DIPLOMA-PHYSICS

INTRODUCTION

Kirchhoff’s second law, generally known as the law of conservation of energy, says that « in an electrical circuit, the algebraic sum of all potential differences along a closed loop is zero. »This rule is important in the construction of electrical circuits.Engineers may verify that the voltage needs of various components are satisfied by applying this law in crucial circuits. This rule is often applied in mesh analysis, a technique for solving circuits with numerous loops.Engineers may use this rule to better understand voltage distribution, assess complicated circuits, measure voltage, and verify correct circuit performance.

KIRCHHOFF’S SECOND LAW (KVL)

Kirchhoff’s subsequent(second) law is otherwise called Voltage law (OR) Loop law.This law depends on LAW OF CONSERVATION OF ENERGY.Kirchhoff’s subsequent law expresses that  » THE ALGEBRAIC SUM OF ALL THE POTENTIAL DIFFERENCES ALONG A CLOSED LOOP IS ZERO ».

CONVENTIONS

• Accept any course (direction) as the heading of traversal (direction of traversal). (Either clockwise or anticlockwise).
• EMF of the cell is POSITIVE in the event that the bearing of the crossing (direction of the traversal) is from its NEGATIVE terminal to POSITIVE terminal. (NPP)
• EMF of the cell is NEGATIVE assuming the heading of the crossing (direction of the traversal) is from its POSITIVE terminal to NEGATIVE terminal of the battery. (PNN)
• The IR item is taken as POSITIVE on the off chance that the resistor is crossed a similar way as the expected to be current. (If the resistor is traversed in the same direction as the assumed current.)

EXAMPLE

SOLUTION

SOLUTION

KIRCHHOFF’S FIRST LAW (KCL)

INTRODUCTION

Kirchhoff’s first law, generally known as the conservation of charge, asserts that « the algebraic sum of current at any junction in an electrical circuit is zero. »We may find any inconsistencies or deviations in circuit values by applying this formula at various junctions in a circuit.This rule is important to modern measuring techniques and is frequently applied in electrical engineering.This rule determines how current is dispersed in a circuit, is vital in electrical circuit design, and is critical in recognizing defects or irregularities in electrical systems.This equation is a handy tool for solving a wide range of electrical circuit difficulties.In this topic, let us look into this law.

KIRCHHOFF’S FIRST LAW

This law is based on LAW OF CONSERVATION OF CHARGES.This law is widely used in electrical engineering.The current law relies on the fact that the net charge in the wires and components is constant.The current law is applicable to any lumped network irrespective of the nature of the network.

KIRCHHOFF’S FIRST LAW – STATEMENT

Kirchhoff’s first law states that « IN AN ELECTRIC CIRCUIT, THE ALGEBRAIC SUM OF CURRENT AT ANY JUNCTION IS ZERO ».

TOTAL CURRENT ENTERING A JUNCTION EQUALS TOTAL CURRENT LEAVING THE JUNCTION.

Current flowing towards the junction is taken as POSITIVE and current flowing away from the junction is taken as NEGATIVE.

KIRCHHOFF’S FIRST LAW-IMAGE

KIRCHHOFF’S FIRST LAW- EXAMPLE

CONCLUSION

Kirchhoff’s laws, which are based on the concept of charge and energy conservation, allow us to understand and anticipate the behavior of electrical circuits.Kirchhoff’s laws are useful tools for electrical engineers and other professionals who work with circuits.These rules are employed in the solution of complicated circuit issues and the design of electrical systems.

• Kirchhoff’s laws are used to calculate the current through a resistor (use Kirchhoff’s current law to write an equation that sums the current entering and leaving the resistor), 
• voltage across a capacitor (use Kirchhoff’s current law and Kirchhoff’s voltage law to write an equation that sums the voltage drop around the capacitor), and
•  power dissipated by a resistor (use Kirchhoff’s current law and Kirchhoff’s voltage law to write an equation that relates the power voltage and the resistance of the resistor and to determine  the behavior of  a circuit under different conditions.

KIRCHHOFF’S LAW NUMERICAL

Use Kirchhoff’s law write the three equations that may be used  to obtain the values of  three unknown currents I₁, I₂ and I₃ in the branches as shown in the  following circuit.

SOLUTION

CLOSED LOOP ABCA :

CLOSED LOOP ADCA :

CLOSED LOOP BCDEB :

SOLVING THE EQUATIONS:

KIRCHHOFF’S LAW-NUMERICAL (3)

INTRODUCTION

Kirchhoff’s laws, the current law (which applies the concept of charge conservation) and the voltage law (which applies the principle of energy conservation), give a systematic way to addressing complicated circuits.Kirchhoff’s current law is crucial in contemporary measurement techniques and is commonly used in electrical engineering to establish how current is distributed in a circuit, is critical in electrical circuit design, and is critical in detecting flaws or abnormalities in electrical systems.The Kirchhoff’s voltage law is frequently used in mesh analysis, which is a technique for analyzing circuits with many loops.Engineers may use this rule to better understand voltage distribution, evaluate complex circuits, measure voltage, and ensure proper circuit performance.In this discussion, we will look at determining the unknown values, illustrating how they might be used in practice.

NUMERICAL

Find the current in each wire using Kirchhoff’s voltage law (the second law)

SOLUTION

MODIFIED CIRCUIT

The modified circuit is shown above. All elements are connected in series.Here we can select the direction of  traversal as anti-clockwise.

In a series combination of the circuit,the current through all the components is the same.

Consider the current through each element be I . Now we can apply Kirchhoff’s second law

CONCLUSION

Kirchhoff’s laws, based on the notion of charge and energy conservation, enable us to understand and predict the behavior of electrical circuits.Kirchhoff’s laws are useful tools for electrical engineers and other circuit specialists.These guidelines are used to solve complex circuit problems and to construct electrical systems.Kirchhoff’s laws allow us to calculate current, voltage, and resistance in a circuit.Engineers and students can improve their abilities to solve complicated circuits and create efficient electrical systems by exercising these rules.Kirchhoff’s rules remain an important framework in the field of electrical engineering for technological and innovative breakthroughs.