Input and Output Devices

• Hardware refers to the physical components of a computer system.
• Input and output devices are essential components of computer systems that allow users to interact with and receive information from the computer. 
• A peripheral machine, also known simply as a peripheral, refers to an external hardware device that is connected to a computer or another digital device to provide additional functionality or input/output capabilities. 
• Modem (modulator-demodulator) : is a hardware device.
  • Modulation is the process of converting digital data into analog signals for transmission
  • Demodulation is the process of converting received analog signals back into digital data.
  • Modem is Required to access the internet through cables.

Internal Parts of Computer	External Parts of Computer
CPU Drive Blu Ray CD ROM DVD Floppy Drive Hard Drive SSD Fan Modem Motherboard Network Card Power Supply Ram	USB Flash drive Mouse Flat Panel  Monitor LCD Gamepad Keyboard Joystick Microphone Printer Projector Scanner Speakers

Input Devices	output Devices
Keyboard Mouse Touchscreen Scanner Microphone Webcam Graphics Tablet Joystick Barcode Scanner Biometric Scanner Light Pen Track ball MICR – Magnetic ink character reader OCR – Optical character reader OMR – Optical Mark reader	Monitor Printer Speaker Headphones Projector Plotter Video Card Sound Card Braille Reader GPS Speech Synthesizer

Input Devices:

Keyboard: A keyboard is one of the most common input devices used to  enter text, commands, and other data into a computer. 

• • Examples include QWERTY keyboards, ergonomic keyboards, and gaming keyboards.
  • It looks like a typewritter.
  • QWERTY keyboards have 104 Keys.

• The QWERTY keyboard was developed by Christopher Sholes, an American newspaper editor and printer. He designed the QWERTY layout for the Sholes and Glidden typewriter, which was the first commercially successful typewriter. 

• This typewriter, also known as the Remington No. 1, was manufactured by E. Remington and Sons and introduced in 1874.

Various keyboard keys and their functions:

• • Alphanumeric Keys: letters of the alphabet (A-Z) and numbers (0-9). 
  • Function Keys (F1-F12): These are a row of 12 keys (F1 to F12) located at the top of the keyboard used as shortcuts to perform specific tasks.

• F1: Help

• • • F2: Rename
    • F3: Search
    • F4: Open 

• F5: Refresh/Reload

• • • F6: In web browsers, pressing F6 highlights the URL in the address bar.

• F7: Spell Check

• • • F8: Multiple Functions 
      • Boot Menu (During Startup)
    • F9: Refresh (In some applications)
      • Send Email in Active Window.
    • F10: Menu Access
    • F11: Full-Screen Mode (In web browsers)
    • F12: Developer Tools

• Save as an option in MS Word.

• • Navigation Keys: used to move the cursor.
    • Arrow Keys: These are four directional keys (up, down, left, and right) used for navigating within documents, spreadsheets, and web pages.
    • Home: Take the cursor to the beginning of a line or document.
    • End: Takes the cursor to the end of a line or document.
    • Page Up/Page Down: Scrolls the screen up or down one page at a time.

• Modifier Keys:

• • Shift: Used to capitalize letters and access uppercase characters on the same key.
  • Ctrl (Control): Often used in combination with other keys as shortcuts for various commands.
  • Alt (Alternate): Used in combination with other keys to access alternate functions or shortcuts.
  • Windows/Command: Opens the Start menu (Windows key) or the Apple menu (Command key) and is used in various operating system shortcuts.
• Special Character Keys: These keys include symbols and special characters, such as !, @, #, $, %, etc. 
  • They are accessed by holding down the Shift key or Alt key in combination with the alphanumeric keys.
    • Shift + 2 = @
    • Alt + 0176 = degree
• Enter/Return: Confirms a selection, starts a new line in text documents, or submits data in forms.
• Backspace: Deletes the character to the left of the cursor or the selected item.
• Delete: Deletes the character to the right of the cursor or the selected item.
• Tab (Tabular/ Tabulator Key): Indents text or moves between fields in forms and dialog boxes.
• Caps Lock: Toggles between uppercase and lowercase letters. When activated, all letters are typed in uppercase until turned off.
• Esc (Escape): Often used to cancel a command or close dialog boxes and close drop down list/ menus.
• Print Screen/SysRq: Captures a screenshot of the current screen, which can be pasted into image-editing software.
• Pause/Break: Used to pause the execution of certain processes and display system information.
• Insert: Toggles between insert and overwrite mode when typing.
• Num Lock: Activates the numeric keypad for numeric input.
• Scroll Lock: Toggles between scrolling and non-scrolling modes in some applications.
• Windows/Command Lock: Locks the Windows key (Windows key) or Command key (Mac) to prevent accidental activation.
• Multimedia Keys: Some keyboards include multimedia keys for controlling audio and video playback, volume adjustment, and launching media applications.

