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Pengantar Teknik Elektro
Elektronika II
Standar Kompetensi
• Mahasiswa mampu menghitung persamaan dasar dan
memahami profesi yang bisa ditekuni bidang elektronika
Rujukan
• Valery Vodovozov, Introduction to Electronic Engineering,
2010
• Alfred D. Chandler, Jr., Inventing the Electronic Century, 2005
Electric circuit
An electric circuit is an interconnection of electrical elements
linked together in a closed path so that electric current may
flow continuously
Circuit diagrams are the standard for electrical engineers
Rate of flow of charge form node a to node b
Rate of flow of charge form node b to node a
(i = current)
A direct current (dc) is a current of constant magnitude
An alternating current (ac) is a
current of varying magnitude and
direction
Voltage
Driving “force” of electrical current between two points
Vab
Voltage at terminal a with respect to terminal b
Vba
Voltage at terminal b with respect to terminal a
Vab = -Vba
Note: In a circuit, voltage is often defined relative to “ground”
Voltage
The voltage across an element is the work (energy) required to move a
-
unit of positive charge from the “ ” terminal to the “+” terminal
A volt is the potential difference
(voltage) between two points when 1
joule of energy is used to move 1
coulomb of charge from one point to
the other
Power
The rate at which energy is converted or work is performed
A watt results when 1 joule of energy is converted or used in 1 second
Circuit schematic example
Circuit elements
Resistors
Resistance (R) is the physical
property of an element that
impedes the flow of current . The
units of resistance are Ohms (Ω)
Resistivity (ρ) is the ability of a
material to resist current flow. The
units of resistivity are Ohm-meters
(Ω-m)
Example:
Resistivity of copper
1.68×10−8 Ω·m
Resistivity of glass
1010 to 1014 Ω·m
Resistors
Resistor Labels
• Wire-wound resistors have a label indicating resistance and power ratings.
• A majority of resistors have color bars to indicate their resistance magnitude.
• There are usually 4 to 6 bands of color on a resistor. As shown in the figure
below, the right most color bar indicates the resistor reliability, however, some
resistor use this bar to indicate the tolerance. The color bar immediately left
to the tolerance bar (C), indicates the multipliers (in tens). To the left of the
multiplier bar are the digits, starting from the last digit to the first digit.
Resistor value = AB 10C  tol%()
Resistors
Metric Units and Conversions
Abbreviation Means
p
n
µ
m
.
k
M
G
Multiply unit by
pico
.000000000001
nano
.000000001
micro
.000001
milli
.001
Unit
1
kilo
1,000
mega
1,000,000
giga
1,000,000,000
Or
10 -12
10 -9
10 -6
10 -3
10 0
10 3
10 6
10 9
Digital Multimeter 1
• DMM is a measuring instrument
• An ammeter measures current
• A voltmeter measures the potential
difference (voltage) between two
points
• An ohmmeter measures resistance
• A multimeter combines these
functions,
and
possibly
some
additional ones as well, into a single
instrument
Digital Multimeter 2
• Voltmeter
• Parallel connection
• Ammeter
• Series connection
• Ohmmeter
• Without any power supplied
• Adjust range (start from highest
limit if you don’t know)
Ammeter Connection
• Break the circuit so that the ammeter can be connected in series
• All the current flowing in the circuit must pass through the ammeter
• An ammeter must have a very LOW input impedance
Voltmeter Connection
• The voltmeter is connected in parallel between two
points of circuit
• A voltmeter should have a very HIGH input impedance
Ohmmeter Connection
• An ohmmeter does not function with a circuit connected to a
power supply
• Must take it out of the circuit altogether and test it separately
Resistors in Series
Rtotal=R1+R2
Rtotal=1+1=2kΩ
Resistors in Parallel
R1  R2
Rtotal 
R1  R2
1 1 1
Rtotal 
  0.5k
11 2
Exercise 1
R2  R3
Rtotal  R1 
R2  R3
1 1 3
Rtotal  1 
  1.5k
11 2
Ohm’s Law
(remember, R is in Ω
and ρ is in Ω-m)
Capacitors
Capacitors
A capacitor consists of a pair of
conductors separated by a
dielectric (insulator).
(ε indicates how penetrable a subtance is to an
electric field)
Electric charge is stored in the plates
– a capacitor can become “charged”
When a voltage exists across
the conductors, it provides the
energy to move the charge
from the positive plate to the
other plate.
Capacitors
Capacitance (C) is the ability of a material to store charge in the
form of separated charge or an electric field. It is the ratio of
charge stored to voltage difference between two plates.
Capacitance is measured in Farads (F)
Capacitors
The capacitor plate attached to the negative
terminal accepts electrons from the battery.
The capacitor plate attached to the positive
terminal accepts protons from the battery.
What happens when the light bulb is
initially connected in the circuit?
What happens if you replace the battery
with a piece of wire?
Energy storage
Work must be done by an external influence (e.g. a battery) to
separate charge between the plates in a capacitor. The charge is
stored in the capacitor until the external influence is removed and
the separated charge is given a path to travel and dissipate.
Work exerted to charge a capacitor is given by the equation:
Capacitor Variations
Axial lead
•Electrolytic
•Ceramic capacitors
–very
popular
capacitor
–small, inexpensive,
temperature stability
accuracy
Radial lead
–Aluminum, tantalum electrolytic
nonpolarized
but
and
poor
poor
–ceramic dielectric and a phenolic
coating
–often used for bypass and coupling
applications
–Tantalum electrolytic capacitor has a
larger capacitance when compared to
aluminum electrolytic capacitor
–Mostly polarized.
–Greater capacitance but poor tolerance
when compared to nonelectrolytic
capacitors.
–Bad temperature
leakage, short lives
stability,
high
Capacitor Variations
•Mylar
•Mica
–very popular, nonpolarized
–reliable,
leakage
inexpensive,
–poor temperature stability
low
–extremely accurate, low leakage
current
–constructed with alternate layers of
metal foil and mica insulation,
stacked and encapsulated
–small capacitance
–often used in high-frequency
circuits (i.e. RF circuits)
Capacitor Reading Example —I
10 104 pF=105 1012 F=107 F=0.1106 F=0.1μF
•Thus, we have a 0.1mF capacitor with ±10% tolerance.
Capacitor Reading Example —II
10 103 pF=104 1012 F=108 F=0.01106 F=0.01μF
Inductors
An inductor is a two terminal element
consisting of a winding of N turns capable
of storing energy in the form of a magnetic
field
Inductance (L) is a measure of the ability of
a device to store energy in the form of a
magnetic field. It is measured in Henries (H)
Inductors
Inductance in a cylindrical coil
μ0 = permeability of free space = 4π × 10−7 H/m
K = Nagaoka coefficient
N = number of turns
A = area of cross-section of the coil in m2
l = length of coil in m
Inductors
The magnetic field from an inductor can generate an induced
voltage, which can be used to drive current
While building the magnetic field, the inductor resists current flow
Inductors
What happens to the light bulb when the switch is closed?
What happens to the light bulb when the switch is then opened?
Series circuit example
Parallel Circuit example
Rangkaian Paralel
Rangkaian Seri
Profesi bidang Elektronika
• RnD : Polytron, pabrik pcb,
• Technical Support : peralatan instrumentasi
• Perancang IC