, let’s delve into some practical applications of KVL in circuit analysis. Can anyone suggest how we might use KVL to determine an unknown voltage in a circuit?

Student 3
Student 3

By summing known voltages and solving for the unknown?

Teacher
Teacher

Correct! Here’s a simple example: if you know three voltage drops in a 12V circuit are 5V, 2V, and 3V, what’s the unknown voltage?

Student 4
Student 4

It would be 12V - (5V + 2V + 3V) = 2V.

Teacher
Teacher

Fantastic! Your answer is spot on. That's how KVL plays a vital role in circuit analysis, allowing us to deduce unknown values systematically. Any questions about how KVL supports analyzing complex or non-linear circuits?

Student 1
Student 1

How does it help with non-linear components?

Teacher
Teacher

Wonderful point! KVL applies equally to non-linear circuits—we often linearize non-linear components around the DC operating point to apply KVL effectively. In summary: KVL is crucial for understanding both linear and non-linear circuits.

Introduction & Overview

Read a summary of the section's main ideas. Choose from Basic, Medium, or Detailed.

Quick Overview

This section introduces Kirchhoff’s Voltage Law (KVL) and its application in analog circuits, emphasizing the significance of voltage drops across circuit components.

Standard

Kirchhoff’s Voltage Law (KVL) states that the sum of the electrical potential differences (voltage) around any closed network is zero. This is applied in various contexts including AC circuits and Laplace domain analysis, facilitating circuit analysis in both linear and non-linear scenarios.

Detailed

Kirchhoff’s Voltage Law (KVL)

Kirchhoff’s Voltage Law (KVL) is a fundamental principle in electrical circuit theory that asserts the sum of the potential differences (voltage) around any closed loop in a circuit is equal to zero. In simpler terms, KVL indicates that the total voltage supplied in a loop is equal to the sum of the voltage drops across the components within that loop. This section revisits KVL, stressing its application not only in direct current (DC) circuits but also in alternating current (AC) and in the Laplace domain.

The discussion involves examples with multiple circuit elements connected in a loop, where students learn to calculate potential drops and apply KVL to solve for unknown voltages. The principle is applicable to both linear and non-linear circuits, extending its utility in analyzing complex electronic circuits encountered in analog electronics. KVL becomes essential when students progress to more sophisticated circuits, including those involving transient responses and time-dependent behaviors in signals.

Youtube Videos

Analog Electronic Circuits _ by Prof. Shanthi Pavan
Analog Electronic Circuits _ by Prof. Shanthi Pavan

Audio Book

Dive deep into the subject with an immersive audiobook experience.

Introduction to Kirchhoff’s Voltage Law (KVL)

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

So, similarly for KVL; so, for KVL also we can deploy this KVL for AC signal in that case of course, the signal it will be voltage and also the signal may be even in Laplace domain. So, there also we can use KVL. So, quickly just to complete that in a KVL what you do suppose you do have a circuit where you do have multiple elements are connected together and then if they are forming a closed loop.

Detailed Explanation

Kirchhoff’s Voltage Law (KVL) states that the sum of the potential differences (voltages) around any closed loop in a circuit must equal zero. This means that if you traverse around a loop in a circuit, the total of the voltages (gains and drops) should cancel out. This principle holds true for both AC and DC circuits and can even be applied in the Laplace domain for systems analyzed in the frequency domain.

Examples & Analogies

Imagine walking around a circular track. If you start at one point and make it all the way around without stopping or leaving the track, you must end up back at the point where you started—this is similar to how voltages must 'come back to zero' around a loop in a circuit.

Understanding Voltage Drops in a Loop

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

Say let you consider we do have 3 elements or maybe 4 elements in a circuit and then we do have different nodes here different circuit nodes are there. And then if I say that from here to here the potential difference is node 1 to 2 or we can say simply you can say that this is V drop here it is V from negative to positive.

Detailed Explanation

In practice, when applying KVL, you look at each component connected in a loop and note the voltage drops or rises across them. For example, if you have several resistors in series, you would add the voltage drops across each resistor to determine the overall voltage around the loop. If you find that the total voltage adds up to zero, then KVL is satisfied.

