Resistors

Function

Resistors restrict the flow of electric current, for example a resistor is placed in series with a light-emitting diode (LED) to limit the current passing through the LED.

Connecting and soldering

Resistors may be connected either way round. They are not damaged by heat when soldering.

Resistor values - the resistor colour code

Resistance is measured in ohms, the symbol for ohm is an omega Ώ. 1 Ώ is quite small so resistor values are often given in k Ώ and M Ώ. 1 k Ώ = 1000 Ώ 1 M Ώ = 1000000 Ώ.
Resistor values are normally shown using coloured bands. Each colour represents a number as shown in the table.
Most resistors have 4 bands:
· The first band gives the first digit.
· The second band gives the second digit.
· The third band indicates the number of zeros.
The fourth band is used to shows the tolerance (precision) of the resistor, this may be ignored for almost all circuits but further details are given.

Small value resistors (less than 10 ohm)

The standard colour code cannot show values of less than 10 Ώ. To show these small values two special colours are used for the third band: gold which means × 0.1 and silver which means × 0.01. The first and second bands represent the digits as normal.
For example:red, violet, gold bands represent 27 × 0.1 = 2.7 Ώgreen, blue, silver bands represent 56 × 0.01 = 0.56 Ώ

Tolerance of resistors (fourth band of colour code)

The tolerance of a resistor is shown by the fourth band of the colour code. Tolerance is the precision of the resistor and it is given as a percentage. For example a 390 Ώ resistor with a tolerance of ±10% will have a value within 10% of 390 Ώ, between 390 - 39 = 351 Ώ and 390 + 39 = 429 Ώ (39 is 10% of 390).
A special colour code is used for the fourth band tolerance:silver ±10%, gold ±5%, red ±2%, brown ±1%. If no fourth band is shown the tolerance is ±20%.
Tolerance may be ignored for almost all circuits because precise resistor values are rarely required.

Resistor shorthand

Resistor values are often written on circuit diagrams using a code system which avoids using a decimal point because it is easy to miss the small dot. Instead the letters R, K and M are used in place of the decimal point. To read the code: replace the letter with a decimal point, then multiply the value by 1000 if the letter was K, or 1000000 if the letter was M. The letter R means multiply by 1.
For example:
560R means 560 Ώ2K7 means 2.7 k Ώ= 2700 Ώ39K means 39 k Ώ1M0 means 1.0 M Ώ = 1000 k Ώ

Real resistor values (the E6 and E12 series)

You may have noticed that resistors are not available with every possible value, for example 22k Ώ and 47k Ώ are readily available, but 25k Ώ and 50k Ώare not!
Why is this? Imagine that you decided to make resistors every 10 Ώ giving 10, 20, 30, 40, 50 and so on. That seems fine, but what happens when you reach 1000? It would be pointless to make 1000, 1010, 1020, 1030 and so on because for these values 10 is a very small difference, too small to be noticeable in most circuits. In fact it would be difficult to make resistors sufficiently accurate.
To produce a sensible range of resistor values you need to increase the size of the 'step' as the value increases. The standard resistor values are based on this idea and they form a series which follows the same pattern for every multiple of ten.
The E6 series (6 values for each multiple of ten, for resistors with 20% tolerance) 10, 15, 22, 33, 47, 68, ... then it continues 100, 150, 220, 330, 470, 680, 1000 etc. Notice how the step size increases as the value increases. For this series the step (to the next value) is roughly half the value.
The E12 series (12 values for each multiple of ten, for resistors with 10% tolerance) 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82, ... then it continues 100, 120, 150 etc. Notice how this is the E6 series with an extra value in the gaps.
The E12 series is the one most frequently used for resistors. It allows you to choose a value within 10% of the precise value you need. This is sufficiently accurate for almost all projects and it is sensible because most resistors are only accurate to ±10% (called their 'tolerance'). For example a resistor marked 390Ώ could vary by ±10% × 390 Ώ= ±39 Ώ, so it could be any value between 351 Ώ and 429 Ώ.

