Kirchhoff's rules provide a means of obtaining enough independent equations to solve for currents in an electrical circuit. They were first described in 1845 by German physicist Gustav Kirchhoff and consist of two equalities: (1) the Junction Rule states that the sum of currents entering a junction equals the sum leaving, based on conservation of charge, and (2) the Loop Rule states that the sum of voltages around a closed conducting loop must be zero, based on conservation of energy. Kirchhoff's rules can be applied to traffic flow analysis and are the basis of circuit simulation software used in integrated circuit design.

1. Kirchhoff’s
Rules

2. Objectives
• For us to know what are the kirchhoff’s
rules and how to compute currents
using it.
• To be familiar with the formulas and
different concepts.

3. Features
• Kirchhoff's rules provide a means of obtaining
enough independent equations to solve for the
currents flowing in an electrical circuit.
• Kirchhoff's circuit laws are two equalities that deal
with the current and potential difference in the
lumped element model of electrical circuits.
• They were first described in 1845 by German
physicist Gustav Kirchhoff.

4. Definition of Terms
• Junction- a point where three or more conductors
meet.
• Electromotive force- is the voltage developed by
any source of electrical energy such as a battery or
dynamo.[
• Law of Conservation of Charge- current is flow of
charge per time, and if current is constant, that
which flows into a point in a circuit must equal that
which flows out of it.
• Law of Conservation of Energy- the total energy
gained per unit charge must equal the amount of
energy lost per unit of charge.

5. Kirchhoff’s Rules
• Junction/Voltage Rule-this is based on the
conservation of charge: the sum of currents
entering a junction is equal the sum leaving.
Formula: i2 + i3 = i1 + i4
• Loop/Current Rule-this is based on the conservation
of energy: The sum of voltages around a closed
conducting loop must be zero.
Formula: v1 + v2 + v3 + v4 = 0

6. Sample Problem

7. Junction Rule:
I0=I1+I2
I0= (-0.0375)+(0.015)
I0= -0.0225 A
Solution:
Loop Rule:
A: -I2(100Ω)+1.5=0
-100I2+1.5=0
I2=0.015 A
B: -9v-I1(200Ω)+I2(100Ω)=0
-9-200I1+(0.015)(100)=0
-200I1=7.5
I1= -0.0375 A

8. Applications

9. Objectives
• To know how the rules could be
applied and could contribute to our
everyday lives and to the society.
• For us to understand the Kirchhoff’s
rules in a wider perspective.

10. New Developments
• With China's economic rapid development and expansion of urban
areas, urban traffic congestion is becoming increasingly obvious,
following from that is not optimistic, the coming of the scarcity of
urban road resources and traffic situation. At the present time, the
simulation model on domestic and foreign does not really reflect that
the traffic flow from the emergence and development of the life-cycle
process to reduce traffic flow. Kirchhoff's law for the basic
theory of the analysis, identify the relationship between the
resistances of traffic and the traffic flow, traffic volume, and so on, to
obtained analysis model, and reveal the law of the traffic flow life-cycle.
ADVANTAGES:
• It could really help to reduce traffic by just applying the concept of Kirchhoff’s
rules.
DISADVANTAGES:
• There could still be limitations because flows in electric currents are
spontaneous and the flows in traffics are sometimes unpredictable.

11. Implication to Science and
Technology
• A matrix version of Kirchhoff's current law is the basis of most
circuit simulation software, such as SPICE. It is a powerful
program that is used in integrated circuit and board-level
design to check the integrity of circuit designs and to predict
circuit behavior.
• Kirchhoff's current law combined with Ohm's Law is used in
nodal analysis, a method of determining the voltage
(potential difference) between "nodes.
• Kirchhoff's rules can be used to analyze any circuit and
modified for those with EMFs, resistors, capacitors and more.

12. Single-Loop
Circuits

13. Objective
For us, to learn about
single-loop circuits and
how it help us in our
everyday lives.

14. Definition of Terms
• Electrical Circuit- is a network
consisting of a closed loop, giving a
return path for the current
• Direct current (DC)- is the
unidirectional flow of electric charge

16. Application
Without circuits, electricity could
be impossible, and without
electricity, we will suffer.
Especially these modern days.