Peripheral Devices – SS1 Computer Hardware & GSM Repair Lesson Note (First Term)

A peripheral device is any device that connects to a computer to help it do more.

Behavioural objectives

By the end of the lesson, students should be able to:

1. define a peripheral device and name the three types;
2. describe the printer, the scanner and the projector and state the function of each;
3. distinguish between inkjet and laser printers;
4. explain how to maintain printers, scanners and projectors.

What is a peripheral device?

A peripheral device is any device that connects to the computer from outside to add to what the computer can do.

• Wired connection: the device plugs into a port, which is a socket on the side or back of the computer.
• Wireless connection: the device connects by Bluetooth, with no cable.
• Examples: scanners, printers, projectors and external hard drives.

What are the types of peripheral devices?

There are three types of peripheral devices: input, output and storage.

• Input peripherals: they send information into the computer, as a scanner does.
• Output peripherals: they bring information out to us, as printers and projectors do.
• Storage peripherals: they hold information outside the computer, as an external hard drive does.

What is a printer?

A printer is an output peripheral that puts digital text or images from the computer onto paper.

• Hard copy: the printed version of a document on paper.
• Soft copy: the digital version of a document, kept on the screen or in a file.
• Function: to create physical documents, receipts or photos.

What are the common types of printers?

There are two common types of printer: inkjet and laser.

• Inkjet printer: it sprays liquid ink onto the paper and is good for colourful photos at home.
• Laser printer: it uses a dry powder called toner. It is very fast and is mostly used in offices and schools to print many pages of black-and-white text.

What is the difference between an inkjet and a laser printer?

What is a scanner?

A scanner is an input peripheral that “looks” at a paper document or photo and makes a digital copy of it in the computer.

• Opposite of a printer: a printer puts digital things onto paper, but a scanner brings paper things into the computer.
• Digitising: the process of changing a physical document into a digital file.
• Function: to convert physical documents into digital files, such as PDF or JPEG, so you can email them or save them on your phone.

How does a scanner work?

1. Place the document face down on the glass bed.
2. Close the lid.
3. Start the scan from the computer or from the scanner button.
4. A light slides across the document.
5. A “picture” of the document appears on the monitor.
6. Save the picture as a file, for example PDF or JPEG.

What is a projector?

A projector is an output peripheral that shines the computer image onto a wall or a large white cloth using a bright light and a lens.

• Like a giant monitor: it shows on a large surface what a small screen shows.
• Function: to display computer images on a large surface for many people to see at once.

Why do we use projectors?

• Presentations: a whole classroom of students can see what the teacher is doing.
• Cinema: people can watch movies on a large screen.
• Church and events: song lyrics or notices can be shown to a large crowd.

How do we maintain peripheral devices?

Maintenance is the regular care that keeps peripheral devices working for a long time.

• Cost: peripherals are expensive to replace.
• Main enemies in Nigeria: dust and heat.
• Result of poor care: the devices break quickly.

What are the general maintenance tips?

1. Dusting: use a soft, dry cloth to wipe the printer and the projector lens. Dust can scratch the glass of a scanner or block the cooling fan of a projector.
2. Covering: cover the printer with a cloth or plastic cover when not in use, to keep dust out of the internal rollers.
3. Power protection: use a stabiliser or UPS. Sudden power cuts or “high voltage” can damage the sensitive circuits inside these devices.
4. Regular use: print at least one page every week on an inkjet printer. If it stays unused for months, the liquid ink in the “print head” dries up and blocks it.
5. Proper shutdown: never just pull the plug on a projector. Its lamp gets very hot, so the fan must run for a minute after switching off to cool the lamp.

What care does each device need?

Evaluation

1. If you want to send your birth certificate to a school in another country by email, which device do you need?
2. Why is a “hard copy” different from a “soft copy”?
3. What is the best way to protect your printer from dust in a sandy environment?
4. State two differences between an inkjet printer and a laser printer.
5. Why must you let a projector fan run after switching it off?

Assignment

1. Write a short care guide for a school computer room. Name the three types of peripheral devices with one example of each, and list three ways to look after a projector.