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SSC CGL Preparation – Day 3
Computer Basics: Input / Output Devices
Input and Output (I/O) devices are essential components of a computer system that allow interaction between the user and the machine. Let’s understand them thoroughly:
🖥️ 1. Input Devices
Input devices are hardware components used to enter data and instructions into a computer system.
🔹 Common Input Devices:
| Device | Description |
|---|---|
| Keyboard | Used to input alphanumeric data and commands. |
| Mouse | A pointing device that controls the cursor on the screen. |
| Scanner | Converts physical documents into digital form. |
| Microphone | Captures audio input for voice recognition or recording. |
| Webcam | Captures real-time video input. |
| Joystick/Gamepad | Used mainly for gaming to control characters or cursor movement. |
| Touchscreen | Works both as input and output; accepts touch gestures. |
| Barcode Reader | Scans barcodes printed on products to fetch stored data. |
| Biometric Devices | Capture biometric data like fingerprints, facial features, iris scans, etc. |
📌 Additional Input Devices:
- Light Pen – Detects light and allows drawing on screen.
- Trackball – Similar to a mouse, but the ball is on top.
- Digital Camera – Captures still images and transfers them digitally.
🖨️ 2. Output Devices
Output devices allow the computer to communicate the results of processing to the outside world.
🔹 Common Output Devices:
| Device | Description |
|---|---|
| Monitor (VDU) | Displays visual output, including text, images, and videos. |
| Printer | Produces a hard copy of digital documents or images. |
| Speakers | Output audio like music, alerts, or voice. |
| Headphones | Personal audio output device. |
| Projector | Projects visual display onto a larger surface or screen. |
| Plotter | Used for printing high-precision graphics, like blueprints or maps. |
📌 Types of Monitors:
- CRT (Cathode Ray Tube) – Older, bulky monitors.
- LCD (Liquid Crystal Display) – Thin, flat-panel displays.
- LED (Light Emitting Diode) – More efficient and advanced than LCD.
- OLED – Advanced display with higher contrast and deep blacks.
🔁 3. Input/Output (I/O) Devices
Some devices perform both input and output functions, known as I/O devices.
🔹 Examples:
| Device | Input | Output |
|---|---|---|
| Touchscreen | User touches (input) | Displays output visually |
| Modem | Receives & sends data | Bi-directional data transmission |
| Network Card (NIC) | Sends & receives data over a network | |
| Headset (with mic) | Microphone (input) | Speakers (output) |
🧠 4. Key Differences Between Input and Output Devices
| Input Devices | Output Devices |
|---|---|
| Feed data into the computer | Receive processed data from the computer |
| Cannot display results | Cannot accept new data |
| Examples: Keyboard, Mouse | Examples: Monitor, Printer |
💡 5. Points to Remember
- A scanner is an input device.
- Monitor and printers are output devices.
- Touchscreen is both an input and output device.
- Plotters are used for printing high-quality drawings.
- Joystick is mainly used for gaming applications.
- Biometric sensors are increasingly used for authentication.
