Lesson Notes By Weeks and Term - Senior Secondary School 1

SUBJECT: INFORMATION COMMUNICATION TECHNOLOGY

CLASS:  SS 1

DATE:

TERM: 2nd TERM

 
WEEK FOUR

TOPIC: OUTPUT DEVICES

Reference book: Hiit @ School, Computer Studies for Senior Secondary Education.

CONTENT 

An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by a computer to the outside world. 

In computing, input/output, or I/O, refers to the communication between information processing systems (such as a computer). Inputs are the signals or data sent to the system, and outputs are the signals or data sent by the system to the outside world.

Features and uses of Output devices 

The types of output devices are: monitor, printer, speaker, plotter, microphone, scanner, etc.

Monitor

The most frequently used output is the monitor also known as Visual Display Unit (VDU) or Cathode Ray Tube (CRT).  It is similar to ordinary television screen. The monitor is the electronic device used to displaying output (softcopy) generated by the computer. Images are formed on the monitor by individual dots or picture elements called PIXELS. It is capable of producing clear images in different colours. 

Cathode Ray Tubes: The most common type of monitor for office and the home is the Cathode Ray Tube (CRT).

LCD monitors: Liquid Crystal Display (LCD) monitors were developed because of the bulky nature of CRTs.  Unlike the technology used in CRTs, the technology for portable monitors involves liquid crystals.  LCD monitors are thinner than CRTS. LCD (palmtop, laptop, notebook, monitors, etc)

Speaker

A loudspeaker, or speaker, is an electro-mechanical transducer which converts an electrical signal into sound. The term Loudspeaker is used to refer to both the device itself, and a complete system consisting of one or more loudspeaker drivers (as the individual units are often called) in an enclosure. The loudspeaker is the most valuable element in an audio system, and is responsible for marked audible differences between systems. This is an output device that is external to a computer that is used to output sound.

Plotter 

A plotter is a computer printing device for printing vector graphics. In the past, plotters were widely used in applications such as Computer –Aided Design. 

Structure, types and features of Monitors

A computer monitor comprises the display device, circuitry, and an enclosure. The function of a computer monitor basically is to display text and graphics.

Display Device

This is where the text and graphics are displayed.

Circuitry: the circuitry is the entire electronic components located in the monitor. The internal electronic components are not visible. The external electronic components i.e. the ports and wires at the back of the monitor transfers electricity into the internal electronic components. This supplies the monitor power in order to display text and graphics.

Enclosure: these are panels covering the monitor. 

Types of Monitor

The two types of monitors are Monochrome and Coloured monitors.

Monochrome Monitors: display text and graphics in one colour only. Generally, the colours range from gray to blue to blue to white. They were used to display text on traditional monitors e.g. CRT Monitor. Monochrome monitors are of two types, Monochrome Text Monitor which can only display text and number character in single color and Monochrome Graphics Monitor which can display texts as well as graphics such as charts, maps, diagrams and other pictures all in one color.

Coloured Monitors: all modern monitors are nearly colour monitors. They display a myriad of colours of text and graphics. Most Personal Computers today use colour monitors e.g. Liquid Crystal Display (LCD). Different types of colour monitor have been developed.  These are:

1. CGA (Color Graphic Adapter) which can display only 16 colors.
2. EGA (Enhanced Graphic Adapter) which displays 64 colors.
3. VGA (Video Graphic Adapter).  This can display 262,144 colors.
4. SVGA (Super Video Graphic Adapter).  This can display more than 262,144 colors.

EVALUATION

1a. Define an output device.    1b. List FIVE examples of an output device.

2a. State the features and uses of output devices. 

2b. State TWO advantages of LCD monitor over CRT.

READING ASSIGNMENT: HiiT @ School, Computer Studies for Senior Secondary Education. Chapter Six, pages 21-23.

WEEKEND ASSIGNMENT

OBJECTIVES

1. ______ is an output device that shows information. (a) Keyboard   (b) Monitor   (c) CPU
2. Another name for monitor is ____ (a) CPU   (b) VDU   (c) DVU
3. The place where text and graphics are displayed is__. Display Device b) screen c) LCD
4. ______ monitor can display information in different colours.

    (a) Monochrome    (b) Black and White    (c) Colour

5. Images are formed on the monitor by dots elements called___ a) pixel b) LCD c) CRT 

THEORY

1a. Explain the TWO types of monitor. 

1b. Briefly explain the different types of colour monitor.

2a. Write short notes on: Plotter and Speaker.

2b. State the common features and uses of a monitor