kirchhoff's voltage law experiment

• Network Sites:
• Technical Articles
• Market Insights

• Or sign in with
• iHeartRadio

• Kirchhoff’s Voltage Law (KVL)

Join our Engineering Community! Sign-in with:

• Direct Current (DC)

Divider Circuits And Kirchhoff's Laws

• Voltage Divider Circuits
• Current Divider Circuits and the Current Divider Formula
• Kirchhoff’s Current Law (KCL)

What is Kirchhoff’s Voltage Law (KVL)?

The principle known as Kirchhoff’s Voltage Law (discovered in 1847 by Gustav R. Kirchhoff, a German physicist) can be stated as such:

“The algebraic sum of all voltages in a loop must equal zero”

By algebraic , I mean accounting for signs (polarities) as well as magnitudes. By loop , I mean any path traced from one point in a circuit around to other points in that circuit, and finally back to the initial point.

Demonstrating Kirchhoff’s Voltage Law in a Series Circuit

Let’s take another look at our example series circuit, this time numbering the points in the circuit for voltage reference:

If we were to connect a voltmeter between points 2 and 1, red test lead to point 2 and the black test lead to point 1, the meter would register +45 volts. Typically the “+” sign is not shown but rather implied, for positive readings in digital meter displays. However, for this lesson, the polarity of the voltage reading is very important and so I will show positive numbers explicitly:

When a voltage is specified with a double subscript (the characters “2-1” in the notation “E 2-1 ”), it means the voltage at the first point (2) as measured in reference to the second point (1). A voltage specified as “E cd ” would mean the voltage as indicated by a digital meter with the red test lead on point “c” and the black test lead on point “d”: the voltage at “c” in reference to “d”.

If we were to take that same voltmeter and measure the voltage drop across each resistor , stepping around the circuit in a clockwise direction with the red test lead of our meter on the point ahead and the black test lead on the point behind, we would obtain the following readings:

We should already be familiar with the general principle for series circuits stating that individual voltage drops add up to the total applied voltage, but measuring voltage drops in this manner and paying attention to the polarity (mathematical sign) of the readings reveals another facet of this principle: that the voltages measured as such all add up to zero:

In the above example, the loop was formed by the following points in this order: 1-2-3-4-1. It doesn’t matter which point we start at or which direction we proceed in tracing the loop; the voltage sum will still equal zero. To demonstrate, we can tally up the voltages in loop 3-2-1-4-3 of the same circuit:

This may make more sense if we re-draw our example series circuit so that all components are represented in a straight line:

It’s still the same series circuit, just with the components arranged in a different form. Notice the polarities of the resistor voltage drops with respect to the battery: the battery’s voltage is negative on the left and positive on the right, whereas all the resistor voltage drops are oriented the other way: positive on the left and negative on the right. This is because the resistors are resisting the flow of electric charge being pushed by the battery. In other words, the “push” exerted by the resistors against the flow of electric charge must be in a direction opposite the source of electromotive force.

Here we see what a digital voltmeter would indicate across each component in this circuit, black lead on the left and red lead on the right, as laid out in horizontal fashion:

If we were to take that same voltmeter and read voltage across combinations of components, starting with the only R 1 on the left and progressing across the whole string of components, we will see how the voltages add algebraically (to zero):

The fact that series voltages add up should be no mystery, but we notice that the polarity of these voltages makes a lot of difference in how the figures add. While reading voltage across R 1 —R 2 , and R 1 —R 2 —R 3 (I’m using a “double-dash” symbol “—” to represent the series connection between resistors R 1 , R 2 , and R 3 ), we see how the voltages measure successively larger (albeit negative) magnitudes, because the polarities of the individual voltage drops are in the same orientation (positive left, negative right).

The sum of the voltage drops across R 1 , R 2 , and R 3 equals 45 volts, which is the same as the battery’s output, except that the battery’s polarity is opposite that of the resistor voltage drops (negative left, positive right), so we end up with 0 volts measured across the whole string of components.

That we should end up with exactly 0 volts across the whole string should be no mystery, either. Looking at the circuit, we can see that the far left of the string (left side of R 1 : point number 2) is directly connected to the far right of the string (right side of battery: point number 2), as necessary to complete the circuit.

Since these two points are directly connected, they are electrically common to each other. And, as such, the voltage between those two electrically common points must be zero.

Demonstrating Kirchhoff’s Voltage Law in a Parallel Circuit

Kirchhoff’s Voltage Law (sometimes denoted as KVL for short) will work for any circuit configuration at all, not just simple series. Note how it works for this parallel circuit:

Being a parallel circuit, the voltage across every resistor is the same as the supply voltage: 6 volts. Tallying up voltages around loop 2-3-4-5-6-7-2, we get:

Note how I label the final (sum) voltage as E 2-2 . Since we began our loop-stepping sequence at point 2 and ended at point 2, the algebraic sum of those voltages will be the same as the voltage measured between the same point (E 2-2 ), which of course must be zero.

