COMPUTER TECHNOLOGY
Section 1
Computer Basics · Outer Hardware
This section is about the parts of a computer you can see and touch — the case, the things you plug into it, and the difference between the devices that send information in and the ones that bring it back out.
The case and where files go
Slides 2–3
Peripherals and input devices
Slides 4–6
Output devices
Slides 7–10
Devices that do both
Slide 11
The Basics
The box or case of a computer has a power switch and a light or two. It also has ports to plug in devices. This case houses all of the important computer components. If it stands up tall, it is a tower case. If it sits flat, it is a desktop case.
The case does more than hold everything together. It keeps dust out, channels air across the parts that get hot, and gives every port a fixed place to sit.
a tower case with a glass side panel
Tower
Stands upright, usually beside or under a desk. More room inside means easier upgrades and better airflow, so towers run cooler and quieter under load.
Desktop
Lies flat, often with the monitor sitting on top. Saves height on a crowded desk but leaves less room inside for adding parts later.
All-in-one
No separate case at all — the whole computer is built into the back of the monitor. Tidy, but almost nothing inside can be replaced.
Saving Files Somewhere Else
Not every file is stored inside the computer you are using. Some files live on a server in this building, and some live in a data center hundreds of miles away. Either way you reach them over a network rather than from a drive inside the machine in front of you. That is why you can log in to a different computer in the building and still find your work waiting.
a data center — rows of servers holding other people’s files
Network drives
At school your work saves to the H: drive. Those files sit on a school server, so you can sign in to any computer in the building and find them waiting.
Cloud storage
Google Drive, OneDrive and iCloud keep files on a company’s computers and reach them over the internet. The same file opens on a phone, a laptop or a school computer.
The catch
Both need a connection. No network means no H: drive; no internet means no cloud. Files kept only on one machine are lost if that machine fails.
Peripheral Devices
The word peripheral refers to an external or internal device that connects to a computer and adds functionality to a computer. Peripheral devices can either be internal (inside the computer) or external (outside the computer)
Strictly, the computer itself is the processor, the memory and the storage. Almost everything else you can name is a peripheral attached to it.
external peripherals plug into ports like these
Internal
Fitted inside the case, usually into a slot on the motherboard. Graphics cards, sound cards and network cards all count, even though you never see them.
External
Plugs into a port on the outside. Keyboards, mice, monitors, printers and headphones are the ones you handle every day.
Drivers
Every peripheral needs a driver — a small piece of software telling the operating system how to talk to it. Windows installs most of them automatically.
Peripheral Input Devices
There are several ways to get new information or input into a computer. The two most common ways are the keyboard and the mouse.
Pressing the keys on the keyboard tells the computer what to do.
The mouse uses a laser or optical sensor to move the cursor around on the screen. The mouse also has buttons that give the computer directions.
the keyboard
the mouse
Shortcuts
Ctrl+C copies, Ctrl+V pastes, Ctrl+Z undoes, Alt+Tab switches windows. Four keys that will save you more time than anything else on this slide.
Mouse buttons
Left click selects, right click opens a menu of things you can do to whatever you clicked, and the wheel scrolls or zooms.
Other pointers
A trackpad reads your finger directly, a touchscreen turns the display itself into the input, and a stylus gives you precision for drawing.
Other Peripheral Input Devices
Scanners copy a picture or document into the computer. Some copy machines now include a scanner
A flatbed scanner shines a light across the page and records what bounces back. What you get is a picture of the page, not text — a scanned worksheet cannot be edited until software reads it.
Scanning is only one way in besides the keyboard and mouse. Sound, images and movement can all become input.
a flatbed scanner
Scan quality is measured in dpi — dots per inch. 300 dpi is plenty for text; higher settings mostly just make the file bigger.
Microphone
Turns speech into a signal the computer can store. Voice typing has become accurate enough to write with, and every laptop and phone has one built in.
Camera
Captures stills and video going in. A phone camera also doubles as a scanner, a barcode reader and a QR reader without any extra hardware.
Movement and you
A game controller sends direction and button presses. A fingerprint reader or face scanner sends a measurement of your body as the input.
Output Devices
Output devices display information in a way that you can understand.
The most common output device is the monitor. It houses the computer screen. It allows you to 'see' what you and the computer are doing together.
A monitor produces nothing of its own. It only shows what the computer sends it, which is why a blank screen usually means the fault lies somewhere else.
a 34-inch curved monitor — the labels name the three specs below
Resolution
The number of pixels on the screen. 1920 x 1080 is standard; a 4K screen packs in roughly four times as many, so the picture looks sharper.
Size
Measured diagonally, corner to corner, in inches. A 24-inch monitor is the usual desk size; anything much larger belongs further away.
Refresh rate
How many times per second the picture is redrawn. 60Hz is normal, and 120Hz or higher looks noticeably smoother in fast-moving games.
Did you know?
An LCD monitor can be used as a TV as long as it supports HDMI input . Check out this link:
Also, your TV can be used as a monitor. Check out this link:
One cable, both signals
HDMI carries picture and sound together, which is why a single cable is enough to run a TV from a laptop.
Why a TV is a poor monitor
Pixels are spread over a much bigger panel, so text looks coarse up close. TVs also add processing delay that makes a mouse feel sluggish.
Why a monitor is a poor TV
Most have no tuner, no apps and weak speakers. You need a streaming stick or a console plugged into the HDMI port.
Peripheral Output Devices
A printer is another common part of a computer system. It takes what you see on the computer screen and prints it on paper.
There are two main types of printers. The inkjet printer uses inks to print and it can print in either black and white or color. Laser printers run much faster because they image a whole page at once.
a laser printer
What it really costs
Inkjets are sold cheap and the ink is expensive. Toner costs more up front but far less per page, which is why schools and offices buy laser.
Speed
Measured in pages per minute. A home inkjet manages a handful; an office laser will push out thirty or more without pausing.
3D printers
A newer kind of output altogether. Instead of marking paper, it builds a solid object by laying down melted plastic layer by layer.
More Output Devices
Speakers are output devices that allow you to hear sound from your computer. Computer speakers are just like stereo speakers. There are usually two of them and they come in various sizes.
Sound is an output like any other. The computer turns a file into an electrical signal, and the speaker turns that signal into movement in the air that your ears can pick up.
computer speakers
Already built in
Every laptop and most monitors have small speakers inside. Separate ones exist because a bigger cabinet moves more air and produces deeper sound.
Headphones
The same job, kept private. Many include a microphone, which makes the headset an input device at the same time.
Protect your hearing
Damage from loud earbuds builds up over years and never heals. If the person beside you can hear your music, it is already too loud.
Special Input/Output Devices
Some items are both an input and output device. Examples include: webcam, touchscreen monitors, flash drive
webcam
touchscreen monitor
flash drive
Webcam
Captures video and sound going in. Most also have a light that switches on while recording — information coming back out to you.
Touchscreen
The clearest case. One sheet of glass shows you the picture and reads where your finger lands, so it does both jobs at once.
Flash drive
Data travels in when you copy a file onto it and back out when you open that file somewhere else. The port carries traffic both ways.