Resistors in Series and Parallel

For information on resistors connected in series and parallel please see the Resistance page.

Power Ratings of Resistors

Electrical energy is converted to heat when current flows through a resistor. Usually the effect is negligible, but if the resistance is low (or the voltage across the resistor high) a large current may pass making the resistor become noticeably warm. The resistor must be able to withstand the heating effect and resistors have power ratings to show this.
Power ratings of resistors are rarely quoted in parts lists because for most circuits the standard power ratings of 0.25W or 0.5W are suitable. For the rare cases where a higher power is required it should be clearly specified in the parts list, these will be circuits using low value resistors (less than about 300 Ώ) or high voltages (more than 15V).
The power, P, developed in a resistor is given by:

P = I² × R where: P = power developed in the resistor in watts (W) or I = current through the resistor in amps (A) P = V² / R V = voltage across the resistor in volts(V) R = resistance of the resistor inohm (Ώ)

Examples:

· A 470 Ώ resistor with 10V across it, needs a power rating P = V²/R = 10²/470 = 0.21W. In this case a standard 0.25W resistor would be suitable.

· A 27 Ώ resistor with 10V across it, needs a power rating P = V²/R = 10²/27 = 3.7W. A high power resistor with a rating of 5W would be suitable.

Computers at home

The 1977 Apple II, one of the 1977 Trinity. Floppy drive pictured a model designed for the Apple III.

One early use of the term "personal computer" appeared in a November 3, 1962, New York Times article reporting John W. Mauchly's vision of future computing as detailed at a recent meeting of the American Institute of Industrial Engineers. Mauchly stated, "There is no reason to suppose the average boy or girl cannot be master of a personal computer.[11]"
The minicomputer ancestors of the modern personal computer used early integrated circuit (microchip) technology, which reduced size and cost, but they contained no microprocessor. This meant that they were still large and difficult to manufacture just like their mainframe predecessors. After the "computer-on-a-chip" was commercialized, the cost to manufacture a computer system dropped dramatically. The arithmetic, logic, and control functions that previously occupied several costly circuit boards were now available in one integrated circuit, making it possible to produce them in high volume. Concurrently, advances in the development of solid state memory eliminated the bulky, costly, and power-hungry magnetic core memory used in prior generations of computers.
There were a few researchers at places such as SRI and Xerox PARC who were working on computers that a single person could use and could be connected by fast, versatile networks: not home computers, but personal ones.
A programmable terminal called the Datapoint 2200 is the earliest known device that bears any significant resemblance to the modern personal computer[12][13]. It was made by CTC (now known as Datapoint) in 1970 and was a complete system in a small case bearing the approximate footprint of an IBM Selectric typewriter. The system's CPU was constructed from a variety of discrete components, although the company had commissioned Intel to develop a single-chip processing unit; there was a falling out between CTC and Intel, and the chip Intel had developed wasn't used. Intel soon released a modified version of that chip as the Intel 8008, the world's first 8-bit microprocessor[14]. The needs and requirements of the Datapoint 2200 therefore determined the nature of the 8008, upon which all successive processors used in IBM-compatible PCs were based. Additionally, the design of the Datapoint 2200's multi-chip CPU and the final design of the Intel 8008 were so similar that the two are largely software-compatible; therefore, the Datapoint 2200, from a practical perspective, can be regarded as if it were indeed powered by an 8008, which makes it a strong candidate for the title of "first microcomputer" as well.
