Open a computer's cabinet and you find a world of parts working together. This chapter takes you inside the computer to meet the main hardware components and the ports you plug things into.
1Hardware, the motherboard & the CPU
Hardware is the physical parts of a computer. We can split it into:
- Internal hardware — inside the cabinet (motherboard, CPU, RAM, power supply).
- External hardware — outside, plugged in (keyboard, mouse, monitor, printer).
The motherboard
The motherboard is the main printed circuit board. Everything connects to it — it lets all the parts talk to each other and carries power and data between them.
The CPU
The CPU (Central Processing Unit) is the brain. It has three parts:
| Part | Job |
|---|---|
| ALU (Arithmetic Logic Unit) | Does calculations & comparisons |
| CU (Control Unit) | Directs and controls all operations |
| Registers | Tiny, very fast storage used while working |
Watch the data flow through the CPU — click Next step:
- Internal hardware is inside the cabinet (motherboard, CPU, RAM); external hardware is plugged in (keyboard, monitor).
- The motherboard is the main circuit board that connects every part.
- The CPU (brain) has the ALU (calculations), CU (control) and registers (fast temporary storage).
2Power supply & expansion cards
The power supply unit (SMPS — Switched Mode Power Supply) converts the high-voltage AC from the wall socket into the low-voltage DC the computer's parts need, safely.
Expansion cards
Expansion cards plug into slots on the motherboard to add features:
| Card | Adds |
|---|---|
| Sound card | Better audio in/out |
| Graphics/Video card | Better display & gaming performance |
| NIC (Network Interface Card) | Connects the computer to a network |
- The SMPS (power supply) converts wall AC to the low-voltage DC the parts need — never open it.
- Expansion cards plug into motherboard slots to add features.
- Sound card (audio), graphics/video card (display), and NIC (network connection).
3Ports & connectors
Ports are the sockets where you plug in external devices. The common ones:
| Port | Connects |
|---|---|
| USB | Most devices — pen drives, mouse, keyboard, phone |
| HDMI | Modern monitors/TVs (video + audio) |
| VGA | Older monitors (video only) |
| Audio ports | Speakers, headphones, microphone |
| Ethernet / RJ45 | A wired network cable |
- Ports are sockets for plugging in devices.
- USB connects most devices; HDMI carries video + audio; VGA is older (video only).
- Audio ports connect speakers/headphones/mic; the Ethernet/RJ45 port takes a network cable.
★ Practical: identify the parts
Looking at a computer (or pictures):
- Name two internal and two external hardware components.
- Point out the CPU part that does calculations.
- Find the USB and HDMI ports and say what each connects.
- Explain why you should never open the SMPS.
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