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ELECTRIC CIRCUITS 1
ENT161/4
En. Mohd Arinal
Prof. Madya Dr. Mohd Rizon
COURSE STRUKTURE
Final Exam
Assessment
Lab
: 50%
: 10%
: 40%
100%
COURSE OBJEKTIVE
Learn about Electric Circuits component and
AD/DC circuit analysis method
COURSE SYLLABUS
Circuit Elements and Variables
SI Unit, Voltage and Current, Power, Energy, Basic Circuit Elements (
Passive and Active), Voltage and Current Source, Ohm’s law, Kirchoff’s
Law, Circuit Model, Circuit with Dependent Source. Introduction to an
Inductor, Voltage relationship, Current, Power and Energy, Capacitor and
Combination of Serial-Parallel Inductor and Capacitor.
Resistance Circuit
Serial/Series Resistors, Circuit Voltage/Current Dividers, Measurement of
Voltage and Current, Wheatstone Bridge and Equal Circuit Delta-Wye (PiTee)
Circuit Analysis Method
Node-Voltage Method and this Method encompass Dependent Source and
Special Case. Introduction to Mesh-Current Method which encompass
Dependent Source and Special Case. Point Transformation. Equivalent
Circuits of Thevenin and Norton. Maximum Power Transfer and
Superposition.
Mutual Inductance
Introduction to Self Induction, Concepts of Mutual Inductance, Induced
Mutual Polar Voltage, Energy Calculation, Linear and Ideal Transformer,
Coupled Magnet in Equivalent Roll Circuit, Ideal Transformer in Equivalent
Circuit.
RL and RC circuits first-order response
RL and RC circuit original response, step response (forced function) RL and
RC circuits, general solution of original and step responses, sequential
switching, introduction to original and step RLC circuit.
Steady state Sinusoidal analysis
Sine Source, Sine Response, Phase Concept, Circuits Passive Element in
Frequency Domain, Impedance and Reactance, Kirchoff’s Law in
Frequency Domain, Circuit Analysis Techniques in Frequency Domain.
Step Frequency in AC Circuit
Step Frequency (Magnitude Plot and Phase Stripe Pass, Stripe Limit), Cut
Frequency, Typical Filter Type, Low-pass Filter in RL and RC Circuits, HighPass Filter in RL and RC Circuits, RLC Stripe Pass Filter, Frequency
Response using Bode Diagram.
Steady state Sinusoidal Power calculation
Real-Time Power, Average and Reactive Power, Force Calculation and
RMS Value, Complex and Triangulation Power, Maximum Force Transfer in
Impedance Term.
Power Circuits Systems
One and Two Phase Systems, Equal Three Phase Point Voltage, Y-Delta
Circuit Analysis, Power Calculation in Equal Three Phase Circuit, Average
Power Calculation in Three Phase Circuit.
Circuit Elements and Variables
Circuits analysis revision
SI Units
Voltage and Current, Power, Energy
Basic Circuit Elements ( Passive and
Active)
Voltage and Current Source
Ohm’s law
Kirchoff’s Law
Circuit Model
Circuit with Dependent Source
Circuit Elements and
Variables
Introduction to an Inductor
Voltage relationship
Current, Power and Energy
Capacitor and Combination of SerialParallel Inductor and Capacitor
Circuits analysis revision
Analysis : Study (Mathematics) about complex
identity and the mutually parts connection.
Circuits : An arrangement of physical
components that use voltage, current, and
resistance to perform some useful function.
Analisis litar : Based on mathematical
techniques and is used to predict the behavior of
the circuit model and its ideal circuit
components.
SI Units
SI : International System of Unit introduce by
National Bureau of Standards in 1964
Quantity
Basic Unit
Symbol
Length
Meter
m
Mass
Kilogram
kg
Time
Second
s
Electric current
Ampere
A
Termodynamic
Temperature
Kelvin
k
Luminous
intensity
candela
cd
One great advantage of the SI unit is that it uses
prefixes based on the power of 10 to relate
larger and smaller units to the basic unit.
Multiplier
Prefix
Symbol
1012
Tera
T
109
Giga
G
106
Mega
M
103
Kilo
k
10-3
Milli
m
10-6
Micro
10-9
Nano
n
10-12
Pico
p
10-15
Femto
f
10-18
Atto
a
100
Current
Electric current is the time rate of change of charge,
measured in amperes (A)
1A=1C/s
Direct current (dc): current that remains constant with
time.
Alternating current (ac): current that varies sinusodally
with time.
dq
i
dt
i = current in ampere
q= charge in coulomb
t = time in second
Current
direct current
Alternating current
exponential current
Damped current
Voltage
Voltage (potential difference): energy required to move a
unit charge through an element, measured in volts (V).
An honour of Italian Physician, Alessandro Antonio
Anastasio Volta in 18 century.
One voltage equal to one Joule per coulomb.
dw
v
dq
v = voltage in volt
w = energy in Joule
q = charge in coulomb
Power
Power is the time rate of expending or absorbing
energy, measured in watts (W)
Power absorbed = - Power supplied
dw
p
dt
p  vi
p = power in watt (W=J/s)
w = energy in joule (J)
t = time in second (s)
v = voltage in volt (V)
I = current in ampere (A)
Energy
Laws of conservation of energy: sum of
power absorbed by electric circuit was
zero. Otherwords, All supplied energy on
one circuit was equal to absorbed energy.
Energy is the capacity to do work,
measured in joules (J).
t
t
t0
t0
w   p dt   (vi) dt
Basic Circuit Elements
One element on simple circuit is a
mathematical model for electric apparatus
that have two terminals.
Basic Circuit
Elements
Active Elements
Could supplied power to
circuits
Example : Voltage and
Current source
Passive Elements
Only could absorb
power
Example : resistor,
inductance, capasitance,
diod and etc.
Voltage and Current Source
Independent source establishes a voltage or
current in a circuit without relying on voltages or
currents elsewhere in the circuit.
Dependent source establishes a voltage or
current whose value depends on a value of a
voltage or current elsewhere in the circuit.
Ideal voltage source is a circuit element that
maintains prescribed voltage across its terminals
regardless of the current flowing in those
terminals.
Ideal current source is a circuit element that
maintains a prescribed current through its
terminals regardless of the voltage across in
those terminals.
Independent source
Voltage
Current
Dependent source
dependent voltageControlled voltage
source
dependent voltagecontrolled current source
dependent currentcontrolled voltage
source
dependent currentcontrolled current source
Ohm’s law
Ohm’s law states that the voltage V
across a resistor is directly
proportional to the current i flowing
through the resistor.
An honour of German Physician, George
Simon Ohm in 19 century.
Thus, equation becomes
V  IR
R = resistance measured in ohm (  )
Conductance is the ability of an
element to conduct electric circuit; it is
measured in siemens (S)
1
G
R
Kirchhoff’s laws were first introduced
in 1847 by German physicist Gustav
Robert Kirchhoff.
He introduced two laws :
1. Kirchhoff’s Current law (KCL)
2. Kirchhoff’s Voltage law (KVL)
Kirchhoff’s Current law (KCL)
KCL states that the algebraic sum
of currents entering a node (or a
closed boundary) is zero.
Mathematically, KCL implies that
N
i
n 1
n
0
entering current=leaving current
By this law, currents entering a node
may be regarded as positive, while
currents leaving the node may be
taken as negative.
Kirchhoff’s Voltage law (KVL)
KVL states that the algebraic sum
of all voltages around a closed
path (or loop) is zero.
Expressed mathematically,
KVL states that
M
v

