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Hardware, Memory & Number Systems

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high importance7 formulas⚡ 14 shortcuts6 subtopics
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Input and output devices

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⏱ 4 min read🧩 5 question types🎯 17 practice Q
The idea in one minute

An input device sends data or commands into the computer. An output device brings results out. Some devices, such as a touch screen, do both. Exams ask you to sort devices, match each device to its job, and tell impact printers from non-impact printers.

01

Input devices

An input device feeds data or commands into the computer.

GroupDevices
Typing and pointingKeyboard, mouse, trackball, touchpad, joystick, light pen, stylus
CaptureScanner, digital camera, webcam, microphone
ReadersBarcode or QR reader, OMR, OCR, MICR, biometric scanner

Tip: OMR reads marks (pencil bubbles). OCR reads characters (printed text). MICR reads magnetic ink on cheques.

02

Output devices

An output device brings results out of the computer.

DeviceWhat it gives
MonitorSoft copy: you can see it but not touch it
PrinterHard copy: output on paper
Speaker, headphonesSound
PlotterHard copy of large drawings and maps
ProjectorA big soft copy on a screen

A 3D printer builds a solid object layer by layer. It is also an output device.

03

Impact and non-impact printers

An impact printer physically strikes the paper through a ribbon. A non-impact printer does not hit the paper.

TypeHow it worksExamples
ImpactStrikes the paperDot matrix, daisy wheel
Non-impactSprays ink, fuses toner or heats paperLaser, inkjet, thermal

Impact printers are noisy and cheap. They can print multi-copy forms. Laser printers use toner and are fast. Inkjet printers use liquid ink.

Rule: If the printer hits the paper, it is impact. Dot matrix is the standard example.

04

Devices that do both

A touch screen takes your finger as input and shows output. A headset has a microphone (input) and speakers (output).

Watch: Touch screen is the standard answer to "both input and output". It is also the trap inside output-only lists.

05

Pointing devices

  • Mouse: the standard pointing device. A ball or an optical sensor tracks movement.
  • Trackball: an upside-down mouse. You roll the ball and the device stays still.
  • Touchpad: the flat mouse replacement on a laptop.
  • Joystick: direction control for games and flight simulators.
  • Light pen and stylus: draw or point directly on the screen.

Every pointing device sends position data in. So all of them are input devices.

06

Device and use pairs

DeviceClassic use
Barcode readerSupermarket billing
OMRChecking pencil-bubble answer sheets
MICRReading the code line on bank cheques
OCRTurning a scanned page into editable text
Biometric scannerAttendance, Aadhaar-style identity checks
PlotterEngineering drawings, maps, posters
Webcam and microphoneVideo calls
07

Question types you will see

Each type: how to recognise it, the method step by step, and one question to try.

Type 1very common4 practice Q

Input device identification

How to spot it:

'Which is an input device' or a list with one device that sends data in.

Method

  1. Ask: does data flow into the computer or out of it?

  2. Scanner, microphone and camera are input devices.

  3. Monitor, printer, speaker, plotter and projector are output devices.

  4. Pick the option that feeds data in.

Why it works:

The direction of data flow decides the class.

Try this

Which of the following is an input device? Monitor, Scanner, Plotter, Speaker

Show solution

  1. Monitor, plotter and speaker all send data out.

  2. A scanner brings a paper document in as an image.

Answer

Scanner

Type 2very common3 practice Q

Output devices, soft copy and hard copy

How to spot it:

'Soft copy', 'hard copy', 'printout' or 'displayed on screen'.

Method

  1. Soft copy is on a screen: monitor, projector.

  2. Hard copy is on paper: printer, plotter.

  3. Speaker and headphones give sound output.

  4. Watch for the touch screen trap.

Why it works:

Hard copy is permanent and touchable. Soft copy is not.

Try this

Output shown on paper is called a...