Examples & Analogies

Think of buying items at a store—each item has a price (voltage). If you add up all the prices and compare it to the amount of money you have (total voltage from the power source), your money must match the total cost when you're done shopping, just as the voltage drops must balance the voltage gains in a circuit.

Applying KVL with AC Signals

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

For instance, if we consider V , V may be say V sin (ω t), V maybe it is having its own amplitude and so on. So, likewise you may have all of them maybe having their own signal and again you can add all of them and then you can say that according to the KVL this is equal to 0.

Detailed Explanation

KVL can also be applied in AC circuits. In this context, the voltage across components varies with time and can be expressed as sinusoidal functions. When applying KVL, each voltage signal must still sum to zero. Whether in AC or DC, KVL acts the same way regardless of how many cycles per second the signal happens.

Examples & Analogies

Imagine you are on a ferris wheel that moves up and down. The heights at which you stop (like voltages) vary continuously as you turn. If you measure the total height at different points and find that everything balances out to the initial height when you complete the ride, you've satisfied the principle, similar to how KVL works for voltages in a circuit.

Using Laplace Transform with KVL

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

So, once you are representing each of this individual current from time domain to Laplace domain then you can add up all of these currents in a Laplace domain and then you can add them together and then you say that the summation is equal to 0.

Detailed Explanation

In advanced circuit analysis, it can be beneficial to convert time-domain signals into the Laplace domain. KVL still applies in this context; you can represent voltages using complex numbers in the Laplace domain and perform KVL analyses there. The resulting equations will help identify circuit behaviors like stability and response.

Examples & Analogies

Think of translating a book into another language. The sentences ( voltages) may change form, but their meanings (the overall concept of voltage summing to zero) remain intact. Just like how KVL functions whether you're reading in your native tongue or a translated version, if you apply KVL in the Laplace domain, it will retain its validity.

Definitions & Key Concepts

Learn essential terms and foundational ideas that form the basis of the topic.

Key Concepts

  • KVL states that the total of all voltage drops in a closed loop is zero.

  • KVL applies to both DC and AC circuits.

  • Effective analysis of circuits is achieved using KVL, including non-linear elements by approximation.

Examples & Real-Life Applications

See how the concepts apply in real-world scenarios to understand their practical implications.

Examples

  • In a loop with a 12V supply and three resistors dropping 5V, 2V, and 3V, the unknown voltage can be found using KVL.

  • AC signals can be represented as V = V0 sin(ωt), and KVL asserts their sum in a closed loop is also zero.

Memory Aids

Use mnemonics, acronyms, or visual cues to help remember key information more easily.

🎵 Rhymes Time

  • In loops of circuits where currents flow, KVL says the voltages must balance, you know!

📖 Fascinating Stories

  • Imagine a battery in a loop, its voltages dance, with resistors playing their part, until the last one takes a chance, making sure the sum is always zero – that’s KVL’s advance!

🧠 Other Memory Gems

  • Remember 'VFB' - Voltage Finds Balance - to easily recall KVL.

🎯 Super Acronyms

KVL

  • 'Kirchhoff’s Voltage Law' - includes both voltage and loop; remember it equates to zero
  • or you’ll end up in a loop!

Flash Cards

Review key concepts with flashcards.

Glossary of Terms

Review the Definitions for terms.

  • Term: Kirchhoff’s Voltage Law (KVL)

    Definition:

    A principle stating that the total sum of electrical potential differences around a closed loop in a circuit equals zero.

  • Term: AC Circuit

    Definition:

    An electric circuit powered by alternating current, where the flow of electric charge periodically reverses direction.

  • Term: Laplace Domain

    Definition:

    A transformed domain used for analyzing linear time-invariant systems, allowing for easier calculations with time-dependent signals.

  • Term: Nonlinear Circuit

    Definition:

    A circuit whose current-voltage relationship is not a straight line, leading to circuit behavior that is not directly proportional.