Punctuation Keys
~	Tilde	#	Octothorpe, Number, Pound, sharp, or Hash
`	Acute, Back quote, grave, grave accent, left quote, open quote, or a push
!	Exclamation mark or Bang	£	Pounds Sterling or Pound symbol
@	At or At symbol	€	Euro
%	Percent	$	Dollar sign
^	Caret or Circumflex	&	Ampersand or And
*	Asterisk or star.	[ ]	square brackets
(	Open parenthesis	)	Close parenthesis
–	Hyphen, Minus or Dash	_	Underscore
+	Plus	=	Equals
{	Open Brace	}	Close Brace
[	Open bracket	]	Close bracket
|	Pipe, Or, Vertical bar Backslash or Reverse Solidus	\	Forward slash, Solidus, Virgule, or Whack
:	Colon	;	Semicolon
”	Quote, Quotation mark, or Inverted commas	‘	Apostrophe or Single Quote
<	Less Than or Angle brackets	>	Greater Than or Angle brackets
,	Comma	.	Period, dot or Full Stop
?	Question Mark	/	backslash
“ ”	quotation marks	‘ ’	single quotes
( )	parentheses	{ }	curved brackets

Mouse: A mouse is a pointing device used to move a cursor on the screen and select items. Examples include optical mice and wireless mice.

Touchscreen: Touchscreens allow users to interact with a computer or device by touching the screen directly. Examples include smartphone touchscreens and interactive kiosks.

Scanner: Scanners are used to convert physical documents or images into digital format. Examples include flatbed scanners and document scanners.

• It was built by Russell A Kirsch in 1956.

Microphone: Microphones capture audio input, allowing users to record voice or input voice commands. Examples include USB microphones and built-in laptop microphones.

Webcam: Webcams capture video input, enabling video conferencing and online video recording. Examples include external webcams and built-in laptop webcams.

Graphics Tablet: Graphics tablets are used by artists and designers for precise drawing and sketching. Examples include Wacom tablets and Huion tablets.

• A digitizer, also known as a digitizing tablet, graphics tablet, or digitizer pad, is a computer input device that allows users to create digital representations of hand-drawn or hand-written images and graphics. 
  • It consists of a flat surface (the tablet) and a stylus or digital pen. 
  • The primary function of a digitizer is to convert analog input (pen strokes, pressure, and position) into digital data that can be used by a computer for various purposes. 

Joystick: Joysticks are input devices Like a Lever primarily used in gaming for controlling movements of any object and actions in games in any direction . Examples include joystick controllers for flight simulation games.

• Used For Cursor Control.

Barcode Scanner: Barcode scanners read barcodes on products for inventory management and retail applications. Examples include handheld barcode scanners and fixed-point barcode scanners at store checkout counters.

Biometric Scanner: Biometric scanners use unique physical or behavioral characteristics, such as fingerprints or facial features, for authentication. Examples include fingerprint scanners and facial recognition systems.

MICR – Magnetic ink character reader

• A Magnetic Ink Character Reader (MICR) is a specialized input device used to read and interpret characters printed with magnetic ink. 
• It is primarily used in the banking industry for processing checks and other financial documents for High Accuracy, Readability, Security, Compatibility and Data Validation.

OCR – Optical character reader

• An Optical Character Reader (OCR) is a technology that is used to convert printed or handwritten text into machine-readable text. 

OMR – Optical Mark reader

• An Optical Mark Reader (OMR) is a specialized device or software system that is designed to detect and interpret marks made by a person on a paper or other physical medium, typically in the form of checkboxes or bubble marks. 

Light pen : 

• A light pen is a pointing device and input device that was used with early computer systems. 
• It was a handheld device resembling a pen or stylus, equipped with a light-sensitive photocell or photodiode at its tip. 
• The light pen interacted with a computer’s CRT (cathode-ray tube) monitor to allow users to select objects or input data directly by touching the screen.

Trackball : 

• A trackball is a pointing device used for moving a cursor or controlling the movement of an on-screen object on a computer or other digital display. 
• It consists of a spherical ball housed in a socket that can be rotated in any direction. 
• As the user rolls the ball with their fingers or thumb, sensors inside the trackball detect the ball’s movement and translate it into cursor movement on the screen. 
• Trackballs are particularly useful when space is limited, as they do not require the physical movement of the device itself. 

Output Devices:

Monitor: Monitors display visual output from the computer, including text, images, and videos. Examples include LCD monitors, LED monitors, and gaming monitors.

