A computer is an electronic device that has the capability to manipulate information or data, store, retrieve, and process it for more useful information. It is programmable so it can responds to specific instructions or commands. There are many types of computers but the Personal Computer is the most popular because of its general usage.
Personal Computer popularly known as “PC” may vary from a desktop computer or Laptopcomputer known as Notebook .Computer can help you type documents, handle spreadsheets, accounting, database management, presentations, games, send email, surf the internet and more. you can also use it to handle spreadsheets, accounting, database management, presentations, games, and more.
- System Unit is the main body of a desktop computer which is typically consisting of a metal or plastic enclosure containing all the essential parts of the personal computer.
- Monitor is a visual display unit, which shows images generated from the video output a computer.Computer monitor nowadays have two types. The CRT (Cathode Ray Tube) monitor which is a big, like a tube television, and consume a lot of space in a table; however, it is the least expensive monitor option. The LCD (Liquid Crystal Display) monitor is thin and saves energy, but costs more.
When Choosing a monitor, most people, wants a larger monitors because it will usually have higher resolutions giving you more room to work and a larger area to immerse yourself. However larger screens will not necessarily produce a better picture, so it's worth finding a balance between these two factors that suits the budget of the user. The following factors will help you decide which monitor is a good one.
A. Resolution (e.g. 1280x800)The resolution of a screen is the number of 'pixels'(px) that make up its image. Pixels are small coloured dots that together create a full colour picture. Resolution will be written as the number of pixels in the horizontal direction by those in the vertical direction, e.g. 1280x800 would mean 1280 pixels wide by 800 pixels high.
B. Size(inches).Just like television, the size of a computer monitor is measured in inches and denotes the diagonal size of the screen. Most monitors these days are 'widescreen' which means they have a wider screen size, commonly in a 16:10 ratio (16 units wide and 10 units high).
C. Response Time (ms).A monitor with slow response time can result in a blurry image when something on the screen moves very fast.
D. Contrast Ratio (e.g. 1000:1). Contrast ratio in a monitor means the amount of contrast that can be achieved on the screen, which is measured by comparing the darkest image the screen can achieve with its lightest. So a contrast ratio of 1000:1 means that the white is 1000 times brighter than the darkest image. Low contrast ratios (<>
E. Brightness (cd/m2)The brighter the screen the more you will be able to see in a bright room, for example if the sun is shining. A value of between 300 and 500cd/m2 is a good starting point for most users.
F. Colour depth (bits)is the amount of colours a monitor can display. This could be measured in the amount of information per red green and blue channel the monitor can display.
- Mouse: also known as pointing device whose function is to detect two-dimensional motion relative to its supporting surface.
Computer Mouse has different types nowadays.
A. Mechanical Mouse-uses a rolling ball to detect movement; however, it is less expensive, but difficult to clean. It usually uses PS/2 connector.
B. Optical Mouse- This type of mouse usually uses USB connector, but there are few which use PS/2 connector. It uses an electronic eye to detect movement and is easier to clean but cost more than mechanical mouse.
C. Wireless Mouse-This is the most expensive mouse. Just like Optical mouse, It uses an electronic eye but it uses signal to connect to the computer.
- Keyboard is an input device, designed just like a typewriter keyboard. It is one of the primary ways we communicate with the computer and enter data. Just like mouse, there are many different types of keyboard such as wired, wireless, ergonomic, multimedia, and more.
- Speakers are external speakers which is commonly equipped with a low-power internal amplifier. The standard audio connectorof a computer speaker is a 3.5mm (1/8 inch) stereo jack plug often color-coded lime green (following the PC 99 standard) for computer sound cards.
- AVR (Automatic Voltage Regulator)The role of automatic voltage regulator's is to reduce the 5 volt signal to the lower voltage required by the microprocessor. Other prefers to have UPS (Uninterruptible Power Supply)which cost much than AVR but good enough because it has its own chargeable battery, enabling your computer not to shut down in case of power failure.
Other peripheral devices are the following:
1. Printer is a device which produces a hard copy. Hard copy is a permanent human-readable text or picture of documents stored in the computer. Most printers are primarily used as local peripherals, and are attached by a printer cable. New printers like Ink-jet printer and Laser printer uses a USB cable connector, while the old model, Dot-Matrix printer usually uses a serial connector.
2. Webcam: A digital camera capable of downloading images to a computer for transmission over the Internet or other network.
3. Scanner: is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image.
4. DSL (Digital Subscriber Line) Modem is a device used to connect a single computer or router to a DSL phone line, in order to use an ADSL service. Like other modems it is a type of transceiver.
SUGGESTED ACTIVITY FOR STUDENTS:
Here is the demonstration on how to connect important peripherals to the system unit
On Video: Mark Lester - Assistant, Joseph Densing - Demonstrator, Euclid Teplonuevo - On Voice over and Jomarie Cruz on Camera (All Third Year Students of Balara High School S.Y. 2009-2010)