Development of the single-chip microprocessor was an enormous catalyst to the popularization of cheap, easy to use, and truly personal computers. The Altair 8800, introduced in a Popular Electronics magazine article in the January 1975 issue, at the time set a new low price point for a computer, bringing computer ownership to an admittedly select market in the 1970s. This was followed by the IMSAI 8080 computer, with similar abilities and limitations. The Altair and IMSAI were essentially scaled-down minicomputers and were incomplete: to connect a keyboard or screen to them required heavy, expensive "peripherals". These machines both featured a front panel with switches and lights, which communicated with the operator in binary. To program the machine, one didn't simply power up: one first had to key in the bootstrap loader program in binary, then read in a paper tape containing a BASIC interpreter, using a massive paper-tape reader. Keying the loader required setting a bank of eight switches up or down and pressing the "load" button, once for each byte of the program, which was typically hundreds of bytes long. This was before one could begin to do any computing. (At the first West Coast Computer Faire, a three-year-old girl amused herself by flipping random switches and pressing the Load button, which were at her eye level, then moving on to the next demo. By doing so, she had inserted a random number into the location whose address was in the Program Counter, thus crashing the machine. She was followed by gasps and screams as the vendors discovered that they had to repeat the whole start-up cycle—her parents found her by heading for the commotion. The next Computer Faire banned small children. A Few years later, personal computers lost the switches and lights; thirty years later, they have memory protection, so that crashing a single program doesn't crash the machine.)[citation needed]
In 1976, the Kooro Manufacturing & Electronics Cooperative in Skopje, Macedonia produced in limited quantities, an all in one (integrated keyboard, monochrome monitor, 8 inch floppy disk drive and 16k of ram) for use by government officials. Similar in appearance to the TRS-80 Model III computer using a proprietary operating system.[15]
It was arguably the Altair computer that spawned the development of Apple, as well as Microsoft which produced and sold the Altair BASIC programming language interpreter, Microsoft's first product. The second generation of microcomputers — those that appeared in the late 1970s, sparked by the unexpected demand for the kit computers at the electronic hobbyist clubs, were usually known as home computers. For business use these systems were less capable and in some ways less versatile than the large business computers of the day. They were designed for fun and educational purposes, not so much for practical use. And although you could use some simple office/productivity applications on them, they were generally used by computer enthusiasts for learning to program and for running computer games, for which the personal computers of the period were less suitable and much too expensive. For the more technical hobbyists home computers were also used for electronics interfacing, such as controlling model railroads, and other general hobbyist pursuits.
The MOS Technology 6502 series microprocessor lead to a reduction in the expense of creating computing systems. The Commodore PET, the TRS 80, and the Apple II, also known as the 1977 Trinity by Byte magazine, are often cited as the first personal computers. Specifically, the Commodore PET, which Byte called the first [16]. The design of the Commodore PET, a single integrated machine with a built in monitor, keyboard, and datasette device, and the operating system of the Xerox Alto went on to inspire the popular Macintosh computer, by Apple.
A 1978 ad for the Apple II used the wording "Apple, the personal computer". There was no trademark symbol. Three years later, the term "personal computer" was a trademark of IBM, which had decided to invade the microcomputer market and had done it successfully; a few years later, a judge declared that "personal computer" was no longer an IBM trademark, but a generic term for any personal computer not made by Apple.

