Full Subtractor

Full Subtractor-

 

  • Full Subtractor is a combinational logic circuit that is used for the purpose of subtracting two single bit numbers taking into consideration borrow of the lower significant stage.
  • Thus, Full Subtractor has the ability to perform the subtraction of three bits unlike half subtractor which can subtract only two bits.
  • It contains 3 inputs and 2 outputs (Difference and Borrow).

 

 

Designing a Full Subtractor-

 

Step-01:

 

Identify the input and output variables-

  • Input variables = A , B , Bin (either 0 or 1)
  • Output variables = D , Bout where D = Difference and Bout = Borrow

 

Step-02:

 

Draw the truth table-

Inputs
Outputs
ABBinBout (Borrow)D (Difference)
00000
00111
01011
01110
10001
10100
11000
11111

Truth Table

 

Step-03:

 

Draw the K-maps using the above truth table and determine the simplified Boolean expressions-

 

 

Step-04:

 

Draw the logic diagram-

 

Logic Diagram

 

Here, Full Subtractor has been implemented using 1 XOR gate, 3 AND gates and 1 OR gate.

 

Get more notes and other study material of Digital Electronics.

Watch video lectures by visiting our YouTube channel LearnVidFun.

Summary
Full Subtractor
Article Name
Full Subtractor
Description
Full Subtractor is a combinational logic circuit that is used for the purpose of subtracting two single bit numbers with a borrow of the lower significant stage unlike half subtractor which can subtract only two bits. It contains 3 inputs and 2 outputs (Difference and Borrow).
Author
Publisher Name
Gate Vidyalay
Publisher Logo
Liked this article? Share it with your friends and classmates now-