Keyboard
Application-word processing
It contains keys that allows you to enter data and instructions into the computer. We all know that Many desktop computers have the numeric keyboard that is on the right side of the keyboard. A standard keyboard is known as QWERTY KEYBOARD because of the layout of it's typing area which is similar to that of a type writer.
Advantages- It is faster than a pointing device
Disadvantages - it takes a lot of time to practice in order to type quickly
Mouse
Application- Menu selection
It is the mouse widely used pointing device. A mechanical mouse has a rubber ball on it's under side to detect movement of the mouse. An optical mouse uses a device that emit and sense the light to detect the mouse's movement.A cordless mouse transmits data using wireless technology such as radio waves or infrared lights.
Advantages- A mouse is easy and convenient to use a graphical interface
Disadvantage- It is not easy to input text with a mouse.
Magnetic Reader
Aplication- used by banks
It can read text printed with magnetised ink. It is most used by banks for processing cheques.
Advantage-Difficult to forge. Documents can be read when folded or written on.
Disadvantage- Reads and encoders are very expensive. Can only accept a few different characters set.
Advantage-Difficult to forge. Documents can be read when folded or written on.
Disadvantage- Reads and encoders are very expensive. Can only accept a few different characters set.
Scanner
Application- Converting a hardcopy to a machine readable form
A scanner is a light sensing device that converts printed text and graphics into a digital form that can be further proccesed by the computer.
Two popular types of scanner are:
Flatbed scanner -works like a copy machine exept that t creates a file of the document rather than a paper copy.
Handheld scanner
This can be passed over the image to be scanned. These are ideal for capturing small images such as signatures and logos. These are used for image processing too.Contains OCR
.
Advantages- Using appropriate software you can edit pictures and insert them in the document.
Disadvantage-A scanner is best for two-dimensional objects only.
OCR-Optical character recognition
Works in conjunction with word processirs . It converts an image of text into a text file that can be edited.It uses a scanner to read an image and compares that image with a set of characters patterns that are stored in the computers databases
Advantages-hard copy can be read directly into the pc without re typing. The characters that are converted can be edited later.
Disadvantage-They often do not work well with handwritten characters or those in unusal fonts.
Watch this video :)
the computer's database.
