1 Circuit-Analisis - CH 1
1 Circuit-Analisis - CH 1
1 Circuit-Analisis - CH 1
College of Engineering
Department of Communication and Computer
Engineering
2017- 2018
Syllabus
• Introduction – unit of measurement – system of units.
• LAB – introduction to basic components and instruments for electric lab.
• Power of ten – scientific and engineering prefixes – mathematical
operations.
• Current , voltages, and resistors.
• LAB - Bread boarding Circuits.
• Colour coding for resistors- Ohm’s Law- plotting Ohm`s Law.
• Power – energy – efficiency.
• LAB – resistors colour coding.
• Series DC circuits- voltage sources in serial – KVL- voltage divider rule.
• Examples on series circuits.
• LAB- Basic DC circuits – series circuits
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•
Syllabus
Parallel DC circuits- Kirchhoff`s current law-current divider rule.
• Voltage sources in parallel – open and short circuits.
• LAB- Basic DC circuits – parallel circuits.
• Examples on parallel circuits.
• Serial Parallel circuits.
• LAB- Basic DC circuits – serial parallel circuits1.
• Serial parallel circuits – descriptive examples.
• Ladder networks- grounding.
• LAB- Basic DC circuits – serial parallel circuits2.
• Current and voltage sources- conversion between current and voltage
sources.
• LAB – review for previous experiments.
• Branch current method- Mesh analysis (general and format approach).
• Nodal analysis general approach.
• LAB- brunch current methods.
• Nodal analysis format approach.
• Mid Terms Examination 3
•
Syllabus
Bridge networks.
• LAB – Mesh analysis.
• Y to D and D to Y conversion + worked examples.
• Super position theorem.
• LAB – Nodal Analysis.
• Super position theorem – worked examples.
• Thevenin`s theorem.
• LAB – super position theorem.
• Norton`s Theorem.
• Mid course Exam.
• LAB -Thevenin`s and Norton`s theorem.
• Maximum power transfer theorem.
• Magnetic circuits – magnetic fields.
• Course Laboratory Exam.
• Ohm`s law for magnetic circuits- Hysteresis – flux.
• Revision.
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References
1. Introductory circuit analysis – by R. Boylestad –
11th edition
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CHAPTER ONE
Introduction to Powers of 10
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I-2: Engineering Notatio2: Engineering Notation
and Metrriic Prreffiixes
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Example
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Example
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Introduction to Voltage current and
resistor
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. ATOMS AND THEIR STRUCTURE
• Hydrogen: The hydrogen atom (the simplest) made up of two basic
particles, the proton (p) and the electron (e) -1.6*10 -19, as shown in
Figure 1.1. The nucleus of the hydrogen atom is the proton, a positive
charge particle. The orbiting electron carries a negative charge equal
in magnitude to the positive charge of the proton +1.6*10 -19.
•
• In all other elements, the nucleus also contains neutrons, which are
slightly heavier than protons and have no electrical charge. Ex: Helium
atom has two neutrons in addition to two electrons and two protons
• Fig.1.1
• The hydrogen and helium atoms
•
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Atoms and Their Structure
• Nucleus
– Protons
– Electrons
– Neutrons
Fig.1.1
The hydrogen and helium atoms 22
COPPER:
Copper is the most commonly used metal in the
electrical/electronics industry. It has 29 electrons in orbits
around the nucleus, with the 29th electron appearing all by
itself in the 4th shell
Fig.1.2
The copper atom
+ - + +
Unlike charges Like charges repel
attract 23
Energy
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Voltage
• A potential difference of 1 volt (V) exists
between two points if 1 joule (J) of energy is
exchanged in moving 1 coulomb (C) of charge
between the two points
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Voltage
• Notations for sources of voltage and loss of
potential
– E - Voltage sources (volts)
– V - Voltage drops (volts)
• Potential – The voltage at a point with respect
to another point in the electrical system.
Typically the reference point is the ground,
which is at zero potential.
