Topic 8 Computer Components
Note: This is quite a long topic, with a good number of photographs. To make the download time acceptable, I have broken the topic down into seven sections, otherwise you would probably gone to bed before the file had finished downloading. The sections are:
Topic 8 (this page)
The questions are in order as you work through the topic, but you can do each section in any order you like.
In this topic we are going to look at what happens inside the computer. When you take the computer out of its box, you will find that instead of the box being crammed full of electronics, it is mostly empty space. That is why a laptop is of manageable size. Even so, the PC is a miracle of miniaturisation; the early computers of thirty years ago would have been the size of a building.
Question 1 Why is the power supply separate from the motherboard? ANSWER
The
main circuit board is called the motherboard.
The circuitry is quite complex with lots of chips on it.
Unlike simpler electronic circuits, the motherboard is built up of a
number of different layers. Problems
with the motherboard are usually impossible to fix, and it’s far easy and
cheaper to buy a new motherboard, at a cost of £75 to £100, not vastly
expensive considering what it is.
The RAM (random access memory), usually about 256 megabytes of memory. RAM is very fast, and feeds the CPU with the data it is working on.
The ROM (read only memory) is a chip which is used to get the computer working as soon as it’s turned on. This chip is often called the BIOS (basic input output system), and contains the fundamental data needed for the computer to be able to work.
The CPU (central processing unit), the “brain” of the computer. It is a single large chip with many connectors. It has a heatsink on top, often with a fan, which keeps it cool. If it gets hot, it may go into thermal runaway and be destroyed. There is a temperature detector to prevent this by turning the CPU off before hand.
Expansion ports are provided. These are connectors to various different devices such as a graphics card, a sound card, or a modem.
Question 2 In the picture below, label the components. Two have been done as an example.
Graphics Card
The picture below shows a video graphics card.
The graphics card translates digital signals from the CPU into analogue signals which are further processed by the monitor to give us a picture. The earliest graphics cards did only black and white. 256 colours came in the eighties. Nowadays the standard is 32-bit, which gives 16 million colours. Some can offer 64-bit colour, which gives huge numbers of colours, but not many monitors can achieve this resolution.
Each colour is given an 8-bit code (i.e. eight binary numbers 0 or 1), which gives 28 = 256 combinations. 16 bit colour gives 65 536 combinations.
Question
3 Explain what a sound card does in a computer.
ANSWER
Random access memory is essential for a computer. When you open a program, instructions are copied off the hard disk onto the RAM. All the data you process goes back to RAM until you save it. Unfortunately RAM is volatile, which means that every thing gets lost when you turn off the computer. Here is a card (circuit board) with RAM chips that give 2 megabytes of RAM, pretty primitive.
Question 4. Explain what the risks are of not saving your work regularly. ANSWER
The CPU processes the data by adding
binary numbers. It does
subtractions by a process of complimentary addition.
It multiplies by serial addition and divides by serial complimentary
addition. The moving scenery in a
flight simulator is the result of these additions.
Many other complex things done by computers are the result of these
additions, done up to 2000 million times a second.
Now go on to Computer Architecture