Laptop computers

A laptop computer or simply laptop, also called a notebook computer or notebook, is a small personal computer designed for mobility. Usually all of the interface hardware needed to operate the laptop, such as parallel and serial ports, graphics card, sound channel, etc., are built in to a single unit. Most laptops contain batteries to facilitate operation without a readily available electrical outlet. In the interest of saving power, weight and space, they usually share RAM with the video channel, slowing their performance compared to an equivalent desktop machine.
One main drawback of the laptop is that, due to the size and configuration of components, relatively little can be done to upgrade the overall computer from its original design. Some devices can be attached externally through ports (including via USB); however internal upgrades are not recommended or in some cases impossible, making the desktop PC more modular.

Video card

The video card - otherwise called a graphics card, graphics adapter or video adapter - processes and renders the graphics output from the computer to the computer display, also called the visual display unit (VDU), and is an essential part of the modern computer. On older models, and today on budget models, graphics circuitry tended to be integrated with the motherboard but, for modern flexible machines, they are supplied in PCI, AGP, or PCI Express format.
When the IBM PC was introduced, many existing personal computers used text-only display adapters and had no graphics capability.

Mass storage

Internals of a Winchester hard drive with the disks removed.

Mass storage devices store programs and data even when the power is off; they do require power to perform read/write functions during usage. Although semiconductor flash memory has dropped in cost, the prevailing form of mass storage in personal computers is still the electromechanical hard disk.
The disk drives use a sealed head/disk assembly (HDA) which was first introduced by IBM's "Winchester" disk system. The use of a sealed assembly allowed the use of positive air pressure to drive out particles from the surface of the disk, which improves reliability.
If the mass storage controller provides for expandability, a PC may also be upgraded by the addition of extra hard disk or optical drives. For example, DVD-ROMs, CD-ROMs, and various optical disc recorders may all be added by the user to certain PCs. Standard internal storage device interfaces are ATA, Serial ATA, SCSI, and CF+ Type II in 2005.

Main memory

A four-megabyte RAM card measuring about twenty-two by fifteen inches (56 by 38 centimeters); made for the VAX 8600 minicomputer (ca. 1986). Dual in-line package (DIP) Integrated circuits populate nearly the whole board; the RAM chips are the most common kind, and located in the rectangular areas to the left and right.

A PC's main memory (i.e., its 'primary store') is fast storage that is directly accessible by the CPU, and is used to store the currently executing program and immediately needed data. PCs use semiconductor random access memory (RAM) of various kinds such as DRAM or SRAM as their primary storage. Which exact kind depends on cost/performance issues at any particular time. Main memory is much faster than mass storage devices like hard disks or optical discs, but is usually volatile, meaning it does not retain its contents (instructions or data) in the absence of power, and is much more expensive for a given capacity than is most mass storage. Main memory is generally not suitable for long-term or archival data storage.

Central processing unit

The central processing unit, or CPU, is that part of a computer which executes software program instructions. In older computers this circuitry was formerly on several printed circuit boards, but in PC class machines, has been from the first personal computers, a single integrated circuit. Nearly all PCs contain a type of CPU known as a microprocessor. The microprocessor often plugs into the motherboard using one of many different types of socket. IBM PC compatible computers use an x86-compatible processor, usually made by Intel, AMD, VIA Technologies or Transmeta. Apple Macintosh computers were initially built with the Motorola 680x0 family of processors, then switched to the PowerPC series (a RISC architecture jointly developed by IBM, Motorola, and Apple Computer), but as of 2006, Apple has switched again, this time to x86 compatible processors.

Motherboard

The motherboard (or mainboard) is the primary circuit board within a personal computer. Many other components connect directly or indirectly to the motherboard. Motherboards usually contain one or more CPUs, supporting circuitry -- usually integrated circuits (ICs) providing the interface between the CPU memory and input/output peripheral circuits, main memory, and facilities for initial setup of the computer immediately after being powered on (often called boot firmware or, in IBM PC compatible computers, a BIOS). In many portable and embedded personal computers, the motherboard houses nearly all of the PC's core components. Often a motherboard will also contain one or more peripheral buses and physical connectors for expansion purposes. Sometimes a secondary daughter board is connected with the motherboard to provide further expandability or to satisfy space constraints.

Transistors

Function

Transistors amplify current, for example they can be used to amplify the small output current from a logic chip so that it can operate a lamp, relay or other high current device. In many circuits a resistor is used to convert the changing current to a changing voltage, so the transistor is being used to amplify voltage.

A transistor may be used as a switch (either fully on with maximum current, or fully off with no current) and as an amplifier (always partly on).

The amount of current amplification is called the current gain, symbol hFE. For further information please see the Transistor Circuits page.

Types of transistor

There are two types of standard transistors, NPN and PNP, with different circuit symbols. The letters refer to the layers of semiconductor material used to make the transistor. Most transistors used today are NPN because this is the easiest type to make from silicon. If you are new to electronics it is best to start by learning how to use NPN transistors.

The leads are labelled base (B), collector (C) and emitter (E).These terms refer to the internal operation of a transistor but they are not much help in understanding how a transistor is used, so just treat them as labels!

A Darlington pair is two transistors connected together to give a very high current gain.

In addition to standard (bipolar junction) transistors, there are field-effect transistors which are usually referred to as FETs. They have different circuit symbols and properties and they are not (yet) covered by this page.