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Voltage
• Potential difference: The algebraic difference in potential (or
voltage) between two points of a network.
• Voltage: When isolated, like potential, the voltage at a point with
respect to some reference such as ground.
• Voltage difference: The algebraic difference in voltage (or
potential) between two points of a system. A voltage drop or rise
is as the terminology would suggest.
• Electromotive force (emf): The force that establishes the flow of
charge (or current) in a system due to the application of a
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difference in potential.
• Ex: find the voltage between two points if 60 J of
energy are required to move a charge of 20 C
betweenV
the
W two
60 J points.
3V
• Soln: Q 20C
Q
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Electric Current
The electric current is the amount of charge per unit time that
passes through a surface that is perpendicular to the motion of
the charges.
Q
I .
t
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EXAMPLE
• Determine the time required for 4*10 electrons
to pass through the imaginary surface o. if the
current is 5 mA.
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Voltage Sources
Dc Voltage sources
– Batteries (chemical action)
– Generators (electromechanical)
– Power supplies (rectification)
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Conductors and Insulators
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Conductors and Insulators
• Insulators are those materials that have very few free electrons
and require a large applied potential (voltage) to establish a
measurable current level
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Ammeters and Voltmeters
• Ammeter (Milliammeter or Microammeter)
– Used to measure current levels
– Must be placed in the network such that the
charge will flow through the meter
• Voltmeter
– Used to measure the potential difference between
two points
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Resistance
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Resistance, R
Resistance takes into account the physical
dimensions of the material
L
R
where: A
L is the length along which
the carriers are moving
A is the cross sectional area
that the free charges move
through.
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Resistance is the amount that a substance or
load is opposing the flow of electrons FOUR FACTORS AFFECTING THE RESISTANCE OF A WIRE
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Color Coding and Standard Resistor Values
G = 1/R (siemens, S)
• A resistance of 1 M is equivalent to a
conductance of 10-6 S and a resistance of 10 is
equivalent to a conductance of 10-1 S.
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Ohmmeters
• An Ohmmeter is used to Measure the
resistance of individual or combined elements
• Resistance is measured by simply connecting
the two leads of the meter across the resistor.
It doesn’t matter which lead goes on which
end.
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Ohm’s Law
Georg Simon Ohm (1787-1854), a German physicist, discovered
Ohm’s law in 1826.
This is an experimental law, valid for both alternating current
(ac) and direct current (dc) circuits.
When you pass an electric current (I) through a resistance (R)
there will be a potential difference or voltage (V) created across
the resistance.
Ohm’s law gives a relationship between the voltage (V), current
(I), and resistance (R) as follows:
V=IR 48
Units & Symbols
Voltage V volt V
Resistance R ohm Ω
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Plotting Ohm’s Law
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Plotting Ohm’s Law
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Example 1
Determine the current resulting from the application of
a 9-V battery across a network with a resistance of 2.2 .
Example 2
Calculate the resistance of a 60-W bulb if a current of
500 mA results from an applied voltage of 120 V.
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Electric Power, P Energy
P .
time
Since the electrical energy is charge times voltage (QV), the
above equation becomes,
QV
P .
t
Since the current is charge flow per unit time (Q/t), the above
equation becomes,
QV Q
P V I V .
t t
Since V = IR, the above equation can also be written as,
2
V
P IV I 2 R .
R
SI Unit of Power: watt(W) 53
Energy
Energy (W) lost or gained by any system is
determined by:
W = Pt
Since power is measured in watts (or joules
per second) and time in seconds, the unit of
energy is the watt second (Ws) or joule (J)
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Killo-watt-hour (kWh)
The SI unit of power is watt, after James Watt (1736-1819),
who developed steam engines.
joule J
watt W .
sec ond s
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Energy
The watt-second is too small a quantity for most
practical purposes, so the watt-hour (Wh) and kilowatt-
hour (kWh) are defined as follows:
Energy (Wh) power (W) time (h)
power (W) time (h)
Energy (kWh)
1000