Chapter 2, table of contents

01

02

03

Input devices and their advantages and disadvantages.

Direct data entry devices and their advantages and disadvantages.

Output devices and their advantages and disadvantages.

Input Devices

Keyboard Used to enter text into a computer.

Designed for long-term repetitive use and widely available.

Data cn only be input as fast as it can be typed.

Numeric keypad

Used where numerical information needs to be entered

Simple to use. Limited to numerical data only.

Mouse Used to control the position of the pointer on the screen.

Directly transfer physical movement into the computer system.

Requires a flat surface on which to work.

Touch pad An alternative to a mouse.

Removes the need for a separate mouse.

Requires fine finger control.

Tracker ball An alternative to a mouse

Requires very little space to operate.

The tracker ball is often removable and can be lost.

Remote controls

Devices can be controlled from a short distance.

Device can be difficult to use if remote control is lost.

Held in the hand and used to control TVs, PCs, home entertainment systems.

Scanners Allow hard copies of images or text to be transferred to a computer.

Images can be scanned at very high resolution.

High resolution scanning produces large file size.

Joysticks Used to control objects on a screen in computer games.

Easy to use as there are few buttons.

Limited to directional control.

Steering wheel

Virtual simulators to steer a vehicle.

Just like in a real vehicle.

Limited to driving applications due to limited movement.

Touch screens

Removes the need for a keyboard, allowing a user simply to choose options on screen.

Screen can be cleared easily.

More expensive than a standard display.

Digitl camera

Images resolution very high.

The higher the resolution, the more memory is needed to store it.

Used to take high quality photographs that can be viewed immediately a display.

Microphones Used to input sounds and voices.

Extremely common and inexpensive.

Digital audio files can take up a lot of space.

Temperature Sensor

Used to input temperature readings to a computer.

More accurate than traditional thermometers.

An additional analogue to digital convertor is required to input the signal into a computer to process.

Pressure sensor

Any object of suitable weight can incorrectly activate them.

Light sensor An ADC converter is required.

Used to input pressure readings to a computer.

Able to detect very small changes in light levels.

Used to input light readings to a computer.

More accurate than traditional weighing devices.

Video camera

Sound and video are recorded at the same time.

Takes a lot of computer storage space.

Capture and store moving images.

Webcams Capture still and moving images

Allow people to chat face to face.

Often use lower resolution .

Graphics tablet

Used to input freehand drawings.

Can be used to input much more natural drawings than can be achieved with a mouse.

Requires space and practice to use.

Light pens Used to draw onto a computer display.

Precise inputsRequires practice.

Direct data entry devicesMagnetic stripe readers

Information can be input into a system quickly.

Very limited storage capacity in the stripes.

Used to read data from magnetic stripes on identity and banking cards.

Chip readers More secure than magnetic stripe systems.

Not as widely available as magnetic stripe readers.

Used to read data from chips on bank cards.

PIN pads PIN codes help to prevent unauthorized access.

People can be seen entering the PIN code.

Used to enter data into ATM machines.

RFID reader PIN codes help to prevent unauthorized access.

People can be seen entering the PIN code.

Used to enter data into ATM machines.

Magnetic Ink Character reader

Information can be read very quickly.

Expensive.Used to enter data from bank cheques.

Direct data entry devicesOptical mark reader OMR

Whole page of information can be read quickly.

Incorrect completed forms can result in error.

Used to read and input information from a form or test paper.

Optical Character Reader OCR

Much quicker than manually retyping information.

Handwriting must be neat and legible.

Used to transfer handwritten into text.

Barcode reader

Barcode can become easily damaged and unreadable.

Used to scan identification codes.

Much quicker than manually retyping information.

Output devices and their advantages and disadvantages

Cathode Ray Tube CRT Monitor

Bright, clear display Large and heavyPresent text and graphics..

Thin Film Transistor TFT/LCD Monitor

Lighter and thinner. Can be damaged easily.Used in home and office nowadays.

In Plane Switching IPS/LCD monitor

Expensive.IPS is a screen technology used in modern LCD monitors, mobile phones, and tablets.

Color reproduction is much more consistent.

Light Emitting Diode LED monitor

Lower energy consumption.

Newer technology can be more expensive.

Uses light emitting diodes.

Touch ScreenDisplays can be blocked by fingers using the screen.

Interaction can be instantly seen on the screen.

Multimedia projector

Requires a darkened room.

Can be connected to a computer.

Portable

Can serve as an input and output device.

Laser printer High quality expensive.To print text, graphics, and photos quickly and with high quality.

Inkjet printerSlower than laser printer.Printer and cartridges

are cheap.

Dot matrix printer

Noisy and slow to print.Uses printer head and ribbon to generate characters.

Running cost very low.

To print text, graphics, and photos quickly and with high quality.