Computer Electronic Component

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Computer Electronic Component
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Electricity
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So what is Electricity? Easier - Electricity is a
form of energy produced by the movement of
electrons. Electricity is electrical power or an
electric current. This form of energy can be sent
through wires in a flow of tiny particles. It is
used to produce light and heat and to run
motors.   Harder - Electricity is a basic feature
of all matter, of everything in the universe.
Electrical force holds atoms and molecules
together. Electricity determines the structure of
every object that exists. Together with
magnetism, it causes a force called
electromagnetism, a fundamental force of the
universe.
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TYPES OF ELECTRICITY (BASED ON FLOW OF ELECTRONS)
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• Direct current, abbreviated "DC". This is the
  type of electricity that is produced by
  batteries, static, and lightning. A voltage is
  created, and possibly stored, until a circuit is
  completed. When it is, the current flows
  directly, in one direction.

An idealized 12 V DC current. The voltage is
considered positive because its potential
ismeasured relative to ground or the
zero-potential default state of the earth.(This
diagram drawn to the same scale as the AC diagram
below.)
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• Alternating current, or "AC". This is the
  electricity that you get from your house's wall
  and that you use to power most of your electrical
  appliances. Alternating current is harder to
  explain than direct current. The electricity is
  not provided as a single, constant voltage, but
  rather as a sinusoidal (sine) wave that over time
  starts at zero, increases to a maximum value,
  then decreases to a minimum value, and repeats. A
  representation of an alternating current's
  voltage over time is shown in the diagram below.

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The most common AC waveform is a sine (or
sinusoidal) waveform.
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Why does standard electricity come only in the
form of alternating current? There are a number
of reasons, but one of the most important is that
a characteristic of AC is that it is relatively
easy to change voltages from one level to another
using a transformer, while transformers do not
work for DC.
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Another reason is that it may be easier to
mechanically generate alternating current
electricity than direct current. PCs use only
direct current, which means that the alternating
current provided by your utility must be
converted to direct current before use. This is
the primary function of your power supply.
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Conductors and Insulators In a conductor,
electric current can flow freely, in
an insulator it cannot. Metals such as copper
typify conductors, while most non-metallic solids
are said to be good insulators, having extremely
high resistance to the flow of charge through
them. "Conductor" implies that the outer
electrons of the atoms are loosely bound and free
to move through the material. Most atoms hold on
to their electrons tightly and are insulators. In
copper, the valence electrons are essentially
free and strongly repel each other. Any external
influence which moves one of them will cause a
repulsion of other electrons which propagates,
"domino fashion" through the conductor. Simply
stated, most metals are good electrical
conductors, most nonmetals are not. Metals are
also generally good heat conductors while
nonmetals are not.
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• Here are a few common examples of conductors and
  insulators
• Conductors
• silver
• copper
• gold
• aluminum
• iron
• steel
• brass
• bronze
• mercury
• graphite
• dirty water
• Concrete
• Insulators
• glass
• rubber

