Input and Output Devices Notes for SSC Exams
Rahul Kumar
SSC Exam Expert & Content Editor
In this note
- 1.What Are Input and Output Devices?
- 2.Important Input Devices
- 3.Important Output Devices
- 4.Types of Printers
- 5.Monitor Facts
- 6.Keyboard in Detail
- 7.Pointing and Special Input Devices
- 8.Data Entry and Recognition Devices
- 9.Types of Monitors
- 10.Printers in More Detail
- 11.Input, Output and Both
- 12.Important Questions Explained
- 13.Quick Tips to Remember
- 14.Common Mistakes to Avoid
- 15.Quick Revision Points
- 16.Practice Questions With Answers
- 17.More Practice Questions With Answers
- 18.How to Practise This Chapter
- 19.Related Notes and Practice Papers
- 20.Explore More SSC Subjects
- 21.Frequently Asked Questions
PDF Notes: Input and Output Devices Notes for SSC Exams
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Input and output devices are a favourite topic in SSC Computer Knowledge, and the questions usually ask which device is used for which job. These input and output devices notes for SSC list all important devices with their use, followed by practice questions. You can read the Computer Shortcut Keys note for keyboard shortcuts and the Computer Memory Notes note for storage.
What Are Input and Output Devices?
- An input device sends data and instructions to the computer. Example: keyboard, mouse.
- An output device shows the result from the computer to the user. Example: monitor, printer.
- Some devices work as both input and output devices, such as a touch screen, a modem and a headset.
Important Input Devices
| Device | Use |
|---|---|
| Keyboard | Typing text and commands; QWERTY layout, 104 keys on a standard keyboard |
| Mouse | Pointing and clicking on the screen; invented by Douglas Engelbart |
| Scanner | Converts a paper document or photo into a digital form |
| Light pen | Drawing and selecting on the screen |
| Joystick | Playing games and controlling movement |
| Trackball | A fixed ball that is rolled to move the pointer |
| Touchpad | Pointing device on a laptop |
| Microphone | Voice input |
| Webcam | Video input |
| Barcode reader | Reads barcodes on products at shops |
| OMR (Optical Mark Reader) | Reads marked bubbles on answer sheets |
| OCR (Optical Character Recognition) | Converts printed or handwritten text into editable text |
| MICR (Magnetic Ink Character Recognition) | Reads the magnetic ink characters on bank cheques |
| Biometric devices | Fingerprint or iris scanning for identity |
Important Output Devices
| Device | Use |
|---|---|
| Monitor (VDU) | Displays text, pictures and videos; types are CRT, LCD, LED and OLED |
| Printer | Prints the result on paper |
| Plotter | Prints large drawings and maps, used with CAD |
| Speaker and headphones | Sound output |
| Projector | Shows the screen on a large wall or screen |
Types of Printers
| Type | Examples | Feature |
|---|---|---|
| Impact printers | Dot matrix, daisy wheel, line printer | Strike the paper; noisy; can print carbon copies |
| Non-impact printers | Inkjet, laser, thermal | Do not strike the paper; quiet and fast |
Laser printers give the best quality at high speed. Dot matrix printers are still used for multi-copy bills. The speed of printers is measured in CPS or CPM for impact printers and PPM for laser printers, and the quality in DPI (dots per inch).
Monitor Facts
- The smallest unit on the screen is a pixel (picture element).
- Monitor size is measured diagonally in inches.
- Resolution is the number of pixels, such as 1920 x 1080.
- Refresh rate is measured in hertz (Hz).
Keyboard in Detail
- The standard layout is QWERTY, named after the first six letters in the top row. It was designed by Christopher Latham Sholes (typewriter, 1870s).
- A standard keyboard has 101 or 104 keys (the 104-key keyboard includes the Windows keys). Laptops have fewer keys.
- Key groups: alphanumeric keys, function keys (F1 to F12), numeric keypad, navigation (arrow) keys and special keys such as Ctrl, Alt, Shift, Caps Lock, Tab, Esc, Enter and Backspace.
- Toggle keys (Caps Lock, Num Lock, Scroll Lock) work as on and off switches.
- Home row keys are A, S, D, F and J, K, L, ; where the fingers rest while typing.
- The Dvorak layout is another layout designed for faster typing.