• • Also known as VDT(Visual Display Terminal) and VDU (Visual Display Unit).
  • VGA stands for Video Graphics Array, and it refers to both a graphics standard and a type of display connector commonly used in personal computers. VGA technology was developed by IBM in 1987 .
    • VGA is used for Displaying Color Graphics.
  • “Soft copy devices” typically refer to devices and technologies that deal with digital or electronic documents, data, and media, as opposed to physical or hard copy formats. Soft copy devices are used to create, display, store, and manipulate digital content. 

• Types of Monitor

• • LCD Monitor
  • LED Monitor
  • OLED Monitor
  • PLASMA Monitor
  • CRT Monitor

LCD Monitor (Liquid Crystal Display):

• LCD monitors use liquid crystals sandwiched between two layers of glass or plastic. When an electric current passes through the crystals, they either block or allow light to pass through, creating images on the screen.
• LCD monitors are used in a wide range of applications, from computer monitors to televisions and smartphones.

LED Monitor (Light-Emitting Diode):

• LED monitors are a specific type of LCD monitor that uses LEDs as a backlight source instead of traditional CCFL (Cold Cathode Fluorescent Lamp) lighting. 
• LEDs provide more even illumination and can be used in thinner displays.
• LED monitors offer improved brightness, contrast, and energy efficiency compared to CCFL-based LCDs. They also tend to be thinner and lighter.
• LED monitors are widely used for computer displays and HDTV screens.

OLED Monitor (Organic Light-Emitting Diode):

• OLED monitors use organic compounds that emit light when an electric current is applied. 
• Each pixel in an OLED display emits its own light, allowing for true black levels and vibrant colors.
• OLED monitors are used in premium smartphones, high-end TVs, and some computer monitors.

Plasma Monitor:

• Plasma displays use small cells filled with ionized gases to produce images. 
• Each cell emits UV light, which excites phosphors to produce colors.
• They were popular for large-screen TVs.

CRT Monitor (Cathode-Ray Tube):

• CRT monitors use electron beams to excite phosphors on a cathode-ray tube to create images. 
• CRT monitors and TVs were once prevalent but have become largely obsolete, replaced by LCD, LED, and other technologies.

Pixel (picture element): 

• A pixel, short for “picture element,” is the smallest unit of a digital image or graphic that can be individually controlled or manipulated. 
• Pixels are the building blocks of digital images and make up the visual elements you see on screens, including computer monitors, smartphones, tablets, and televisions.
• Size and Grid: Pixels are typically square in shape and are arranged in a grid pattern on a display. Each pixel has a specific position in this grid, identified by its horizontal (X) and vertical (Y) coordinates.
• Color and Brightness: Pixels can represent different colors and brightness levels. In a color display, each pixel may consist of multiple color components (e.g., red, green, blue) that combine to create a full spectrum of colors.
• Resolution: The resolution of a display refers to the number of pixels it contains horizontally and vertically. For example, a common Full HD (1920×1080) display has 1,920 pixels in width and 1,080 pixels in height, resulting in a total of over 2 million pixels.

Calculate the total number of colors that a monitor can display

• you need to consider the monitor’s color depth or bit depth, which determines the number of distinct colors it can reproduce.
• Total Colors = 2^Bit Depth

• “Bit Depth” represents the number of bits used for each color channel. 

8-Bit Color  (256 Colors)	Total Colors = 2^8 = 256 colors
16-Bit Color (65,536 Colors)	Total Colors = 2^16 = 65,536 colors
24-Bit Color (16.7 Million Colors, also known as True Color):	Total Colors = 2^24 = 16,777,216 colors
32-Bit Color (16.7 Million Colors with Alpha Channel):	Total Colors = 2^32 = 4,294,967,296 colors

Printer: Printers produce hard copies of documents and images. Examples include inkjet printers, laser printers, and 3D printers.

• • It Accepts the results produced by the computer in a Machine Readable Form.
  • First Printer Developed by Johannes Gutenberg.
  • First Electronic Printer : EP-101 Developed by Epson(Japanese company) in 1968.

• Printer speed is typically measured in pages per minute (PPM) or characters per second (CPS).

Types of Printers

Impact printers	Non-Impact printers
Dot Matrix Daisy Wheel Drum	Inkjet Printers Laser Printer Dye-Sublimation Printers Thermal Printers LED Printers 3D Printers

Printers can be categorized into two main types based on the mechanism they use to create characters and images: impact printers and non-impact printers. 

• The distinction between the two is primarily in the way they physically make contact with the printing surface (typically paper). 