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It must be understood that not all conductive
materials have the same level of conductivity,
and not all insulators are equally resistant to
electron motion. Electrical conductivity is
analogous to the transparency of certain
materials to light materials that easily
"conduct" light are called "transparent," while
those that don't are called "opaque." However,
not all transparent materials are equally
conductive to light. Window glass is better than
most plastics, and certainly better than "clear"
fiberglass. So it is with electrical conductors,
some being better than others.
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For instance, silver is the best conductor in the
"conductors" list, offering easier passage for
electrons than any other material cited. Dirty
water and concrete are also listed as conductors,
but these materials are substantially less
conductive than any metal. It should also be
understood that some materials experience changes
in their electrical properties under different
conditions. Glass, for instance, is a very good
insulator at room temperature, but becomes a
conductor when heated to a very high temperature.
Gases such as air, normally insulating materials,
also become conductive if heated to very high
temperatures. Most metals become poorer
conductors when heated, and better conductors
when cooled. Many conductive materials become
perfectly conductive (this is called
superconductivity) at extremely low temperatures.
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While the normal motion of "free" electrons in a
conductor is random, with no particular direction
or speed, electrons can be influenced to move in
a coordinated fashion through a conductive
material. This uniform motion of electrons is
what we call electricity, or electric current. To
be more precise, it could be called dynamic
electricity in contrast to static electricity,
which is an unmoving accumulation of electric
charge. Just like water flowing through the
emptiness of a pipe, electrons are able to move
within the empty space within and between the
atoms of a conductor. The conductor may appear to
be solid to our eyes, but any material composed
of atoms is mostly empty space! The liquid-flow
analogy is so fitting that the motion of
electrons through a conductor is often referred
to as a "flow."
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A noteworthy observation may be made here. As
each electron moves uniformly through a
conductor, it pushes on the one ahead of it, such
that all the electrons move together as a group.
The starting and stopping of electron flow
through the length of a conductive path is
virtually instantaneous from one end of a
conductor to the other, even though the motion of
each electron may be very slow. An approximate
analogy is that of a tube filled end-to-end with
marbles
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The tube is full of marbles, just as a conductor
is full of free electrons ready to be moved by an
outside influence. If a single marble is suddenly
inserted into this full tube on the left-hand
side, another marble will immediately try to exit
the tube on the right. Even though each marble
only traveled a short distance, the transfer of
motion through the tube is virtually
instantaneous from the left end to the right end,
no matter how long the tube is. With electricity,
the overall effect from one end of a conductor to
the other happens at the speed of light a swift
186,000 miles per second!!! Each individual
electron, though, travels through the conductor
at a much slower pace.
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If we want electrons to flow in a certain
direction to a certain place, we must provide the
proper path for them to move, just as a plumber
must install piping to get water to flow where he
or she wants it to flow. To facilitate this,
wires are made of highly conductive metals such
as copper or aluminum in a wide variety of sizes.
Remember that electrons can flow only when they
have the opportunity to move in the space between
the atoms of a material. This means that there
can be electric current only where there exists a
continuous path of conductive material providing
a conduit for electrons to travel through. In the
marble analogy, marbles can flow into the
left-hand side of the tube (and, consequently,
through the tube) if and only if the tube is open
on the right-hand side for marbles to flow out.
If the tube is blocked on the right-hand side,
the marbles will just "pile up" inside the tube,
and marble "flow" will not occur. The same holds
true for electric current the continuous flow of
electrons requires there be an unbroken path to
permit that flow. Let's look at a diagram to
illustrate how this works
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A thin, solid line (as shown above) is the
conventional symbol for a continuous piece of
wire. Since the wire is made of a conductive
material, such as copper, its constituent atoms
have many free electrons which can easily move
through the wire. However, there will never be a
continuous or uniform flow of electrons within
this wire unless they have a place to come from
and a place to go. Let's add an hypothetical
electron "Source" and "Destination"
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Now, with the Electron Source pushing new
electrons into the wire on the left-hand side,
electron flow through the wire can occur (as
indicated by the arrows pointing from left to
right). However, the flow will be interrupted if
the conductive path formed by the wire is broken
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Since air is an insulating material, and an air
gap separates the two pieces of wire, the
once-continuous path has now been broken, and
electrons cannot flow from Source to Destination.
This is like cutting a water pipe in two and
capping off the broken ends of the pipe water
can't flow if there's no exit out of the pipe. In
electrical terms, we had a condition of
electrical continuity when the wire was in one
piece, and now that continuity is broken with the
wire cut and separated. If we were to take
another piece of wire leading to the Destination
and simply make physical contact with the wire
leading to the Source, we would once again have a
continuous path for electrons to flow. The two
dots in the diagram indicate physical
(metal-to-metal) contact between the wire pieces
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Now, we have continuity from the Source, to the
newly-made connection, down, to the right, and up
to the Destination. This is analogous to putting
a "tee" fitting in one of the capped-off pipes
and directing water through a new segment of pipe
to its destination. Please take note that the
broken segment of wire on the right hand side has
no electrons flowing through it, because it is no
longer part of a complete path from Source to
Destination. It is interesting to note that no
"wear" occurs within wires due to this electric
current, unlike water-carrying pipes which are
eventually corroded and worn by prolonged flows.
Electrons do encounter some degree of friction as
they move, however, and this friction can
generate heat in a conductor. This is a topic
we'll explore in much greater detail later.
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Static and Dynamic
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 Definition - In general, dynamic means energetic, capable of action and/or change, or forceful, while static means stationary or fixed. In computer terminology, dynamic usually means capable of action and/or change, whilestatic means fixed. Both terms can be applied to a number of different types of things, such as programming languages (or components of programming languages), Web pages, and application programs.When a Web page is requested (by a computer user clicking a hyperlink or entering a URL), the server where the page is stored returns the HTMLdocument to the user's computer and the browser displays it.
dynamic and static