Pointing and Special Input Devices
| Device | Details |
|---|---|
| Optical mouse | Uses light (LED or laser) to sense movement; replaced the ball mouse |
| Trackball | Like an upside-down mouse; the ball is rolled by the thumb |
| Touchpad | A flat touch-sensitive pad on laptops |
| Joystick | Moves in all directions; used in games and aircraft simulation |
| Light pen | A pen-shaped device that touches the screen to draw |
| Graphics tablet (digitiser) | A flat board with a stylus used by artists and designers |
| Touch screen | Responds to the touch of a finger; used in ATMs, kiosks and phones |
| Stylus | A pen used on a touch screen |
| Remote control | Wireless input using infrared |
| Gamepad | Handheld game controller |
Data Entry and Recognition Devices
| Device | What it reads | Where it is used |
|---|---|---|
| OMR | Marks on a paper, such as shaded bubbles | Objective exam answer sheets and surveys |
| OCR | Printed or typed text and converts it into editable text | Digitising books and documents |
| ICR (Intelligent Character Recognition) | Handwritten text | Forms |
| MICR | Magnetic ink characters | Bank cheques |
| Barcode reader | Bars of different widths | Shops, libraries, luggage |
| QR code scanner | A square two-dimensional code | Digital payments, tickets |
| RFID reader | Radio waves from a tag | Toll tags, library books, ID cards |
| Biometric scanner | Fingerprint, iris, face | Attendance and security |
| Magnetic stripe reader | Stripe on a card | ATM and swipe cards |
Types of Monitors
| Type | Features |
|---|---|
| CRT (Cathode Ray Tube) | Old, heavy and bulky monitor; uses an electron gun |
| LCD (Liquid Crystal Display) | Thin and light; uses liquid crystals and a backlight |
| LED | An LCD with LED backlight; brighter and uses less power |
| OLED (Organic LED) | Each pixel makes its own light; thin, with deep blacks |
| Plasma | Used in large old TVs |
| Touch screen | An input and an output device |
- Resolution is the number of pixels, such as 1920 x 1080 (Full HD) and 3840 x 2160 (4K).
- Aspect ratio is the ratio of width to height, such as 16:9.
- Refresh rate is how many times the screen is redrawn in a second (60 Hz, 120 Hz).
- Dot pitch is the distance between two pixels; a smaller dot pitch gives a sharper image.
- Monitor colours are made with RGB (red, green and blue), and printers use CMYK (cyan, magenta, yellow and black).
Printers in More Detail
| Printer | Type | Features |
|---|---|---|
| Dot matrix | Impact | Prints with pins hitting an inked ribbon; can print multiple copies; speed in CPS (characters per second) |
| Daisy wheel | Impact | Prints fully formed characters like a typewriter |
| Line printer | Impact | Prints a full line at a time; speed in LPM (lines per minute) |
| Inkjet | Non-impact | Sprays tiny drops of liquid ink; good for colour photos |
| Laser | Non-impact | Uses a laser and toner powder, like a photocopier; fast with high quality; speed in PPM (pages per minute) |
| Thermal | Non-impact | Uses heat on special paper; used for receipts and bills |
| 3D printer | Non-impact | Builds a solid object layer by layer |
Input, Output and Both
| Category | Examples |
|---|---|
| Input only | Keyboard, mouse, scanner, microphone, webcam, joystick, light pen, barcode reader |
| Output only | Monitor, printer, plotter, speaker, headphones, projector |
| Both input and output | Touch screen, modem, headset, network card, external hard disk, pen drive, multifunction printer |
Important Questions Explained
Question 1: Which device is used to read answer sheets with marked bubbles?
Answer: OMR (Optical Mark Reader).
Question 2: Which device reads the characters printed on bank cheques?
Answer: MICR (Magnetic Ink Character Recognition).
Question 3: Which device converts a paper document into digital form?
Answer: A scanner.
Question 4: Which printer is an impact printer?
Answer: A dot matrix printer. Inkjet and laser printers are non-impact.
Question 5: What is the smallest unit of a computer screen called?
Answer: A pixel.
Question 6: Which device is both an input and an output device?
Answer: A touch screen (also a modem).
Quick Tips to Remember
- Learn the full forms of OMR, OCR and MICR as they appear often.
- Remember "keyboard and mouse = input, monitor and printer = output".
- For printers, learn that dot matrix is impact and laser and inkjet are non-impact.
- Link plotter with engineering drawings and CAD.
- Remember the touch screen as a device that does both input and output.
Common Mistakes to Avoid
- Confusing OMR (marks), OCR (text) and MICR (cheques).
- Writing a monitor as an input device.
- Calling an inkjet printer an impact printer.
- Forgetting that a scanner is an input device.
