2. Keyboard-An input device similar to a typewriter, for the entry of text, numbers and punctuation.

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1 Computer Hardware: 1. System Unit- The main part of a personal computer. The system unit includes the chassis, microprocessor, main memory, bus, and ports, but does not include the keyboard or monitor, or any peripheral devices. 2. Keyboard-An input device similar to a typewriter, for the entry of text, numbers and punctuation. 3. Mouse-A device that controls the movement of the cursor or pointer on a display screen. There are three basic types of mice: mechanical: Has a rubber or metal ball on its underside that can roll in all directions. Mechanical sensors within the mouse detect the direction the ball is rolling and move the screen pointer accordingly. Optomechanical: Same as a mechanical mouse, but uses optical sensors to detect motion of the ball. Roger Embalsado Page 1

2 optical: Uses a laser to detect the mouse's movement. You must move the mouse along a special mat with a grid so that the optical mechanism has a frame of reference. Optical mice have no mechanical moving parts. They respond more quickly and precisely than mechanical and optomechanical mice, but they are also more expensive. Mice connect to PCs in one of several ways: Serial mice connect directly to an RS-232C serial port or a PS/2 port. This is the simplest type of connection. PS/2 mice connect to a PS/2 port. USB mice: Cordless mice aren't physically connected at all. Instead they rely on infrared or radio waves to communicate with the computer. Cordless mice are more expensive than both serial and bus mice, but they do eliminate the cord, which can sometimes get in the way. 4. Monitor - Another term for display screen. The term monitor, however, usually refers to the entire box, whereas display screen can mean just the screen. In addition, the term monitor often implies graphics capabilities. There are many ways to classify monitors. The most basic is in terms of color capabilities, which separates monitors into three classes: A. Monochrome Monitor: Monochrome monitors actually display two colors, one for the background and one for the foreground. The colors can be black and white, green and black, or amber and black. Roger Embalsado Page 2

3 B. Gray-Scale Monitor: A gray-scale monitor is a special type of monochrome monitor capable of displaying different shades of gray. C. Color Monitors: can display anywhere from 16 to over 1 million different colors. Color monitors are sometimes called RGB monitors because they accept three separate signals -- red, green, and blue. a: Cathode Ray Tube (CRT) Monitor b: Liquid Crystal Display (LCD) Monitor Roger Embalsado Page 3

4 5. Printer-A device that prints text or illustrations on paper. There are many different types of printers. In terms of the technology utilized, printers fall into the following categories: a. dot-matrix Printer: Creates characters by striking pins against an ink ribbon. Each pin makes a dot, and combinations of dots form characters and illustrations. b. Ink-Jet Printer: Sprays ink at a sheet of paper. Ink-jet printers produce high-quality text and graphics. c. Laser Printer: Uses the same technology as copy machines. Laser printers produce very high quality text and graphics. d. Line Printer: Contains a chain of characters or pins that print an entire line at one time. Line printers are very fast, but produce low-quality print. Roger Embalsado Page 4

5 e. Thermal Printer: An inexpensive printer that works by pushing heated pins against heat-sensitive paper. Thermal printers are widely used in calculators and fax machines. Printers are also classified by the following characteristics: 1. Impact or Non-Impact: Impact printers include all printers that work by striking an ink ribbon. Daisy-wheel, dot-matrix, and line printers are impact printers. Non-impact printers include laser printers and ink-jet printers. The important difference between impact and non-impact printers is that impact printers are much noisier. 2. Graphics: Some printers (daisy-wheel and line printers) can print only text. Other printers can print both text and graphics. 3. fonts : Some printers, notably dot-matrix printers, are limited to one or a few fonts. In contrast, laser and ink-jet printers are capable of printing an almost unlimited variety of fonts. Daisy-wheel printers can also print different fonts, but you need to change the daisy wheel, making it difficult to mix fonts in the same document. 6. PC Camera/webcam - A webcam is a video camera which feeds its images in real time to a computer or computer network, often via USB, ethernet or Wi-Fi. Their most popular use is the establishment of video links, permitting computers to act as videophones or videoconference stations. This common use as a camera for the web gives the webcam its name. Other popular uses include security surveillance and computer vision. Webcams are known for their low manufacturing costs and flexibility, making them the lowest cost form of videotelephony. They have also become the source of security and privacy issues, as some inbuilt webcams can be remotely activated via spyware. Roger Embalsado Page 5

