Introduction to Computers
The hardware are the parts of the computer itself including the Central Processing Unit (CPU) and related microchips and micro-circuitry, keyboards, monitors, case and drives (hard, CD, DVD, solid-state (ssd), floppy, optical, tape, etc...). Other extra parts called peripheral components or devices include mouse, printers, modems, scanners, cameras and cards (sound, color, video) etc... Together they are often referred to as a personal computer. In the section we will cover some hardware and the more common used peripheral components as they relate to helping you learn more about computers and how they function.
External Hardware Components
Keyboard
Keyboard - The keyboard is used to type information into the computer or input information. There are many different keyboard layouts and sizes with the most common for Latin based languages being the QWERTY layout (named for the first 6 keys). The standard keyboard has 101 keys. Notebooks have embedded keys accessible by special keys or by pressing key combinations (CTRL or Command and P for example). Ergonomically designed keyboards are designed to make typing easier. Hand held devices have various and different keyboard configurations and touch screens.
Some of the keys have a special use. They are referred to as command keys. The 3 most common are the Control or CTRL, Alternate or Alt and the Shift keys though there can be more (the Windows key for example or the Command key). Each key on a standard keyboard has one or two characters. Press the key to get the lower character and hold Shift to get the upper.
Mouse

Mouse - Most modern computers today are run using a mouse controlled pointer. Generally if the mouse has two buttons the left one is used to select objects and text and the right one is used to access menus. If the mouse has one button (Mac for instance) it controls all the activity and a mouse with a third button can be used by specific software programs.
One type of mouse has a round ball under the bottom of the mouse that rolls and turns two wheels which control the direction of the pointer on the screen. Another type of mouse uses an optical system to track the movement of the mouse. Laptop computers use touch pads, buttons and other devices to control the pointer. Hand helds use a combination of devices to control the pointer, including touch screens.
Note: It is important to clean the mouse periodically, particularly if it becomes sluggish. A ball type mouse has a small circular panel that can be opened, allowing you to remove the ball. Lint can be removed carefully with a tooth pick or tweezers and the ball can be washed with mild detergent. A build up will accumulate on the small wheels in the mouse. Use a small instrument or finger nail to scrape it off taking care not to scratch the wheels. Track balls can be cleaned much like a mouse and touch-pad can be wiped with a clean, damp cloth. An optical mouse can accumulate material from the surface that it is in contact with which can be removed with a finger nail or small instrument.
Monitors

Monitors - The monitor shows information on the screen when you type. This is called outputting information. When the computer needs more information it will display a message on the screen, usually through a dialog box. Monitors come in many types and sizes. The resolution of the monitor determines the sharpness of the screen. The resolution can be adjusted to control the screen's display.
Most desktop computers use a monitor with a cathode tube or liquid crystal display. Most notebooks use a liquid crystal display monitor.
To get the full benefit of today's software with full colour graphics and animation, computers need a color monitor with a display or graphics card.
Printers

Printers - The printer takes the information on your screen and transfers it to paper or a hard copy. There are many different types of printers with various levels of quality. The three basic types of printer are; dot matrix, inkjet, and laser.
- Dot matrix printers work like a typewriter transferring ink from a ribbon to paper with a series or 'matrix' of tiny pins.
- Ink jet printers work like dot matrix printers but fires a stream of ink from a cartridge directly onto the paper.
- Laser printers use the same technology as a photocopier using heat to transfer toner onto paper.
Digital flash drives work slightly differently as they use memory cards to store information so there are no moving parts. Digital cameras also use Flash memory cards to store information, in this case photographs. Hand held devices use digital drives and many also use removable or built in memory cards.
Scanners

Scanners- Scanners allow you to transfer pictures and photographs to your computer. A scanner 'scans' the image from the top to the bottom, one line at a time and transfers it to the computer as a series of bits or a bitmap. You can then take that image and use it in a paint program, send it out as a fax or print it. With optional Optical Character Recognition (OCR) software you can convert printed documents such as newspaper articles to text that can be used in your word processor. Most scanners use TWAIN software that makes the scanner accessible by other software applications.
With advancement in technology, it is more common today to find an All-In-One machine that is a stand alone unit. This simply means that the printer, scanner and fax are combined into one device.
With advancement in technology, it is more common today to find an All-In-One machine that is a stand alone unit. This simply means that the printer, scanner and fax are combined into one device.
Digital Cameras & Camera Phones

Digital cameras allow you to take digital photographs. The images are stored on a memory chip or disk that can be transferred to your computer. Some cameras can also capture sound and video.
Camera Phones are another means of taking digital photos (and usually video as well). The majority of mobile phones in use today are camera phones. Most camera phones are simpler than separate digital cameras. The camera features are an integrated part of the the cell phones, and have limited features as compared to digital cameras.
Removable Storage and/or Disk Drives

Removable Storage and/or Disk Drives - All disks need a drive to get information off - or read - and put information on the disk - or write. Each drive is designed for a specific type of disk whether it is a CD, DVD, hard disk or floppy. Often the term 'disk' and 'drive' are used to describe the same thing but it helps to understand that the disk is the storage device which contains computer files - or software- and the drive is the mechanism that runs the disk.
Removable Storage and/or Disk Drives - All disks need a drive to get information off - or read - and put information on the disk - or write. Each drive is designed for a specific type of disk whether it is a CD, DVD, hard disk or floppy. Often the term 'disk' and 'drive' are used to describe the same thing but it helps to understand that the disk is the storage device which contains computer files - or software- and the drive is the mechanism that runs the disk.
Modem and Router

Modem - A modem is used to translate information transferred through telephone lines, cable, satellite or line-of-sight wireless.
The two major components in a small computer network are a modem (cable or DSL) and a wireless router. The router is wired to the modem, and the modem is wired to the cable company's coaxial cable or the telephone company's DSL phone line. For Internet access via satellite, the router is wired to a satellite modem.
Modem - Establish and Convert
The modem establishes and maintains the connection with the Internet provider's service and converts the signals from and to the router appropriately.
Router - Route and Keep Track
The router forwards traffic destined for the Internet to the modem, while keeping internal traffic (computer to computer, computer to printer, etc.) from leaving the network. Using assigned numbers, the router keeps track of which computer made a request to the Internet in order to send responses back to that computer only.
The two major components in a small computer network are a modem (cable or DSL) and a wireless router. The router is wired to the modem, and the modem is wired to the cable company's coaxial cable or the telephone company's DSL phone line. For Internet access via satellite, the router is wired to a satellite modem.
Modem - Establish and Convert
The modem establishes and maintains the connection with the Internet provider's service and converts the signals from and to the router appropriately.
Router - Route and Keep Track
The router forwards traffic destined for the Internet to the modem, while keeping internal traffic (computer to computer, computer to printer, etc.) from leaving the network. Using assigned numbers, the router keeps track of which computer made a request to the Internet in order to send responses back to that computer only.
A wireless router is a device that performs the functions of a router but also includes the functions of a wireless access point. A wireless router is commonly used in the home and small business, which adds other functions such as wireless printing and more..