The Validity of Kirchhoff’s Voltage Law, Regardless of Circuit Topology

The fact that this circuit is parallel instead of series has nothing to do with the validity of Kirchhoff’s Voltage Law. For that matter, the circuit could be a “black box”—its component configuration completely hidden from our view, with only a set of exposed terminals for us to measure the voltage between—and KVL would still hold true:

Try any order of steps from any terminal in the above diagram, stepping around back to the original terminal, and you’ll find that the algebraic sum of the voltages always equals zero.

Furthermore, the “loop” we trace for KVL doesn’t even have to be a real current path in the closed-circuit sense of the word. All we have to do to comply with KVL is to begin and end at the same point in the circuit, tallying voltage drops and polarities as we go between the next and the last point. Consider this absurd example, tracing “loop” 2-3-6-3-2 in the same parallel resistor circuit:

Using Kirchhoff’s Voltage Law in a Complex Circuit

KVL can be used to determine an unknown voltage in a complex circuit, where all other voltages around a particular “loop” are known. Take the following complex circuit (actually two series circuits joined by a single wire at the bottom) as an example:

To make the problem simpler, I’ve omitted resistance values and simply given voltage drops across each resistor. The two series circuits share a common wire between them (wire 7-8-9-10), making voltage measurements between the two circuits possible. If we wanted to determine the voltage between points 4 and 3, we could set up a KVL equation with the voltage between those points as the unknown:

Stepping around the loop 3-4-9-8-3, we write the voltage drop figures as a digital voltmeter would register them, measuring with the red test lead on the point ahead and black test lead on the point behind as we progress around the loop. Therefore, the voltage from point 9 to point 4 is a positive (+) 12 volts because the “red lead” is on point 9 and the “black lead” is on point 4.

The voltage from point 3 to point 8 is a positive (+) 20 volts because the “red lead” is on point 3 and the “black lead” is on point 8. The voltage from point 8 to point 9 is zero, of course, because those two points are electrically common.

Our final answer for the voltage from point 4 to point 3 is a negative (-) 32 volts, telling us that point 3 is actually positive with respect to point 4, precisely what a digital voltmeter would indicate with the red lead on point 4 and the black lead on point 3:

In other words, the initial placement of our “meter leads” in this KVL problem was “backward.” Had we generated our KVL equation starting with E 3-4 instead of E 4-3 , stepping around the same loop with the opposite meter lead orientation, the final answer would have been E 3-4 = +32 volts:

It is important to realize that neither approach is “wrong.” In both cases, we arrive at the correct assessment of voltage between the two points, 3 and 4: point 3 is positive with respect to point 4, and the voltage between them is 32 volts.

• Kirchhoff’s Voltage Law (KVL): “The algebraic sum of all voltages in a loop must equal zero”

RELATED WORKSHEETS:

• Kirchhoff’s Laws Worksheet
• Textbook Index

Lessons in Electric Circuits

Volumes », chapters ».

• 1 Basic Concepts Of Electricity
• 2 Ohm's Law
• 3 Electrical Safety
• 4 Scientific Notation And Metric Prefixes
• 5 Series And Parallel Circuits

Pages »

• 7 Series-parallel Combination Circuits
• 8 DC Metering Circuits
• 9 Electrical Instrumentation Signals
• 10 DC Network Analysis
• 11 Batteries And Power Systems
• 12 Physics Of Conductors And Insulators
• 13 Capacitors
• 14 Magnetism and Electromagnetism
• 15 Inductors
• 16 RC and L/R Time Constants
• 17 Contributor List
• Alternating Current (AC)
• Semiconductors
• Digital Circuits
• EE Reference
• DIY Electronics Projects
• Advanced Textbooks Practical Guide to Radio-Frequency Analysis and Design
• Designing Analog Chips

Related Content

• Kirchhoff’s Laws
• Peak Voltage Calculator
• Ohm’s Law, Kirchhoff’s Laws, and Power Equations
• RMS Voltage Calculator
• Ohm’s Law Calculator
• Understanding Kirchhoff’s Voltage Law (KVL): Principles and Applications

I believe the multimeter readouts in images 5 and 6 (from the top of the article) are incorrect. Specifically, the third and forth multimeter readouts from the left should read -15v and + 45v, respectively.

