Sunday, December 07, 2014
An input device is any peripheral (piece of computer hardware equipment) used to provide data and control signals to a computer. They are the devices that feed data into a computer.
Examples of input devices include keyboards, mouse, scanners, digital cameras and joysticks.
►The keys include the letter keys (0, 1, 2, ..., 9; A, B, Z), which are generally laid out in the same style as in typewriters are known as Alphanumeric Keys.
►'Caps lock' and 'Num lock' keys are called as Toggle Keys because when pressed, they change their status from one state to another.
►Numeric Keypad is a keypad located on the right hand side of the keyboard. It consists of digits and mathematical operators.
►A Modifier key is a special key (or combination) on a computer keyboard that temporarily modifies the normal action of another key when pressed together. By themselves, modifier keys usually do nothing; that is, pressing any of the Shift, Alt, or Ctrl keys alone does not (generally) trigger any action from the computer.
►A Mouse is the most popular input device which is used today for interactive processing and for the one line entry of data for batch processing.
►Drag and Drop refers to the action of clicking and holding down the mouse button, while moving the mouse and then releasing the mouse button.
The first computer mouse was invented by Douglas Engelbart.
►Joystick is the device that moves in all directions and controls the movement of a pointer.
►A Touch Screen is a type of display screen device that is placed on the computer monitor to allow direct selection or activation of the computer when the user touches the screen.
►Light Pen is the pen shaped device, which can sense light and is used to point at spots on a video screen.
►A technology enables a high-speed reading of large quantities of data and transferring these data to the computer without using a keyboard. It is referred as Optical Mark Reader (OMR).
It uses a beam of light that is reflected on the paper with marks, to capture presence and absence of marks.
►MICR reads the characters by examining their shapes in a matrix form and the information is then passed `on to the computer. MICR stands for Magnetic Ink Character Reader.
It provides a high level of security and is therefore used by the banking industry for faster processing of the cheques
►It is a machine readable code, which is represented by parallel vertical lines with varying widths. For reading these bar-coded data, a device is used, which is known as a Bar Code Reader (BCR)
►Optical Character Recognition (OCR) is used to scan the document containing text.
It is the mechanical or electronic conversion of scanned or photographed images of typewritten or printed text into machine-encoded/computer-readable text.
►A keyboard is a typewriter-style device, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches.
Most of the commonly available personal computers have a keyboard, popularly known as Qwerty.
►The keys labelled Fl to F12 on the keyboard are called Function Keys.
►An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system (such as a computer) which converts the electronically generated information into human-readable form
►The printed form of output is referred as Hard Copy.
The form of output displayed on the screen is referred as Soft Copy.
►The device that prints information from the computer onto the paper is Printer.
Pages Per Minute (PPM) is the unit used to count the speed of the printer.
►On the basis of technology, printers are categorised into Impact and Non- Impact Printers.
►Impact printers create an image by using some mechanism to physically press an inked ribbon against the page, causing the ink to be deposited on the page in the shape desired.
►Non – Impact Printers do not touch the paper when creating an image.
Examples of Non - Impact Printers are Inkjet printers, Laser printers, Solid ink printers, Dye-sublimation, Thermal wax printers, Thermal auto chrome printers.
►A pen based output device, attached to a computer for making vector graphics, that is, images created by a series of many straight lines is known as Plotters.
►The number of pixels displayed on a screen is known as Resolution.
►A Monitor is a TV-like display attached to the computer on which the output can be displayed and viewed. It can either be a monochrome display or a colour display.
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