0
m
m 1
Circuit Model
Circuit model is mathematic
model that described electrical
system.
An ideal circuit component is a
mathematically model of an actual
electric component that connect
series or parallel.
Series Circuit
Two element connect series if:
1. This two circuit element only
have one point connection.
2. Point between this two element
wasn’t connected with other
current supply.
Example : Series circuit
Parallel Circuit
Two element, branch or
sequence are parallel if
connect with two point.
Example : Parallel circuit
Series-Parallel circuit
combination
Series-Parallel circuit could
combine to have one complex
sequence circuit.
Example : Series-Parallel circuit
combination
CIRCUIT WITH DEPENDENT
SOURCE
By using Kirchhoff’s Voltage
Law at first loop,
500  5 i  20 i0
(1)
By using Kirchhoff’s Current
law at second loop,
i0  i  5 i
i0  6i
(2)
Solve equation (1) and (2)
i  4 A
i0  24 A
By using Ohm’s law at 20Ω
resistor
v0  480V
Question 1
a)
va  (1)(8)  8V
2
p8 
b)
(8)
2

 (1) (8)  8W
8
ib  (50)(0.2)  10 A
p0.2  (50) (0.2)  500W
2
c)
vc  (1)(20)  20V
(20)
2

 (1) (20)  20W
20
2
p20
d)
 50
id 
 2 A
25
2
p 25
(50)
2

 (2) (25)  100W
25
Question 2
Calculate I and V0
Answer:
6  18  I  2 I  3I  0
6 I  12
I  2A
V0  5I
 (5)( 2)  10V
Question 3
Calculate current value for this
circuit by using Kirchhoff
Volatage law.
30
120V
30V
15
Current flows clockwise
direction
 120  30 I  30  15I  0
45I  90
I  2A
Current flows anti-clockwise
direction
120  15I  30  30 I  0
45I  90
I  2 A
Voltage at resistor:
V30  IR  (2)(30)  60V
V15  IR  (2)(15)  30V
Power absorbed by resistor :
p30  VI  I R
2
 (60)( 2)  (2) (30)
 120W
2
p15  VI  I R
2
 (30)( 2)  (2) (15)
 60W
2
Question 4
By using Kirchhoff Voltage law
at those two loop, below
equation can be define:
10  6 is
3 is  2 i0  3 i0
Solve those two equation
is  1.67 A
i0  1A
By using Ohm’s law at 3Ω
resistor
v0  3i0  3V
Reference
Nilson And Riedel. (1996). Electric
Circuits. 7th E. Addison Wesley, Reading,
Massachusetts
Alexander and Sadiku. Fundamentals Of
Electric Circuits. 3th E. McGraw-Hill IE.