Connecting

Transistors have three leads which must be connected the correct way round. Please take care with this because a wrongly connected transistor may be damaged instantly when you switch on.

If you are lucky the orientation of the transistor will be clear from the PCB or stripboard layout diagram, otherwise you will need to refer to a supplier's catalogue to identify the leads.

The drawings on the right show the leads for some of the most common case styles.

Please note that transistor lead diagrams show the view from below with the leads towards you. This is the opposite of IC (chip) pin diagrams which show the view from above.

Soldering

Transistors can be damaged by heat when soldering so if you are not an expert it is wise to use a heat sink clipped to the lead between the joint and the transistor body. A standard crocodile clip can be used as a heat sink.

Do not confuse this temporary heat sink with the permanent heat sink (described below) which may be required for a power transistor to prevent it overheating during operation.

Heat sinks

Waste heat is produced in transistors due to the current flowing through them. Heat sinks are needed for power transistors because they pass large currents. If you find that a transistor is becoming too hot to touch it certainly needs a heat sink! The heat sink helps to dissipate (remove) the heat by transferring it to the surrounding air. For further information please see the Heat sinks page.

Testing a transistor

Transistors can be damaged by heat when soldering or by misuse in a circuit. If you suspect that a transistor may be damaged there are two easy ways to test it:
1. Testing with a multimeter

Use a multimeter or a simple tester (battery, resistor and LED) to check each pair of leads for conduction. Set a digital multimeter to diode test and an analogue multimeter to a low resistance range.
Test each pair of leads both ways (six tests in total):

· The base-emitter (BE) junction should behave like a diode and conduct one way only.
· The base-collector (BC) junction should behave like a diode and conduct one way only.
· The collector-emitter (CE) should not conduct either way.

The diagram shows how the junctions behave in an NPN transistor. The diodes are reversed in a PNP transistor but the same test procedure can be used.

2. Testing in a simple switching circuit

Connect the transistor into the circuit shown on the right which uses the transistor as a switch. The supply voltage is not critical, anything between 5 and 12V is suitable. This circuit can be quickly built on breadboard for example. Take care to include the 10k resistor in the base connection or you will destroy the transistor as you test it!

If the transistor is OK the LED should light when the switch is pressed and not light when the switch is released.

To test a PNP transistor use the same circuit but reverse the LED and the supply voltage.

Some multimeters have a 'transistor test' function which provides a known base current and measures the collector current so as to display the transistor's DC current gain hFE.

Transistor codes

There are three main series of transistor codes used in the UK:

1. Codes beginning with B (or A), for example BC108, BC478
The first letter B is for silicon, A is for germanium (rarely used now). The second letter indicates the type; for example C means low power audio frequency; D means high power audio frequency; F means low power high frequency. The rest of the code identifies the particular transistor. There is no obvious logic to the numbering system. Sometimes a letter is added to the end (eg BC108C) to identify a special version of the main type, for example a higher current gain or a different case style. If a project specifies a higher gain version (BC108C) it must be used, but if the general code is given (BC108) any transistor with that code is suitable.

2. Codes beginning with TIP, for example TIP31A
TIP refers to the manufacturer: Texas Instruments Power transistor. The letter at the end identifies versions with different voltage ratings.

3. Codes beginning with 2N, for example 2N3053
The initial '2N' identifies the part as a transistor and the rest of the code identifies the particular transistor. There is no obvious logic to the numbering system.

Choosing a transistor

Most projects will specify a particular transistor, but if necessary you can usually substitute an equivalent transistor from the wide range available. The most important properties to look for are the maximum collector current IC and the current gain hFE. To make selection easier most suppliers group their transistors in categories determined either by their typical use or maximum power rating. To make a final choice you will need to consult the tables of technical data which are normally provided in catalogues. They contain a great deal of useful information but they can be difficult to understand if you are not familiar with the abbreviations used. The table below shows the most important technical data for some popular transistors, tables in catalogues and reference books will usually show additional information but this is unlikely to be useful unless you are experienced.