6 7. Headset - A headset is a headphone combined with a microphone. Headsets provide the equivalent functionality of a telephone handset with hands-free operation. Headsets typically have only one speaker like a telephone, but also come with speakers for both ears. They have many uses including in call centers and other telephone-intensive jobs and for personal use at the computer to facilitate comfortable simultaneous conversation and typing. 8. Image Scanner - In computing, an image scanner often abbreviated to just scanner is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Common examples found in offices are variations of the desktop (or flatbed) scanner where the document is placed on a glass window for scanning. Hand-held scanners, where the device is moved by hand, have evolved from text scanning "wands" to 3D scanners used for industrial design, reverse engineering, test and measurement, orthotics, gaming and other applications. Mechanically driven scanners that move the document are typically used for large-format documents, where a flatbed design would be impractical. 9. Computer Speakers or Multimedia Speakers - are speakers external to a computer, that disable the lower fidelity built-in speaker. They often have a low-power internal amplifier. The standard audio connection is a 3.175mm (1/8 inch) stereo jack plug often colour-coded lime green (following the PC 99 standard) for computer sound cards. A plug and socket for a two-wire (signal and ground) coaxial cable that is widely used to connect analog audio and video components. Also called a "phono connector," rows of RCA sockets are found on the backs of stereo amplifier and numerous A/V products. The prong is 1/8" thick by 5/16" long. A few use an RCA connector for input. There are also USB speakers which are powered from the 5 volts at 500 milliamps provided by the USB port, allowing about 2.5 watts of output power. Roger Embalsado Page 6

7 A piece of equipment that operates in conjunction with and under the control of a central system, such as a computer or control system, but is not part of the system itself. A peripheral is a device attached to a host computer, but not part of it, and is more or less dependent on the host. It expands the host's capabilities, but does not form part of the core computer architecture. Examples are: 1. Hard Disk Drive - is a type of hard disk drive which is connected to a computer by a USB cable or other means. Modern entries into the market consist of standard SATA, IDE, or SCSI hard drives in portable disk enclosures with USB, esatap, esata, SCSI, IEEE 1394 Firewire client interfaces to connect to the host computer. 2. DVD-ROM Drive or Optical Disc Drive (ODD) - is a disk drive that uses laser light or electromagnetic waves near the light spectrum as part of the process of reading or writing data to or from optical discs. Some drives can only read from discs, but recent drives are commonly both readers and recorders. Recorders are sometimes called burners or writers. Compact discs, DVDs, and Blu-ray discs are common types of optical media which can be read and recorded by such drives. Roger Embalsado Page 7

8 3. Tape Drive - is a data storage device that reads and writes data on a magnetic tape. It is typically used for offline, archival data storage. Tape media generally has a favorable unit cost and long archival stability. 4. Jaz Drive - A Jaz drive is a small, portable hard disk drive used primarily for backing up and archiving personal computer files. The Jaz drive is sold by Iomega Corporation, the same company that developed the Zip drive. Both the Jaz drive and the disks come in two sizes, 1 GB and 2 GB. The two sizes look similar, but a 2 GB disk is not compatible with a 1 GB Jaz drive. The 2 GB Jaz drive can use both disk sizes. Internal and external Jaz drives are available. The Jaz drive uses the Small Computer System Interface ( Small Computer System Interface) and requires a SCSI controller. 5. Zip Drive - is a medium-capacity removable disk storage system, introduced by Iomega in late Originally, Zip disks launched with capacities of 100 MB, but later versions increased this to first 250 MB and then 750 MB. Roger Embalsado Page 8

9 6. Digital Camera - is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. Roger Embalsado Page 9

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