Show solution

  1. Paper output can be touched and kept.

  2. That is a hard copy.

Answer

Hard copy

Type 3common3 practice Q

Both input and output, odd one out

How to spot it:

'Both input and output' or 'which is NOT an input device'.

Method

  1. Classify every option as input, output or both.

  2. Both: touch screen, headset.

  3. For 'not an input', look for a printer, monitor or speaker.

  4. Use the table, not guesswork.

Why it works:

A device that takes and gives data is both.

Try this

Which device acts as both an input and an output device?

Show solution

  1. Your touch is input.

  2. The display is output.

Answer

Touch screen

Type 4common4 practice Q

Printer types and reader classification

How to spot it:

'Impact printer', 'non-impact', 'plotter' or 'OMR, OCR, MICR'.

Method

  1. Impact means a physical strike: dot matrix, daisy wheel.

  2. Non-impact: laser, inkjet, thermal.

  3. Readers: OMR marks, OCR characters, MICR magnetic ink.

  4. Plotter draws large drawings. A 3D printer builds objects.

Why it works:

Each printer type is defined by how it puts marks on paper.

Try this

Which of the following is an impact printer?

Show solution

  1. Dot matrix pins strike the ribbon against the paper.

  2. Laser, inkjet and thermal never hit the paper.

Answer

Dot matrix

Type 5common

Device and use matching

How to spot it:

'Used for', 'used in a supermarket', 'answer sheets' or 'cheque'.

Method

  1. Underline the job in the question.

  2. Find the device with that job in the pairs table.

  3. Barcode is billing. OMR is answer sheets. MICR is cheques.

  4. Biometric is identity. Plotter is large drawings.

Why it works:

Each device has one classic job in exams.

Try this

Which device is used to check pencil-bubble answer sheets?

Show solution

  1. Pencil bubbles are marks.

  2. The reader for marks is OMR.

Answer

OMR

08

Shortcuts that save time

⚡ Marks, Characters, Ink

OMR is Marks (bubbles). OCR is Characters (text). MICR is Ink on cheques (banks). Match the noun in the question.

Example

Which reader is used for bank cheques?

Show solution

  1. Cheques carry magnetic ink characters.

  2. That is MICR.

Answer

MICR

⚡ Impact means hit

If a printer physically hits the paper (dot matrix, daisy wheel), it is impact. It is noisy but can make copies. Inkjet, laser and thermal never strike the paper.

Example

Which is a non-impact printer: dot matrix or laser?

Show solution

  1. Dot matrix pins strike the ribbon.

  2. A laser fuses toner without hitting.

Answer

Laser

09

Mistakes to avoid

Where most students lose marks on this subtopic.

Mistake 01

Calling a scanner or microphone an output device.

Scanner, camera and microphone send data in. They are input devices.

Mistake 02

Choosing 'touch screen' as output only.

A touch screen is both input and output.

Mistake 03

Mixing up OMR, OCR and MICR.

OMR is marks, OCR is characters, MICR is magnetic ink on cheques.

Mistake 04

Calling a laser printer an impact printer.

Laser, inkjet and thermal printers are non-impact.

Mistake 05

Calling a monitor's display a hard copy.

Monitor output is soft copy. Paper output is hard copy.

10

Quick revision

Read this the night before the exam.

  • Input: keyboard, mouse, scanner, microphone, camera, barcode, OMR, OCR, MICR, biometrics.

  • OMR is marks. OCR is characters. MICR is magnetic ink (cheques).

  • Output: monitor (soft copy), printer and plotter (hard copy), speaker, projector.

  • Impact printers hit the paper (dot matrix). Non-impact are laser, inkjet and thermal.

  • Touch screen is both input and output. A 3D printer makes solid objects.

11

Practice: 17 questions

Sets of 10, mixed across the question types above. Every answer has a step-by-step explanation.

Topic test · 10 questions

Suggested time 4 min · wrong answers go to your mistake notebook automatically.

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