Variable Resistors

Construction

Variable resistors consist of a resistance track with connections at both ends and a wiper which moves along the track as you turn the spindle. The track may be made from carbon, cermet (ceramic and metal mixture) or a coil of wire (for low resistances). The track is usually rotary but straight track versions, usually called sliders, are also available.

Variable resistors may be used as a rheostat with two connections (the wiper and just one end of the track) or as a potentiometer with all three connections in use. Miniature versions called presets are made for setting up circuits which will not require further adjustment.

Variable resistors are often called potentiometers in books and catalogues. They are specified by their maximum resistance, linear or logarithmic track, and their physical size. The standard spindle diameter is 6mm.

The resistance and type of track are marked on the body:
4K7 LIN means 4.7 k linear track.
1M LOG means 1 M logarithmic track.

Some variable resistors are designed to be mounted directly on the circuit board, but most are for mounting through a hole drilled in the case containing the circuit with stranded wire connecting their terminals to the circuit board.

Linear (LIN) and Logarithmic (LOG) tracks

Linear (LIN) track means that the resistance changes at a constant rate as you move the wiper. This is the standard arrangement and you should assume this type is required if a project does not specify the type of track. Presets always have linear tracks.

Logarithmic (LOG) track means that the resistance changes slowly at one end of the track and rapidly at the other end, so halfway along the track is not half the total resistance! This arrangement is used for volume (loudness) controls because the human ear has a logarithmic response to loudness so fine control (slow change) is required at low volumes and coarser control (rapid change) at high volumes. It is important to connect the ends of the track the correct way round, if you find that turning the spindle increases the volume rapidly followed by little further change you should swap the connections to the ends of the track.

Rheostat

This is the simplest way of using a variable resistor. Two terminals are used: one connected to an end of the track, the other to the moveable wiper. Turning the spindle changes the resistance between the two terminals from zero up to the maximum resistance.

Rheostats are often used to vary current, for example to control the brightness of a lamp or the rate at which a capacitor charges.
If the rheostat is mounted on a printed circuit board you may find that all three terminals are connected! However, one of them will be linked to the wiper terminal. This improves the mechanical strength of the mounting but it serves no function electrically.

Potentiometer

Variable resistors used as potentiometers have all three terminals connected.
This arrangement is normally used to vary voltage, for example to set the switching point of a circuit with a sensor, or control the volume (loudness) in an amplifier circuit. If the terminals at the ends of the track are connected across the power supply then the wiper terminal will provide a voltage which can be varied from zero up to the maximum of the supply.

Presets

These are miniature versions of the standard variable resistor. They are designed to be mounted directly onto the circuit board and adjusted only when the circuit is built. For example to set the frequency of an alarm tone or the sensitivity of a light-sensitive circuit. A small screwdriver or similar tool is required to adjust presets.

Presets are much cheaper than standard variable resistors so they are sometimes used in projects where a standard variable resistor would normally be used.

Multiturn presets are used where very precise adjustments must be made. The screw must be turned many times (10+) to move the slider from one end of the track to the other, giving very fine control.

What is RAM?

RAM stands for Random Access Memory. RAM provides space for your computer to read and write data to be accessed by the CPU (central processing unit). When people refer to a computer's memory, they usually mean its RAM.

New computers typically come with at least 256 megabytes (MB) of RAM installed, and can be upgraded to 512MB or even a gigabyte or more.

If you add more RAM to your computer, you reduce the number of times your CPU must read data from your hard disk. This usually allows your computer to work considerably faster, as RAM is many times faster than a hard disk.

RAM is volatile, so data stored in RAM stays there only as long as your computer is running. As soon as you turn the computer off, the data stored in RAM disappears.

When you turn your computer on again, your computer's boot firmware (called BIOS on a PC) uses instructions stored semi-permanently in ROM chips to read your operating system and related files from the disk and load them back into RAM.

Note: On a PC, different parts of RAM may be more or less easily accessible to programs. For example, cache RAM is made up of very high-speed RAM chips which sit between the CPU and main RAM, storing (i.e., caching) memory accesses by the CPU. Cache RAM helps to alleviate the gap between the speed of a CPU's megahertz rating and the ability of RAM to respond and deliver data. It reduces how often the CPU must wait for data from main memory.

