INPUT UNIT

The purpose of the input units is to get data and instructions from the user and transmit them into computer memory.
transmit them into computer memory.

1. Keyboard
2. Mouse
3. Floppy drive
4. Scanner
5. CD-ROM
6. Web camera

KEYBOARD
There are 5 different types of keys present on the keyboard.

Alphabet keys (A-Z) 26 Nos.

Number keys (0-9) 20 Nos.

Function keys (F1-F12) 12 Nos

Special keys Home, Ctrl,… 42 Nos.

Arrow keys 4 Nos.


Total number of keys in keyboard 104 Nos.



MOUSE
Mouse is an input device.
It has 2 or 3 buttons.
There is a ball or sensor at the bottom of the mouse which controls the movement of the mouse pointer on the screen.
Scanner
A scanner is device that can transfer an image of a photograph or written information to the computer .
OUTPUT UNIT
Get input from the input unit and then give result through the some hardware device that is mean by output unit.
1. Monitor/Screen/Visual Display unit (VDU)
2. Printer
3. Plotters

MONITOR
It is an output device. It displayed result.
Type of monitor
a) Cathode Ray Monitor (CRT)
b) Liquid Crystal Display (LCD)
PRINTER
It is an output device. It give result in printed form.

CENTRAL PROCESSING UNIT (C
+q sPU)
CPU-Central Processing Unit
The CPU is the heart of a computer. All operations are carried out in this unit only.
It is sub-divided into 3 sub-units
It consists of Arithmetic and Logic Unit (ALU) and control unit, (CU) memory unit (MU)
I) CONTROL UNIT (CU)
This unit controls the flow of data from Memory unit and Arithmetic Logical Unit. Transfer the results from memory to the output device
II) ARITHMETIC AND LOGIC UNIT (ALU)
It takes care of all arithmetic and Logical operations.
Arithmetic operations Like, Addition, Subtraction, Multiplication, Division
III) MEMORY UNIT (MU)
It stores all the information that we give to the computer. It is also called as main memory. The stored information in main memory will be lost, to avoid this situation, we can store immediately in secondary memory.
SECONDARY STORAGE (SS)
Secondary storage capacity is more. It is used for storing data for future use. Secondary memories are external devices. A unit provides such type of addition memory is called secondary memory.
The followings are some secondary storage devices.
1) Hard Disk
2) Floppy Disk
3) CD
4) DVD
5) Memory Stick(Pen Drive)