Question

implement full subtractor using prom


please help....​

Answer 1

Answer:

Full Subtractor | Definition | Circuit Diagram | Truth Table

Digital Design

Half Subtractor-

Before you go through this article, make sure that you have gone through the previous article on Half Subtractor.

We have discussed-

Half Subtractor is used for the purpose of subtracting two single bit numbers.

Half subtractors have no scope of taking into account “Borrow-in” from the previous circuit.

To overcome this drawback, full subtractor comes into play.

In this article, we will discuss about Full Subtractor.

Full Subtractor-

Full Subtractor is a combinational logic circuit.

It is used for the purpose of subtracting two single bit numbers.

It also takes into consideration borrow of the lower significant stage.

Thus, full subtractor has the ability to perform the subtraction of three bits.

Full subtractor contains 3 inputs and 2 outputs (Difference and Borrow) as shown-

Designing a Full Subtractor-

Full subtractor is designed in the following steps-

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

A B Bin Bout (Borrow) D (Difference)

0 0 0 0 0

0 0 1 1 1

0 1 0 1 1

0 1 1 1 0

1 0 0 0 1

1 0 1 0 0

1 1 0 0 0

1 1 1 1 1

Truth Table

Step-03:

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

Also Read- Full Adder

Step-04:

Draw the logic diagram.

The implementation of full adder using 1 XOR gate, 3 AND gates, 1 NOT gate and 1 OR gate is as shown below-

Answer 2

Explanation:

Step-01: Identify the input and output variables- Input variables = A, B, Bin (either 0 or 1) ...

Step-02: Draw the truth table-

Truth Table.

Step-03: Draw K-maps using the above truth table and determine the simplified Boolean expressions- Also Read- Full Adder.

Step-04: Draw the logic diagram.