INFORMATION TECHNOLOGY

Teknologi Infromasi adalah informasi yang disampaikan melalui media elektronik, sehingga penyampaiannnya cepat. Adapun media yang sering digunakan dalam media teknologi informasi adalah Komputer, maka dalam teknologi informasi ini kami akan memperkenalkan tentang computer. Dan membahas sedikit tentang computer.
Komputer adalah media IT (Information Technology). Komputer itu sendiri tersusun atas beberapa komponen yaitu CPU (Central Processing Unit), Monitor, Keyboard, Mouse. Di dalam CPU sendiri terdapat komponen-komponen hardware. Seperti: motherboard, processor, memory, hardisk, dan lainnya.Inilah yang mengatur pusat kinerja computer. Selain terdiri perangkat utama, computer juga terdiri perangkat pelengkap atau Accessories, seperti Speaker sound, Web camera, Printer, Headset, Joystick, HD external, Wireless dan masih banyak lagi.
Meskipun computer sudah memiliki perangkat utama dan pelengkap, Akan tetapi computer tersebut belum bisa dijalankan. Karena belum memiliki Operating system atau system operasi. System operasi ini adalah berupa software yang menjalanakan computer seperti windows, linux, dan beberapa OS (Operating System) lainnya.
Beberapa komponen penting dalam Dari CPU dan fungsinya :
· Motherboard adalah induk dari computer, ini berfungsi sebagai tempat meletakkan hardware lainnya yang menjadi komponen dari CPU
· Memory, berfungsi menyimpan data sementara dan mengolah perintah menuju processor
· Processor, mengatur kinerja seluruh komponen dalam computer. Bisa dikatakan ini adalah bagian otak perintah dari computer
· Harddisk, berfungsi untuk menyimpan data secara permanent. Ini bisa dikategorikan otak memory computer
· DVD/CD/DVD-R/CD-R Drive, merupakan suatu perangkat yang berfungsi untuk menulis ataupun membaca data dari sebuah piranti yang disebut CD atau DVD
· USB port, berfungsi untuk menyambungkan CPU dengan USB Flash atau Perangkat lainnya seperti Camcoder, Digital Camera dan WebCam
· Card reader, berfungsi utnuk membaca memory stick atau yang dikenal dengan memory card

KOMPONEN AKTIF ELEKTRONIKA

1) Komponen aktif elektronika yaitu komponen yang menunjukkan hubungan tidak linear antara arus dan tegangan, jika komponen tersebut berada di dalam pengaruh medan listrik
2) Jenis-jenis Komponen aktif elektronika
· Diode → suatu bahan elektrikum yang tersusun atas 2 elektroda yaitu elektroda positif dan negatif
✗ Prinsip kerja
✔ Forward Biass (arah maju) dari anoda ke katoda
✔ Reverse Biass (arah mundur) dari katoda ke anoda
✗ Jenis-jenis Diode
✔ Dioda Zener = menstabilkan tegangan
✔ Dioda Kristal = Dioda kontak titik
✔ Light Emilting Diode (LED) = Lampu induktor
✔ Photo Diode = pencacah, penghitung
✔ Dioda Silikon = Penyearah Arus
✗ Jenis-jenis resistor yang bergantung pada suhu (TERMISTOR)
✔ NTC ( Negative Temprature Coeficient )
✔ PTC ( Positive Temprature Coeficient )
✗ Fungsi Diode
✔ Penyearah Arus
✔ Pencacah Penghitung
✔ Menstabilkan tegangan
· Transistor → rancangan komponen yang terdiri dari 3 komponen diode tipe P (+) dan
tipe N (-)
✗ Komponen penyusun transistor
✔ Emitor = Pembawa muatan
✔ Basis = Pengatur gerak pembawa muatan dari emitor ke collector
✔ collector = Pengatur gerak pembawa muatan dari emitor ke output
✗ Fungsi transistor
✔ Penguat arus
✔ Penguat tegangan atau penguat getaran
✔ Pembangkit getaran
✔ Saklar
· IC (Integrated Circuit) → merupakan kombinasi dari beberapa komponen elektronika yaitu diode, resistor, dan kapasitor kecil. JENIS IC : IC MONOLITHIK, IC HYBRIDA (IC LINEAR, IC TTL, IC CMOL)

