Computer Chapter 4

Page 1

Resistive touchscreens

The screen has 2 layers

The visitor presses on the top layer

The top layer would connect to the bottom layer

This creates a circuit

Capacitive touchscreens

Electric charge is spread across the screen

Sensors are located around the field

When the finger touches the screen, the electric charge is transferred to the finger and it changes

The coordinates of this touch are determined by the microprocessor

Gloves: Use capacitive gloves

Use a conducting stylus

Infrared touchscreens:

Infrared rays are sent across the screen from the edges

Sensors capture the beam

Infrared rays form a grid across the screen

The ray is broken when a finger touches the screen

Calculation is made where the beam is broken to locate the touch

Page 2

Primary memory: Memory that is directly accessed by the CPU

Example: RAM (Volatile) & ROM (Non-Volatile)

Secondary memory: Storage not directly accessed by the CPU

Example: HDD & SSD (Non- Volatile)

Off-line storage

Non-volatile storage which can be removed from the computer Eg: DVD