• D dalewilson June 28, 2021 Good catch! The multimeter displays in the 3 lower rows of this figure are also incorrect, but the bold notes next to them display the correct voltages. We will work to get this corrected. Thank you for letting us know. Like. Reply

In the “Demonstrating Kirchhoff’s Voltage Law in a Parallel Circuit” section, why is E 3-6 not a consideration? I must have missed something, so could somebody please point me back to the resource that explains? Many thanks.

• V varga November 13, 2022 I also do not understand that part. Any answers? Like. Reply

Thanks for sharing knowledge with us

You May Also Like

Würth Elektronik Introduces PFC Inductor Family

In Partnership with Würth Elektronik eiSos GmbH & Co. KG

Memristor Prototype May Give AI Chips a Sense of Time

by Aaron Carman

New MediaTek SoC Speeds Up Generative AI Processing at the Edge

by Jake Hertz

Smart Sensors - Enabling the Intelligent IoT

Extremely High Throughput with Wi-Fi 7

by Rohde & Schwarz

Welcome Back

Don't have an AAC account? Create one now .

Forgot your password? Click here .

• About Contact Sing up Log in
• Business & Industries
• Shipping & Logistics
• Markets & Trading
• Finance & Loan
• Automobiles
• Cryptocurrency
• Beauty & Skin Care
• Gift & Jewellery
• Pets & Animals
• Software & Web Development
• Digital Marketing
• Latest Technologies
• Education & Training
• Jobs & Career
• Health & Fitness
• Medical & Health
• Sports & Athletics

To verify the Kirchhoff's voltage law and Kirchhoff's current law for the given circuit

Aim: verification of kirchoff's laws, apparatus required.

Circuit Diagrams

Given circuit.

1. KVL Circuit

Practical Circuit for KVL

2. KCL Circuit

Practical Circuit for KCL

Theory for Kirchhoff's Current and Kirchhoff's Volatage Law

a) Kirchhoff's Voltage law states that the algebraic sum of the voltage around any closed path in a given circuit is always zero. In any circuit, voltage drops across the resistors always have polarities opposite to the source polarity. When the current passes through the resistor, there is a loss in energy and therefore a voltage drop. In any element, the current flows from a higher potential to lower potential. Consider the fig shown above in which there are 3 resistors are in series. According to kickoff's voltage law.

V = V1 + V2 + V3

b) Kirchhoff's current law states that the sum of the currents entering a node equal to the sum of the currents leaving the same node. Consider the fig shown above in which there are 3 parallel paths. According to Kirchhoff's current law.

I = I1 + I2 + I3

Procedure for Kirchhoff's Voltage law:

1. Connect the circuit as shown in fig (2a).

2. Measure the voltages across the resistors.

3. Observe that the algebraic sum of voltages in a closed loop is zero.

Procedure for Kirchhoff's current law:

1. Connect the circuit as shown in fig (2b).

2. Measure the currents through the resistors.

3. Observe that the algebraic sum of the currents at a node is zero.

Observation Table for KVL

Observation Table for KCL

Precautions

• Avoid loose connections.
• Keep all the knobs in minimum position while switch on and off of the supply.

Viva Questions

• What is another name for KCL & KVL?
• Define network and circuit?
• What is the property of inductor and capacitor?

Latest Post

Best Slots for Playing in Casinos by top10gambling.net

Best Crypto Casino Bonuses & Promotions by top10gambling.net

When Choose Best Payout Casinos By Suomionlinekasinot.com

All About Android Casinos By Toppnorskekasinoer.com

Elevate Your Practice: Essential Features to Seek in Chiropractic Tables for Clinics

Enhancing Business Performance with iCFO.pro

Megaway video slot - Reviews of the Best Megaway

Related categories.

• Instrumentation & Measurement
• Analog & Digital Communication
• Analog Electronics
• Digital Electronics
• Electronic Devices & Circuits
• Digital Circuit System
• Digital Communication
• Electronic Circuit Design
• Microprocessor & Interfacing
• Electrical Machines 1
• Electrical Machines 2
• Power Electronics

Electrical Lab Experiment list

• 1 To conduct Open circuit vs Short circuit tests on single phase transformer
• 2 To measure the displacement vs to determine the characteristics of LVDT (Linear Variable Differential Transformer).
• 3 To plot the transistor (BJT) characteristics of CE configuration.
• 4 To find the forward vs reverse bias characteristics of a given Zener diode.
• 5 To perform Swinburne's test on the given DC machine
• 6 To verify the Kirchhoff's voltage law vs Kirchhoff's current law for the given circuit
• 7 To measure the strain using strain gauge.

Laboratory Experiment Categories

• Electrical and Electronics
• Civil Engineering
• Engineering Mechanics
• Mechanical Engineering
• Biomedical Engineering

Get all latest content delivered to your email a few times a month.