Impact Printers:

• • Impact printers create characters and images by striking an inked ribbon against the paper, causing an impact. 
  • This physical contact with the paper leaves an impression and transfers ink onto the paper. 
  • Impact printers are known for their durability and ability to create carbon copies. 
  • However, they are generally slower and noisier compared to non-impact printers. 
  • Here are common types of impact printers:

• Dot Matrix Printers (Pin Printers)

• Daisy Wheel Printers

Dot Matrix Printers:

• Dot matrix printers use a printhead containing a matrix of tiny pins that strike an inked ribbon to form characters and images through patterns of dots.
• Dot matrix printers are used in applications like invoicing, shipping labels, and forms.

Daisy Wheel Printers:

• Daisy wheel printers use a rotating wheel with character-shaped petals that strike an inked ribbon to create characters on paper.
• Daisy wheel printers were popular for word processing tasks in the past but are now mostly obsolete.

Non-Impact Printers:

• • Non-impact printers create characters and images without any physical contact between the printhead and the paper.
  •  Instead, they use various technologies to deposit ink or toner on the paper, resulting in quieter and faster printing. 
  • Here are common types of non-impact printers:
    • Inkjet Printers

• Laser Printer

• Dye-Sublimation Printers

• Thermal Printers

Inkjet Printer:

• Inkjet printers use tiny ink droplets to create images and text on paper.
• Advantages: They are capable of producing high-quality color and black-and-white prints. They are also relatively affordable.
• Use Cases: Inkjet printers are commonly used for home and office printing, including text documents, photos, and graphics.

Laser Printer:

• Laser printers use a laser beam to create an electrostatic image on a photosensitive drum, which is then transferred and fused onto paper using toner (powdered ink).
• Advantages: Laser printers are known for their fast printing speed, sharp text quality, and lower cost per page for black-and-white prints.
• Use Cases: They are often used in office environments for high-volume printing, including documents, reports, and labels.

Dye-Sublimation Printers:

• Dye-sublimation printers use heat to transfer dye onto a special type of paper or surface, resulting in high-quality, continuous-tone color prints.
• They are commonly used for photography, professional graphics, and sublimation products like Tshirts Printing,  mugs and apparel.

Thermal Printers:

• Thermal printers use heat to create images on specially coated paper or other media. 
• There are two main types: direct thermal and thermal transfer.
• Thermal printers are often used for applications like receipt printing, barcode labels, and shipping labels.

LED Printers:

• LED printers are similar to laser printers but use an array of light-emitting diodes (LEDs) to create the image on the drum.

Some New Printers

Multifunction Printer (MFP) or All-in-One Printer:

• MFPs combine the functionalities of a printer with those of a scanner, copier, and sometimes a fax machine in a single device.

.

3D Printer:

• Technology: 3D printers create three-dimensional objects layer by layer from digital files using materials such as plastic, resin, or metal.
• Advantages: They enable the creation of physical prototypes, custom parts, and complex objects.
• Use Cases: 3D printers are used in various industries, including manufacturing, healthcare, aerospace, and education.

Large Format Printer (Wide-Format Printer):

• Features: Large format printers are designed for printing on oversized paper or other media, often several feet wide.
• Advantages: They are used for creating large-scale posters, banners, architectural drawings, and other oversized graphics.
• Use Cases: Industries like advertising, architecture, engineering, and graphics design rely on large format printers.

Speaker: Speakers output audio generated by the computer, including music, sound effects, and voice. Examples include desktop speakers, Bluetooth speakers, and home theater systems.

Headphones: Headphones provide a private audio output experience, ideal for listening to music or participating in virtual meetings. Examples include over-ear headphones, in-ear earphones, and wireless headphones.

Projector: Projectors display computer-generated images or presentations on a large screen or wall. Examples include multimedia projectors and home theater projectors.

Plotter : A plotter is a computer output device used for printing graphics, diagrams, and technical drawings with a high degree of precision and detail. 

• Unlike standard printers that use raster-based techniques (pixels), plotters use vector-based graphics to create drawings and designs. 
• Plotters are commonly used in engineering, architecture, cartography, and other fields where accuracy and precision are essential. 
• Plotters work with vector graphics, which are defined by mathematical coordinates and equations.
• Used in CAE, CAD, CAM
  • CAM – Computer-Aided Manufacturing:
  • CAE – Computer-Aided Engineering:
  • CAD – Computer-Aided Design:

Braille Display: Braille displays provide tactile output for visually impaired users, converting text and data into Braille characters.

Haptic Feedback Devices: Haptic devices provide tactile feedback to enhance the user experience, such as in gaming controllers that vibrate during gameplay.

LED Indicator Lights: LEDs (Light Emitting Diodes) indicate various system statuses and functions, such as power on/off, Wi-Fi connectivity, and battery status on laptops and smartphones.