Input Devices

Input devices are used by the computer user to input data to the computer. These devices take instructions as input from a user and further transfer to the CPU for processing.

Keyboard	Keyboard – This is the standard input device attached to all computers. The layout of the keyboard is just like the traditional typewriter of the type QWERTY. It also contains some extra command keys and function keys. It contains a total of 101 to 104 keys The keys layout on the keyboard as follow:- Alphanumeric Keys Numeric keys Functional keys Arrow keys Special keys
Mouse	Mouse – A mouse is a pointing device that functions by detecting two- dimensional motion relative to its supporting surface. Physically, a mouse consists of an object held under one of the user's hands, with one or more buttons. The mouse's motion typically translates into the motion of a pointer on a display, which allows for fine control of a graphical user interface Clicking, Double click, and Drag
Trackball	Trackball – The trackball is a variant to the mouse that is used at places where there is no space to move around the mouse. Before the invention of touchpads, the trackballs were used with computer-controlled machines and in special applications like CAD and graphic designing.
Joy Stick	Joystick – It is also a paddle. It is also a pointing device. It consists of a small, vertical lever mounted on a base that is used to steer the screen cursor around. Some joysticks are mounted on a base that is used to steer the screen cursor around. The joystick can be moved left or right, forward or backward, springs are often used to return the joystick to its home center position.
Light pen	Light Pen- A light pen is a pointing device used especially for graphic works. These were developed early in the history of interactive computer graphics. It detects light pulses, rather than emitting light as its name implies. Light pens are sensitive to the short burst of light emitted from the phosphor coating at the instant the electron beam strikes a particular point.
Touch Screen	Touch Screen – A touch screen is an intuitive computer input device that works by simply touching the display screen, either by a finger or with a stylus, rather than typing on a keyboard or pointing with a mouse.
Touchpad	Touchpad- The touchpad is also one of the most popular input devices used in laptops. They are used as a substitute for the mouse. To use moves finger on it and the cursor on the screen moves correspondingly. The touchpads work like touch screens to detect the position of the finger. They are specifically designed to feel the finger, don't use a pencil or pen. Dragging the finger on a touchpad will move the cursor.
Digital Camara	Digital Camera- A digital camera can be used to take pictures. It can be hooked up to a computer to transfer the pictures from the camera to the computer. Some digital cameras hold some internal memory for storage.
MICR OCR	Scanner- The scanner is an input device that uses the paper document as an input. The input data to be scanned maybe a picture or text. The scanner can be categories as  A. Hand-Held Scanner     B. Flatbed Scanner Optical Character Recognition (OCR) - OCR, is the mechanical or electronic translation of scanned images of handwritten, typewritten or printed text into machine-encoded text.  Magnetic Ink Character Recognition (MICR)- This is widely used by banks to process large volumes of Cheques are put inside the MICR. Optical Mark Reader (OMR)- These OMR sheets are directly fed to a computer for grading or evaluation. OMR  answer sheets mostly used in objective type question answers.