Computer Components

A computer is a complex device but having a basic idea of the building blocks can help understand enough to make sensible choices of devices.
The image below is a simplified diagram of the major elements of a computer.
It does NOT show the electrical connections between each part.


The parts and their functions are described below:

Component Function Desk Computer Laptop Tablet Mobile Phone
Processing Computing instructions from apps & user Yes Yes Yes Yes
Working Memory Storing instructions and results Yes Yes Yes Yes
Long Term Storage Storing apps & data Yes Yes Yes Yes
Power Provides power to all parts Yes Yes Yes Yes
Screen or Monitor Displays information to user Yes Yes Yes Yes
Video Stores information for display Yes Yes Yes Yes
Touch Control Monitors input by user Keyboard Keyboard/screen Screen Screen
Position Measures device tilt No Some Yes Yes
Cellular SIM & Connection to mobile network No Some Some Yes
GPS Global Position, location on earth from satellites No No Yes Yes
Bluetooth Local wireless connection to accessories Some Some Yes Yes
WiFi Wireless connection to internet Some Yes Yes Yes
Sound Audio output to speakers or headphones Yes Yes Yes Yes
Wired Cable based connection to other devices (USB cable etc) Yes Yes Yes Yes

The most important parts to consider are:

Size of the Working Memory, measured in Gigabytes, typical sizes shown in the image.

  • Where memory is concerned, more is better.
  • On a desktop or laptop computer this memory is usually referred to RAM (random access memory)

Size of the Long Term Storage, measured in Gigabytes, typical sizes shown in the image.

  • Up to a point, more is better but also consider budget impacts
  • Long Term Storage can be a 'hard drive' or 'flash memory' (no mechanical parts)
  • Hard drives are usually slower but larger and used on desktop computers.
  • Flash memory is usually faster, more expensive and used on laptops, tablets and mobile phones.
  • Desktop computers can use flash memory in Solid State Drives for greater speed at higher cost.

Power of the Processing unit.
Newer is generally faster, but the newest and fastest are also the most costly.
Often a middle of the range processor is adequate in performance for most tasks and is cost-effective.

To use Cellular function, the connection to the mobile phone network is made using a SIM card

  • This is essential in a mobile phone
  • Optional at higher cost in tablets. Using a SIM card for data from the mobile phone network.
  • Some laptops include this as an option for data only (no phone calls)

Images and Video
A desktop computer can plug in a camera
Laptop computers usually have a camera built in above the screen
Tablets and mobile phones usually have a camera at the back and another at the front (for 'selfies')

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