Verification of Kirchhoffs Laws

Table of Contents

Verification of Kirchhoff’s laws

Breadboard, Batteries or DC regulated power supply, Resistors, Multimeter, Connecting wires, Alligator clips, PC with Multisim software for simulation.

Kirchhoff’s Current Law

This law is also called Kirchhoff’s point rule, Kirchhoff’s junction law (or nodal law), and Kirchhoff’s first law.

Statement: The algebraic sum of all the currents at any node or a junction of a circuit is zero.

This law is particularly useful when applied at a position where the current is split into pieces by several wires. The node is a point in the network where two or more circuit elements meet.

The direction of incoming currents to a node is taken as positive while the outgoing currents is taken as negative.

n is the total number of branches with currents flowing towards or away from the node.

However, by Kirchhoff’s current law, I 3 = I 1 + I 2 , and thus, as shown in Figure, we need to use only two current designations. In other words, if we know any two of the three currents, we can then find the third current.

In the same way, if there are, say, four branch currents entering and leaving a node point, and if we know any three of the currents, we can then find the fourth current, and so on.

Kirchhoff’s Voltage Law

Statement: In a closed circuit, the algebraic sum of all the EMFs and the algebraic sum of all the voltage drops (product of current and resistance) is zero.

The rise in potential is taken as positive and the fall in potential is taken as negative.

Consider the following circuit.

Applying Kirchhoff’s Voltage law to the above loop,

Note that V2 appears as a voltage drop, because we go through that battery from

positive to negative. Alternatively, putting all the battery voltages on the righthand side, the above equation becomes

Circuit Diagram

• Assume the current flowing through each resistor as I 1 , I 2 and I 3 .
• Assume the direction of currents flowing through each branch (resistor).
• Measure the current flowing into the top node of the circuit from each of the three branch
• To measure the current, you should break the circuit to insert the
• You must also measure the polarity of the current in a reliable If the current flows into the node, then the current should be measured from the positive terminal to the negative terminal.
• If the magnitude of the current is negative, write it as negative only.
• Record these measured currents.
• Add the three currents to check that the sum of the currents is zero (or close to zero) or sum of the incoming currents is equal to sum of outgoing currents.
• Connect the circuit as per the circuit diagram on bread board.
• Switch on the power supply.
• Measure V R1 , V R2 and V R3 .
• Select any desired loop say loop (1), apply KVL as per given in observation table and verify the result.
• Repeat above step for another loop.

Precautions

• All the connection should be
• Ammeter must be connected in series while voltmeter must be connected in parallel to the components (resistors).
• Before circuit connection working condition of all the components must be checked.
• The electrical current should not flow the circuit for long time, otherwise its temperature will increase and the result will be

Observations

R 1 =_____ Ω

R 2 =_____ Ω

R 3 =_____ Ω

For Kirchhoff’s current Law

Current across individual resistor R 1 , R 2 & R 3

I 1 = ____ A

I 2 = ____ A

I 3 = ____ A

For Kirchhoff’s voltage Law

V 1 = _____ V

V 2 = _____ V

V R1 = _____ V

V R2 = _____ V

V R3 = _____ V

Calculations

Verifying KCL using measured values:

I 1 + I 2 + I 3 = ——–.

Verifying KVL using measured values:

[Apply KVL to loop 1 and loop 2 and verify]

The sum of current going toward the junction is _____A .

The sum of current going away from the junction is _____A.

Similarly, sum of e.m.f. and potential drops in first loop is _____V.

and sum of e.m.f. and potential drops in second loop is _____V.

At a node, sum of incoming current is equal to sum of outgoing current hence Kirchhoff’s current law is verified.

In a closed circuit, the algebraic sum of all the EMFs and the algebraic sum of all the voltage drops (product of current and resistance) is zero, hence Kirchhoff’s voltage law is verified.

Recent posts

Multitasking in RTOS

Architecture of rtos in embedded systems, need, requirement and specifications of rtos, related posts:.

• Verification of Nortons Theorem
• Verification of Superposition Theorem
• Verification of Thevenins theorem
• Verification of Maximum Power Transfer Theorem
• Verify Z-Parameters of Two-port Network
• Verify Y-Parameters of Two-port Network
• Verify Hybrid Parameters of Two-port Network
• Study the transient response of a series RC circuit
• Study the transient response of a series RL circuit

1 thought on “Verification of Kirchhoffs Laws”

Hello electronicsforyou.in admin, Thanks for the in-depth post!

Comments are closed.

• Sign in / Register
• Administration
• Edit profile

Study and Verify Kirchhoff's Laws (KCL & KVL)

• kirchhoff's Laws.docx - 3288 kB

--> --> -->