**Subtractor**: Subtractor is the one which used to subtract two binary number(digit) and provides Difference and Borrow as a output.In digital electronics we have two types of subtractor.

**Half Subtractor****Full Subtractor**

**Half Subtractor**:Half Subtractor is used for subtracting one single bit binary digit from another single bit binary digit.The truth table of Half Subtractor is shown below.

Like Adders Here also we need to calculate the equation of Difference and Borrow for more details please read What is meant by Arithmetic Circuits?

Difference = A'B+AB'=AB

Borrow=A'B

The logic Diagram of Half Subtractor is shown below.

**Full Subtractor :**A logic Circuit Which is used for Subtracting Three Single bit Binary digit is known as Full Subtractor.The Truth Table of Full Subtractor is Shown Below.

From the Truth Table The Difference and Borrow will written as

Difference=A'B'C+A'BB'+AB'C'+ABC

Reduce it like adder

Then We got

Difference=ABC

Borrow=A'B'C+A'BC'+A'BC+ABC

=A'B'C+A'BC'+A'BC+A'BC+A'BC+ABC ----------> A'BC=A'BC+A'BC+A'BC

=A'C(B'+B)+A'B(C'+C)+BC(A'+A)

Borrow=A'C+A'B+BC

The logic diagram of Full Subtractor is Shown below

This was very neat and simple to understand. Thank you!

ReplyDeleteThank you

ReplyDeleteIt Just Awesome!!! :-)

ReplyDeleteIt's very easy to understand

ReplyDeleteIt's very easy to understand

ReplyDeletei cannot understand the substraction part...how it is 0110 it should be 0010....as 12-10 is 2 which is 0010

ReplyDeletei cannot understand the substraction part...how it is 0110 it should be 0010....as 12-10 is 2 which is 0010

ReplyDeleteIts not like u seen it in a different way.

Delete0 - 0 difference is 0 borrow is also 0

0 - 1 1 is greater than 0 so we need a borrow to subtract 1 from 0 if u get the borrow then difference is 1 and borrow is 1.

1 - 0 difference is 1 and borrow is 0

1 - 1 difference is 0 and borrow is also 0 .

don't think as 0011 - 0101.

I think you are clear now.till you are not clear don't hesitate to contact me.

you need 4 full subtractors to perform the operations like 0011 - 0101

Delete