# Binary Number System

. Number system is a way to represent numbers.
. Binary Number system represent numeric values using 0's and 1's.
. Computers stores everything in binary.
. A digit in binary is called 'Binary Digit' or 'Bit'.

### Why do computers use Binary Number System?

. Computers are constructed from billions of ON/OFF switches.
. All working mechanism depends on ON/OFF of switch to read and write.
. Switch ON  -> 1
. Switch OFF -> 0
. Whatever input we send, it is converted into digital signals and passes from component to component.
. In storing devices ( registers), it is converted into binary.
. Flip-flops in registers are used to make storage cells, by ON/OFF technique to store memory.

### Binary Vs Decimal Number System:

. Generally we use decimal number system for indicating numbers in real time.
. It means from 0-9.
. But, computers can understand only binary numbers, so it must be converted.

#### Conversion of Decimal to Binary:

. Any number in decimal is easily converted into binary by using modulo technique:

#### Conversion of Binary to Decimal:

. When the data is sent out, first it should be converted into decimal.
. The technique used in converting binary to decimal is by multiplying each digit with powers of 2 incrementing from left and adding them.

#### Characters to Binary:

. All the characters what we sent to computer, they are encoded into binary.
. ASCII Code is used to convert characters to decimals and then, decimal to binary.
. Suppose, we send letter 'A', then ASCII code for 'A' is 65. 65 is converted into 1000001.