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On a static Web page, this is all that happens.
The user may interact with the document through
clicking available links, or a small program
(an applet) may be activated, but the document
has no capacity to return information that is not
pre-formatted. On a dynamic Web page, the user
can make requests (often through a form) for data
contained in a database on the server that will
be assembled on the fly according to what is
requested.
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For example the user might want to find out
information about a theatrical performance, such
as theater locations and ticket availability for
particular dates. When the user selects these
options, the request is relayed to the server
using an intermediary, such as an Active Server
Page (ASP) scriptembedded in the page's HTML. The
intermediary tells the server what information to
return. Such a Web page is said to be dynamic. A
set of HTML capabilities are provided that help a
designer create dynamic Web pages. This set of
capabilities is generally known as dynamic HTML.
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There are dynamic and static programming
languages. In a dynamic language, such
as Perl or LISP, a developer can
create variables without specifying their type.
This creates more flexible programs and can
simplifyprototyping and some object-oriented codin
g. In a static programming language, such
as C or Pascal, a developer must declare the type
of each variable before the code is compiled,
making the coding less flexible, but also less
error-prone.
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Digital vs. Analog Signal
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What is a Signal? Plain and simple, a signal is
the transmission of data. We deal with signals
constantly during the span of our lives. We
interact with signals from music, power lines,
telephones, and cellular devices. This means the
use of antennas, satellites, and of course wires.
In "computer land" signals are very important.
Anyone that uses a computer should know how the
machine transforms data into signals that other
computers and devices can understand. In many
cases, knowing how signals work will help you
solve some kind of technical problem over the
span of your life. 
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Analog Waveforms Analog signals were first used
in the 1800's. They were used in conjunction with
copper telephone lines to transmit conversations.
This involved using 2 conductors for each line
(send and receive). As technology progressed an
increasing number of people started using the
telephone making analog signals too expensive and
troublesome to maintain. This was due to the way
the analog signals work. See the images below 

Now notice that the signal has picked up "noise."
Noise is simply an unwanted electrical or
electromagnetic energy that degrades the quality
of a signal. The signal level crosses over the X
and Y limits and has now become degraded and hard
for the device on the receiving end to interpret.
Noise is sometimes called "distortion" or
"clipping." 
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As signals travel across a wire, certain factors
will add more "noise" to the signal. These
factors can include air conditioning units,
fluorescent lights, magnetic fields, etc. There
are methods of separating or "filtering" noise
from analog signals. However, most of these
methods are not accurate, or are devices that
transform the signals from analog to digital and
back to analog. For these reasons, the use of
digital signaling is used to provide a better
delivery method. 
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Digital Waveforms The physics of digital signals
are different than analog signals because they
are discrete waveforms. Between the minimum X and
the maximum Y, there is a limit on how high the
voltage will increase or decrease. See the images
below 
Notice that the signal takes 2 basic
forms on (with a value of 1) and off (with a
value or 0). Obviously digital signals are more
complicated that this, but being an article on
the basics of signals, you get the general idea.
Notice that the signal is very uniform in
composition. 
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Here, we see the main advantage of digital over
analog. Since the signal is very uniform, noise
has not severely altered its shape or amplitude.
The digital signal shows a far less change to the
actual waveform than the previous analog signal.
They are both shown below for a close comparison. 
 