- Mixing the speed units of printers.
Quick Revision Points
- Input: keyboard, mouse, scanner, microphone, webcam, OMR, OCR, MICR.
- Output: monitor, printer, plotter, speaker, projector.
- Impact printers: dot matrix, daisy wheel, line. Non-impact: inkjet, laser, thermal.
- Pixel is the smallest unit on the screen.
- Touch screen is an input and output device.
Practice Questions With Answers
- Which is an input device?
Answer: Mouse (Others are output). - Which device reads bank cheques?
Answer: MICR (Magnetic ink). - Which device is used to check OMR sheets?
Answer: OMR reader (Optical Mark Reader). - Which printer is an impact printer?
Answer: Dot matrix printer (Strikes the paper). - Which device prints large drawings?
Answer: Plotter (Used with CAD). - What does OCR convert images of text into?
Answer: Editable text (Optical Character Recognition). - Which is an output device?
Answer: Monitor (Shows the result). - The smallest dot on the screen is called?
Answer: Pixel (Picture element). - Who invented the mouse?
Answer: Douglas Engelbart (In 1964). - Which device is used to read barcodes in shops?
Answer: Barcode reader (Input device).
More Practice Questions With Answers
- Which keyboard layout is the most common?
Answer: QWERTY (Sholes). - Which monitor technology makes light in every pixel?
Answer: OLED (Organic LED). - Which colour model do printers use?
Answer: CMYK (Cyan, magenta, yellow, black). - Which colour model do monitors use?
Answer: RGB (Red, green, blue). - What is the speed of a laser printer measured in?
Answer: PPM (pages per minute) (Non-impact). - Which device reads RFID tags?
Answer: RFID reader (Radio waves). - Which printer is used to print receipts using heat?
Answer: Thermal printer (Non-impact). - Which key is a toggle key?
Answer: Caps Lock (Num Lock too). - What is 1920 x 1080 called?
Answer: Full HD resolution (Pixels). - Which printer can print multiple carbon copies?
Answer: Dot matrix printer (Impact). - What type of device is a pen drive?
Answer: Both input and output (storage) (USB device). - Which device scans a QR code?
Answer: QR code scanner (Camera based).
How to Practise This Chapter
- Read the tables once and learn the key facts by heart.
- Revise the quick revision points the next day.
- Attempt the practice questions above without looking at the answers.
- Solve a full SSC CGL Tier 1 mini mock to test your general awareness.
- Check the previous year papers to see how SSC asks computer questions.
Related Notes and Practice Papers
- Types of Computers Notes
- Computer Memory Notes
- Computer Shortcut Keys
- Computer Knowledge Notes for SSC
- SSC CGL Tier 1 Mini Mock
Explore More SSC Subjects
SSC exams test many subjects, so connect this topic with the related subjects below:
- General Science Notes
- General Awareness Notes
- Quantitative Aptitude Notes
- Reasoning Notes
- Electrical Engineering (SSC JE) Notes
- All SSC subjects and notes
Frequently Asked Questions
What is an input device?
An input device sends data and instructions to the computer, such as a keyboard or a mouse.
What is an output device?
An output device shows the result of processing to the user, such as a monitor or a printer.
What is the difference between OMR, OCR and MICR?
OMR reads marked bubbles, OCR reads printed text and MICR reads magnetic ink characters on cheques.
What are impact printers?
Impact printers strike the paper to print, such as dot matrix and daisy wheel printers.
Which printer gives the best quality?
The laser printer gives high-quality and fast printing.
What is a pixel?
A pixel is the smallest unit of a picture shown on the screen.
Which devices work as both input and output?
A touch screen, a modem and a headset work as both.
What is a plotter used for?
A plotter prints large drawings, maps and engineering designs.
How many questions come from this topic in SSC exams?
One or two questions usually come from input and output devices.
What is the difference between CMYK and RGB?
RGB is used by screens to make colours with light, while CMYK is used by printers to make colours with ink.
What does PPM measure?
PPM means pages per minute and is the speed of laser printers.
What is a touch screen?
A touch screen is a device that works as both an input and an output device because it shows the display and takes the touch input.
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Types of Computers Notes for SSC Exams
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Computer Memory Notes for SSC Exams: RAM, ROM and Cache
Rahul Kumar
SSC Exam Expert & Content Editor
Rahul is a senior SSC exam strategist with 8+ years of experience helping aspirants crack CGL, CHSL and MTS exams. He writes in-depth notification breakdowns, exam pattern guides and preparation strategies.