TOPIC 4: INPUT DEVICES

Introduction
Input is any data or program instructions people enter into the memory of a computer. People have a variety of options for entering data or instructions into a computer.


Once input is in memory, the CPU can access it and process the input into output. There are two types of input:
data and instructions. Instructions can be in the form of programs, commands, and user responses.
Input devices send data and instructions to the computers.  There are many input devices but the most common ones are the keyboard and the mouse. 
This module will describe the following input devices.
  •   Keyboard
  •   Mouse
  •   Trackball
  •   Light pen
  •   Touch screen
  •   Modem
  •   Scanner
  •   Microphone
  •   Bar code reader
  •   Digital camera
  •   Video digitiser
  • Magnetic ink character recognition (MICR)
  • Magnetic strips or stripes
Storage devices can be used as input devices.

Comments

Post a Comment

Popular posts from this blog

Pen Input

Image
With pen input , users write, draw, and tap on a flat surface to enter input. The surface may be a monitor, a screen, a special type of paper, or a graphics tablet.  A light pen is handheld input device that can detect the presence of light. To select objects on the screen, a user presses the light pen against the surface of the screen or points the light at the screen and then presses a button on the pen.  A stylus is a small metal or plastic device that looks like a tiny ink pen but uses pressure instead of ink.   Some mobile computers and nearly all mobile devices have touch screens that recognize pen input. Most of these devices include a pressuresensitive digital pen or stylus. Pressure-sensitive digital pens typically provide more functionality than a stylus, featuring electronic erasers and programmable buttons. Computers and mobile devices often use handwriting recognition software that translates the handwritten lett...
Read more

Laptop, Tablets and Palmtop Computers

Image
The second type of computer that you may be familiar with is a laptop computer. Laptops are battery or AC-powered personal computers that can be easily carried and used in a variety of locations be a car, a taxi or airjet.    Example Laptop Computer The primary benefit of a laptop computer is its small size and easy portability . They use special screens, rather than the traditional bulky VDUs (Visual Display Units), which allows for longer battery life as well as portability. A laptop computer is sometimes called a notebook computer because of its size. Notebooks and Palmtop computers A newer term, “Notebooks”, simply indicates a VERY small laptop. These are especially popular with salespersons on the move or people giving presentations. While they tend to still be more expensive than an equivalent Desktop computer, they can now match the power of a Desktop computer. Palmtops are even smaller computers which can literally...
Read more

Measuring Memory

Image
Information is stored in the form of bytes.   A byte is a unit of memory in a computer and this byte represents either a character e.g. B or two digits e.g. 12.   These bytes are formed from bits.   Bits, or Binary Digits, may have one of two values.   These are represented by 0 or 1, true or false, but will actually be the presence or absence of magnetisation. Relationship between Bits, Bytes, Kilobytes, Megabytes and Gigabytes A Bit is the smallest element of data storage.   Bits grouped together form bytes.   With the ASCII code a combination of 8 bits form 1 byte.   For example when you type a letter ‘a’ the computer will understand that as a combination of zeros and ones e.g. 01100001.   The following indicates the relationship between different data units 8 bits = 1 byte 1024 (2 10 ) bytes = 1 Kilobyte 1 048 576 (2 20 ) bytes = 1024 Kilobytes = 1 Megabyte 1 073 741 824 bytes = 1024 Megabytes = 1 G...
Read more