Input Devices and Output Devices | Complete Notes | CBSE Class 11 Informatics Practices (2026–27)
Class 11 · Informatics Practices
Input Devices and Output Devices
A computer communicates with users through input devices and output devices. Input devices help users enter data and instructions into a computer, while output devices present the processed information in a form that users can understand. Together, they play an important role in the Input–Process–Output (IPO) cycle of a computer system.
What are Input Devices?
An input device is a hardware component used to enter data, instructions, or commands into a computer system.
Common Input Devices
| Device | Purpose |
|---|---|
| Keyboard | Typing text, numbers, and commands |
| Mouse | Pointing, selecting, and dragging items |
| Scanner | Converting paper documents into digital form |
| Microphone | Recording voice and audio |
| Webcam | Capturing images and videos |
| Barcode Reader | Reading barcodes on products |
| QR Code Reader | Reading QR codes |
| Touchscreen | Accepting input through touch |
Keyboard
The keyboard is the most commonly used input device. It allows users to enter text, numbers, and commands into the computer.
Types of Keys
- Alphabet Keys
- Numeric Keys
- Function Keys (F1–F12)
- Arrow Keys
- Special Keys (Enter, Shift, Ctrl, Alt, Esc)
Mouse
A mouse is a pointing device used to move the pointer and interact with graphical objects on the screen.
Common Mouse Operations
- Click
- Double Click
- Right Click
- Drag and Drop
- Scroll
Scanner
A scanner converts printed documents or photographs into digital images that can be stored and edited on a computer.
Applications
- Digitizing documents
- Scanning photographs
- Archiving records
Microphone
A microphone captures sound and converts it into digital signals for recording, communication, or voice recognition.
Applications
- Online classes
- Video conferencing
- Voice recording
- Voice assistants
Webcam
A webcam captures images and videos for video calls, online meetings, and recording.
Barcode Reader
A barcode reader scans printed barcodes to retrieve product information quickly and accurately.
Applications
- Retail stores
- Libraries
- Inventory management
QR Code Reader
A QR code reader scans Quick Response (QR) codes to access digital information such as websites, payment links, contact details, or product information.
Touchscreen
A touchscreen functions as both an input and an output device. It displays information and also allows users to interact directly with the screen using touch.
What are Output Devices?
An output device is a hardware component that presents processed information to the user in visual, printed, or audio form.
Common Output Devices
| Device | Purpose |
|---|---|
| Monitor | Displays text, images, and videos |
| Printer | Produces hard copies |
| Speakers | Produces sound output |
| Projector | Displays output on a large screen |
| Plotter | Prints large engineering drawings and maps |
Monitor
A monitor is the primary output device that displays text, graphics, videos, and animations.
Applications
- Online learning
- Programming
- Gaming
- Video editing
Printer
A printer produces permanent paper copies of digital documents.
Types of Printers
- Inkjet Printer
- Laser Printer
Speakers
Speakers convert digital audio signals into sound that users can hear.
Projector
A projector displays computer output on a large screen, making it suitable for classrooms, seminars, and conferences.
Plotter
A plotter is a specialized output device used to produce large, high-precision drawings such as engineering designs, architectural plans, and maps.
Input Devices vs Output Devices
| Input Devices | Output Devices |
|---|---|
| Send data to the computer. | Receive processed information from the computer. |
| Used before processing. | Used after processing. |
| Examples: Keyboard, Mouse | Examples: Monitor, Printer |
Inkjet Printer vs Laser Printer
| Feature | Inkjet Printer | Laser Printer |
|---|---|---|
| Printing Technology | Liquid ink | Toner powder |
| Speed | Moderate | Fast |
| Photo Printing | Excellent | Good |
| Cost per Page | Higher | Lower |
Real-Life Examples
| Situation | Device Used |
|---|---|
| Typing an assignment | Keyboard |
| Joining an online class | Webcam and Microphone |
| Printing a report card | Printer |
| Shopping at a supermarket | Barcode Reader |
| Making a UPI payment | QR Code Reader |
Common Errors
| Mistake | Correct Concept |
|---|---|
| Monitor is an input device. | Monitor is an output device. |
| Printer stores data permanently. | A printer only produces hard copies; it does not store data. |
| Barcode Reader and Scanner perform the same task. | A scanner digitizes documents, while a barcode reader reads barcodes. |
| Touchscreen is only an output device. | A touchscreen functions as both an input and an output device. |
Quick Revision
| Device | Remember |
|---|---|
| Keyboard | Text input |
| Mouse | Pointing device |
| Scanner | Converts paper to digital form |
| Barcode Reader | Reads product barcodes |
| Monitor | Displays output |
| Printer | Produces hard copy |
| Projector | Displays on a large screen |
CBSE Exam Tips
- Differentiate clearly between input devices and output devices.
- Remember that a touchscreen acts as both an input and an output device.
- Know the purpose and applications of commonly used devices.
- Understand the difference between scanner and barcode reader.
- Compare inkjet and laser printers for objective and short-answer questions.
Summary
Input devices enable users to provide data and instructions to a computer, while output devices present the processed results. Devices such as keyboards, mice, scanners, microphones, and webcams help capture input, whereas monitors, printers, speakers, projectors, and plotters display or produce output. Together, these devices enable effective interaction between users and computer systems and are essential components of every modern computing environment.