BPC 101AA
The Pearson Custom Program for CIS,
BPC101AA, Introduction to Computers I,
Phoenix College; Copyright 2011 by
Pearson Learning Solutions

IDENTIFYING COMPUTER
COMPONENTS and THEIR FUNCTIONS
CHAPTER 2

IDENTIFYING BASIC INPUT and
OUTPUT COMPONENTS


Cathode Ray Tube (CRT)

On older computers

Uses a glass picture tube, similar to picture tubes in older televisions

Liquid Crystal Display (LCD)

Uses a fluorescent light behind a flat panel


Electrical charges make picture elements, or pixels
The number of pixels per inch displayed on the screen determines the resolution, or level of detail
 More pixels per inch = higher resolution

 A device that controls a pointer on the screen

Mouse with a rubber ball

The rubber ball presses against 2 rollers that are perpendicular to each other

This action allows the pointer to move according to left-to-right position and the up-and-down position
 Optical mouse

Uses reflected beams of light instead of rollers

Thumb mouse

The user moves a track ball directly to control the pointer
 See Table 2 on page 51 for mouse instructions
 Practice using the mouse on pages 52 - 53


Pointing stick

A small knob that responds to sideways pressure

Touch pad

A small, rectangular, flat area that senses the position of your finger when you touch it

 Each keystroke is converted to a binary number that the computer understands

Function keys at the top can be programmed to perform special functions

Control Key, Alternate Key, Shift Key

Used in combination with other keys for special commands
 Num Lock Key

A key that toggles the numeric keys’ function between the navigation arrows and numbers

Control, Alt, Delete Keys

Brings up a dialog box that enables you to close the program if it is not responding


Disks – Media used to store information using magnetic methods
 Discs – Media used to store information using optical methods

Compact disc (CD) – Media used to store information as binary numbers (burning a pit for 0 and an unmarked surface, land, for 1)

Read-only drives – reads data on a disc, but can’t alter or write data on a blank disc
 Writable drives – can write to writable discs


CD (compact disc)

CD-ROM: read-only memory

CD-R: blank disc that can be recorded on

CD-RW: can be written to and erased many times

DVD (digital video disc)


DVD-ROM: read-only that can be on 2 different layers and on both sides of the disc
DVD-R: can be written on once

DVD-RW: can be written on and erased many times

BLU-RAY – ability to store 25 gigabytes on a single-layer disc and 50 gigabytes on a double-layer disc


BD-ROM: read-only
BD-R: write once

BD-RE: erased and recorded many times


A type of memory that is not as fast as RAM, but does not require constant power

Compact flash cards – used in expensive cameras

Secure Digital (SD) cards & MicroSD cards – used in cameras, cell phones, smartphones, PDA’s

Flash drives, Thumb drives, USB drives – transports files from computer to computer and plugs into a USB port

Flash hard drives – used in notebook computers and don’t use as much energy as magnetic hard drives


All computers come with an internal hard drive, which is the main storage unit in the computer

External hard drives are additional storage when the internal drive is full and to backup important data files.

 Impact printer – typewriter technology in which a metal rod struck an ink-fused ribbon, and the impact transferred the ink to the paper to make a dot.

Dot matrix printer – produces patterns of dots that form text characters.

Laser printer – transferring powdered ink to paper, then heating the ink to make it stick to the paper.

Toner – powdered ink that is melted into the paper
 Ink-jet printer – liquid ink that is directed to the paper using electric fields. Four colors (black, magenta, cyan, yellow) combine to produce all the other colors.


Speakers are used to play music, videos, sound effects, speaking content of documents

External speakers

Monitors with built-in speakers

Subwoofer – a large speaker to play low bass notes
 Speakers inside the computer’s system unit

To alert the user of a hardware problem


Microphones pick up sounds and convert them to analog signals

The computer uses A to D converter to change the sounds into binary numbers

Voice recognition – computer programs that translate what you say into text for a document or e-mail

IDENTIFYING SPECIALIZED INPUT
DEVICES


Gamepad – a specialized input device to control the action in a computerized game

Joystick – a game controller that uses a rotating ball inside the case

Nintendo Wii – a wireless controller that enables you to play golf, tennis, the guitar, etc.


Uses light-sensitive detectors that convert the image into electrical signals and fed into an A to D converter

Megapixels (millions of pixels) – the higher number of megapixels means better resolution and larger picture sizes when the image is printed

1,280 x 960 = 1.2-megapixel image

4,000 x 3,000 = 12-megapixel image


Docking station – a place where the camera sits to transfer images to the computer

Flash memory or SD cards – removed from the camera and placed in a card reader that is connected by a wire to the computer to transfer images


Point-and-shoot camera – smallest and least expensive with automatic focus and shutter speeds

Digital single lens reflex (DSLR) camera – more expensive and larger. The photographer controls the settings.


Frames per second – the number of pictures taken by a digital video camera in one second.

It takes 30 frames per second to simulate smooth motion

It takes 15 frames per second for transmission over the
Internet

Web cams – video cameras that are attached to a computer for videoconferencing or monitoring

 Scanners convert an image into digital data so a picture can be input into a computer

Flatbed scanner – a document is placed on a pane of glass and a fluorescent lamp travels the length of the document.
The reflected light converts to numbers using an A to D converter

Document scanner – uses a stationary lamp and the paper moves past the lamp. Used when many sheets of paper need to be scanned.

Optical character recognition (OCR) program – a computer program that recognizes the image and converts it to ASCII or Unicode number.


Used by architects, mechanical engineers, photographers, and animation artists to create drawings and process photographs


A narrow beam of light and sensor that converts the flickering reflection into binary numbers the computer can read.

They are used in conjunction with a database for pricing and inventory control for objects such as groceries, clothes, music CDs, etc.


A device that uses radio frequencies to remotely retrieve data

An example is in cars on toll highways. An
RFID device is attached to the windshield and the signal is read to deduct the toll amount from the driver’s account.


Monitors that act as input devices

Used in some stores to allow customers to check out

Stylus – a penlike device that is used to tap the screen


Sensor – detects the status of something and responds to changes in a predictable manner by producing an electric signal

Alarm systems

Probes – sensors that explore hard to access places

Oxygen sensor in the exhaust pipe of a car, probes that sense the movement of the earth


Wireless devices used for appliances such as music
CD players, TVs, etc.

Infrared light – an invisible light that transmits the binary number to the appliance. The remote must be pointed to the infrared sensor on the appliance.

Radio waves – waves that transmit the binary number to the appliance. The waves spread out in all directions and do not have to be pointed at the appliance.


Passwords

Swipe cards

Biometric device – matches a user’s biological information such as fingerprint or retinal scan with patterns stored in a database to identify authorized users.


Adaptive computer devices – for use by people with special needs

Miniature keyboards

Keyboards with tactile surfaces

One-handed keyboards