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What Does This Have To Do With Computers? Compute
rs use digital signals to send and receive data.
Although digital signals can only be in the state
1 (on) and 0 (off), complicated combinations of
these two values are used to send/receive data.
Think of this example Using only binary
(values 1 and 0), we can create a string of
values that is interpreted by a computer to be
something more meaningful. For instance, the
value 11000110 00110101 10010011 00101101 is
interpreted to equal 198.53.147.45 in decimal
format. 
Conclusion In conclusion, the strength of using
a digital system over analog is clear. Digital
signals are easier to transmit and offer less
room for errors to occur. This leads to accurate
data transmission that in turn leads to faster
transmission rates and better productivity.
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Resistor A resistor is a two-terminal electronic
component that opposes an electric current by
producing a voltage drop between its terminals in
proportion to the current. Resistors are used as
part of electrical networks and electronic
circuits. The mathematical relationship between
the electrical resistance (R) of the resistor,
the voltage drop (V) across the resistor, and the
current (I) flowing through the resistor is
expressed by the following equation, known as
Ohm's law V IR.
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Colour code How can the value of a resistor be
worked out from the colours of the bands? Each
colour represents a number according to the
following scheme The first band on a resistor is
interpreted as the FIRST DIGIT of the resistor
value. For the resistor shown below, the first
band is yellow, so the first digit is 4
Number Colour
0 black
1 brown
2 red
3 orange
4 yellow
5 green
6 blue
7 violet
8 grey
9 white
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Ohms Law George Ohms (1789 - 1854) found that
Current flowing through a component is related to
its Resistance and the Voltage across it. He
produced the formula- Voltage(in volts)
Current (in amps) x Resistance (in ohms)  V I
x R        I V/R       R V/I
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The second band gives the SECOND DIGIT. This is a
violet band, making the second digit 7. The third
band is called the MULTIPLIER and is not
interpreted in quite the same way. The multiplier
tells you how many noughts you should write after
the digits you already have. A red band tells you
to add 2 noughts. The value of this resistor is
therefore 4 7 0 0 ohms, that is, 4 700   , or
4.7  . Work through this example again to
confirm that you understand how to apply the
colour code given by the first three bands. The
remaining band is called the TOLERANCE band. This
indicates the percentage accuracy of the resistor
value. Most carbon film resistors have a
gold-coloured tolerance band, indicating that the
actual resistance value is with or - 5 of the
nominal value. Other tolerance colours are
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Tolerance Colour
1 brown
2 red
5 gold
10 silver
When you want to read off a resistor value, look
for the tolerance band, usually gold, and hold
the resistor with the tolerance band at its right
hand end. Reading resistor values quickly and
accurately isn't difficult, but it does take
practice!
Axial-lead resistors on tape. The tape is removed
during assembly before the leads are formed and
the part is inserted into the board.
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Three carbon composition resistors in a 1960s
valve radio. Electronic components resistor
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Capacitor . A capacitor (formerly known as
condenser) is a passive electronic component
consisting of a pair of conductors separated by a
dielectric (insulator). When there is a potential
difference (voltage) across the conductors a
static electric field develops in the dielectric
that stores energy and produces a mechanical
force between the conductors. An ideal capacitor
is characterized by a single constant value,
capacitance, measured in farads. This is the
ratio of the electric charge on each conductor to
the potential difference between them. Capacitors
are widely used in electronic circuits for
blocking direct current while allowing
alternating current to pass, in filter networks,
for smoothing the output of power supplies, in
the resonant circuits that tune radios to
particular frequencies and for many other
purposes.
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The effect is greatest when there is a narrow
separation between large areas of conductor,
hence capacitor conductors are often called
"plates", referring to an early means of
construction. In practice the dielectric between
the plates passes a small amount of leakage
current and also has an electric field strength
limit, resulting in a breakdown voltage, while
the conductors and leads introduce an equivalent
series resistance
Capacitor Capacitor
Modern capacitors, by a cm rule Modern capacitors, by a cm rule
Type Passive
Invented Ewald Georg von Kleist (October 1745)
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A typical electrolytic capacitor
Electronic symbol

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• Capacitor types
• Metal film Made from high quality polymer foil
  (usually polycarbonate, polystyrene,
  polypropylene, polyester (Mylar), and for high
  quality capacitors polysulfone), with a layer of
  metal deposited on surface. They have good
  quality and stability, and are suitable for timer
  circuits. Suitable for high frequencies.
• Mica Similar to metal film. Often high voltage.
  Suitable for high frequencies. Expensive.
• Paper Used for high voltages.
• Glass Used for high voltages. Expensive. Stable
  temperature coefficient in a wide range of
  temperatures.
• Ceramic Chips of altering layers of metal and
  ceramic. Depending on their dielectric, whether
  Class 1 or Class 2, their degree of
  temperature/capacity dependence varies. They
  often have (especially the class 2) high
  dissipation factor, high frequency coefficient of
  dissipation, their capacity depends on applied
  voltage, and their capacity changes with aging.
  However they find massive use in common
  low-precision coupling and filtering
  applications. Suitable for high frequencies.

