Inputs and Outputs

IGCSE Computer Science 0478 Revision Guide

1. Touchscreens
2. Printers
3. Barcode
4. Monitors
5. Sensors

Touchscreens

Resistive Touchscreens

1. The screens are seperated by the insulating membrane.
2. When it is pressed, the conducting layers make contact and complete the circuit.
3. Position is calculated by a microprocesser

Resistive

Capacitive Touchscreens

1. Indium Tin Oxide ITO coated layers
2. The screen behaves like a capacitor, storing electrical energy
3. can be touched in more than one place at a time

Capacitive

Detecting Touch

1. change in the electric field at that position
2. Coated with ITO and Electrostatic field
3. Grid formed

Detecting Touch

Infra-red

1. Grid liked pattern of LEDs and Photocells
2. infra-red beam is interrupted
3. calculates the coordinates

Infra-red

Surface Acoustic Wave screens

1. ultrasonic sound waves
2. sound wave travel
3. detected by a reduction in the sound wave amplitude

Printers

Inkjet Printer

Printer drivers carry out the print job

Printer buffer Temporary memory

Laser printers

Laser Printer

3D printer

Additive manufaturing — builds up layer by layer
Subtractive manufacturing — where an object is made
by removing material

Monitors

LED : Light Emitting Diode
LCD : liquid crystal display
CCFL : Cold Cathode Fluorescent Lamp
OLED : Organic Light Emitting Diode

Sensors

Good luck on your exam :)

Image courtesy and references of PG online.