A computer has got four main unit i.e. Input Unit, Central Processing Unit and Output Unit and Auxiliary Memory, for make computer usable by users.
The study of digital computer involves the study of two specific branches :
1) COMPUTER HARDWARE
1) COMPUTER HARDWARE
2) COMPUTER SOFTWARE
1) COMPUTER HARDWARE:-
The physical components of a computer system, such as machine parts are known as Computer Hardware. Basically these comprise the CPU, the Input Device and Output Device and various storage devices. Now we will learn about some hardware units of computer.
It is actually a device which provide man to machine communication with computer. Input data may be linguistic, mathematical, Graphical, Audio, Visual and Audio-Visual.
Followings are some popular Input Devices:
- Punch Card
- MICR (Magnetic Ink Character Recognition)
- OMR (Optical Mark Reader)
- OCR (Optical Character Reader)
- Track Ball
- Light Pen
- Voice Input
- Touch Screen
The most common and primary type of input device is the keyboard. Which resembles to the typewriter keyboard. The keys on the computer keyboard serves two types of function, data entry and control operations. Computer keyboard has control keys, special function keys (F1, F2 to F12) separate numeric keypad etc..
MICR is widely used by banks to process the tremendous volume of cheques written each day. The sample cheque is pre - coded along the bottom with the bank identification number and depositors Account number. These special symbols are printed the with a special ink that contains magnetizable particles of iron oxide.
The OMR is a device which can detect the presence or absence of a mark on a paper. The presence of mark is detected due to intensity of light being reflected from the mark. OMR is used in reading answer sheets, questionnaires etc..
OCR is an improvement over OMR. This can not only detect a mark but also recognize it's shape and identify characters directly from source document. The presence of any other mark can confuse the device.
This is one of the most popular types of specialised input device for terminal or micro computer. It is used as a pointing device. A mouse enable the user to manipulate a pointer or an arrow on terminal or micro computer screen.
The scanners are essentially "Optoelectronic" devices which convert any type of printed or written information including photographs into digital pulses which can be manipulated by computer into any mode.
VOICE INPUT / RECOGNITION DEVICE:
It convert human language into machine language. A micro phone or telephone is used to convert human speech into electronic signals.