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• Electrolytic Polarized. Constructionally similar
  to metal film, but the electrodes are made of
  aluminium etched to acquire much higher surfaces,
  and the dielectric is soaked with liquid
  electrolyte. They suffer from high tolerances,
  high instability, gradual loss of capacity
  especially when subjected to heat, and high
  leakage. Special types with low equivalent series
  resistance are available. Tend to lose capacity
  in low temperatures. Can achieve high capacities.
• Tantalum Like electrolytic. Polarized. Better
  performance with higher frequencies. High
  dielectric absorption. High leakage. Have much
  better performance in low temperatures.
• Supercapacitors Made from carbon aerogel, carbon
  nanotubes, or highly porous electrode materials.
  Extremely high capacity. Can be used in some
  applications instead of rechargeable batteries.

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Energy storage A capacitor can store electric
energy when disconnected from its charging
circuit, so it can be used like a temporary
battery. Capacitors are commonly used in
electronic devices to maintain power supply while
batteries are being changed. (This prevents loss
of information in volatile memory.) Conventional
electrostatic capacitors provide less than 360
joules per kilogram of energy density, while
capacitors using developing technologies can
provide more than 2.52 kilojoules per
kilogram22. In car audio systems, large
capacitors store energy for the amplifier to use
on demand. Also for a flash tube a capacitor is
used to hold the high voltage. In ceiling fans,
capacitors play the important role of storing
electrical energy to give the fa
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Transistor
Assorted transistors. A transistor is a
semiconductor device that uses a small amount of
voltage or electrical current to control a larger
change in voltage or current. Because of its fast
response and accuracy, it may be used in a wide
variety of applications, including amplification,
switching, voltage stabilization, signal
modulation, and as an oscillator. The transistor
is the fundamental building block of both digital
and analog circuitsthe circuitry that governs
the operation of computers, cellular phones, and
all other modern electronics. Transistors may be
packaged individually or as part of an integrated
circuit chip, which may hold thousands of
transistors in a very small area
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• Types
• Transistors are categorized by
• Semiconductor material germanium, silicon,
  gallium arsenide, silicon carbide
• Structure BJT, JFET, IGFET (MOSFET), IGBT,
  "other types"
• Polarity NPN, PNP, N-channel, P-channel
• Maximum power rating low, medium, high
• Maximum operating frequency low, medium, high,
  radio frequency (RF), microwave (The maximum
  effective frequency of a transistor is denoted by
  the term fT, an abbreviation for "frequency of
  transition." The frequency of transition is the
  frequency at which the transistor yields unity
  gain).
• Application switch, general purpose, audio, high
  voltage, super-beta, matched pair
• Physical packaging through hole metal, through
  hole plastic, surface mount, ball grid array
• Thus, a particular transistor may be described
  as silicon, surface mount, BJT, NPN, low power,
  high frequency switch.

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Usage In the early days of transistor circuit
design, the bipolar junction transistor (or BJT)
was the most commonly used transistor. Even after
MOSFETs became available, the BJT remained the
transistor of choice for digital and analog
circuits because of their ease of manufacture and
speed. However, the MOSFET has several desirable
properties for digital circuits, and major
advances in digital circuits have pushed MOSFET
design to state-of-the-art. MOSFETs are now
commonly used for both analog and digital
functions.
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Computers The "first generation" of electronic
computers used vacuum tubes, which generated
large amounts of heat and were bulky, and
unreliable. The development of the transistor was
key to computer miniaturization and reliability.
The "second generation" of computers, through the
late 1950s and 1960s, featured boards filled with
individual transistors and magnetic memory cores.
Subsequently, transistors, other components, and
their necessary wiring were integrated into a
single, mass-manufactured component the
integrated circuit. Transistors incorporated into
integrated circuits have replaced most discrete
transistors in modern digital computers.
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Close-up of a transistor on a mother board

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Group members Maricris Arahan Rochelle
Babriera Desarie Barbuco Jerome Barrera Elaine
Bautista