KOMPONEN PASIF ELEKTRONIKA

1) Komponen pasif elektronika yaitu komponen yang menunjukkan hubungan linear antara arus dan tegangan, jika komponen tersebut berada di dalam pengaruh medan listrik
2) Jenis-jenis Komponen pasif elektronika
· Resistor→ suatu bahan yang dapat menghambat arus listrik
✗ Jenis-jenis resistor tetap
✔ Resistor gulungan kawat
✔ Resistor Lapisan karbon
✔ Resistor lapisan oksidasi logam
✔ Resistor komposisi karbon
✗ Jenis-jenis resistor varabel
✔ Potensiometer
➔ Geser
➔ Putar
✔ Trimmer Potensiometer (TRIMPOT)
✗ Jenis-jenis resistor yang bergantung pada suhu (TERMISTOR)
✔ NTC ( Negtive Temprature Coeficient )
✔ PTC ( Positive Temprature Coeficient )
✗ Jenis-jenis resistor yang bergantung pada cahaya (LDR)
✗ Daya Kerja resitor
✔ 1 Watt
✔ ½ Watt
✔ ¼ Watt
· Kapasitor → komponen dasar elektronika yang dapat menyimpan atau mengeluarkan muatan listrik
✗ Fungsi kapasitor
✔ Memisahkan arus AC dan arus DC
✔ Meratakan arus DC pada penyearah arus
✔ Mengontrol frekuensi pada rangkaian isolator
✔ Menyimpan muatan listrik
✗ Jenis-jenis kapasitor
✔ Kapasitor polar (ELCO)
✔ Kapasitor Non Polar (Kapasitor Kertas, Kapasitor Kermik, Kpasitor Mika, Kapasitor Poliester)
✔ Kapasitor Variabel (VARCo, TRIMMER)
✗ Kapasitas kapasitor adalah kemampuan untuk menyimpan mutan
· Transformator → komponen dasar elektronika yang dapat mengubah tegangan AC menjadi lebih tinggi atau lebih rendah

PENGETAHUAN UMUM ABOUT ELEKTONIKA

1) Elektronika adalah ilmu pengetahuan dan teknologi yang membahas aliran partikel
bermuatan di dalam Gas, di dalam hampa udara, atau di dalam semikonduktor
2) Komponen-komponen dasar elektronika, antara lain :
· Resistor
· Kapasitor
· Diode
· Induktor
· IC (Integrated Circuit)
· Transistor
1) Jenis Catuan pada elektronika
· DC merupakan singkatan dari Direct Curent adalah arus searah, arus inilah yang digunakan untuk mencatu rangkaian elektronika
· AC merupakan singkatan dari Alternative Curent yaitu arus bolak balik. Arus ini dapat digunakan untuk rangkaian elektronika dengan terlebih dahulu mengubahnya ke bentuk arus DC dengan menggunakan penyearah Arus
2) Sumber catuan yang digunakan pada perangkat elektronika
· Baterai → Primer = hanya dapat digunakan sekali dan tidak dapat diisi ulang
· AKI (Accumulator) → sekunder = Sumber catuan yang dapat diisi ulang apabila telah habis energinya
· Rangkaian Adaptor (AC→DC) = dengan mengubah arus AC → DC
3) Macam-macam Alat ukur listrik yng digunakan di elektronika
· Amperemeter → Alat yang berfungsi mengukur besar kuat arus listrik di dalam suatu rangkaian
· Voltmeter → Alat yang berfungsi mengukur beda potensial di dalam suatu rangkaian
· Ώmeter → Alat yang digunakan untuk mengukur hambatan suatu rangkian elektronika