Design, Construct, and Test of a Half Adder Circuit Using AutoCAD

Experiment No:

Experiment Name: Design, Construct, and Test of a Half Adder Circuit Using AutoCAD

Theory:

A half adder is a digital circuit that performs the addition of two binary digits. It has two inputs, usually denoted as A and B, and two outputs: the sum (S) and the carry (C). The half adder's truth table is as follows:

A B Sum (S) Carry (C)

0 0         0          0

0 1         1          0

1 0         1          0

1 1            0              1

The Boolean equations for the outputs are:

Sum (S) = A XOR B

Carry (C) = A AND B

These logic gates are fundamental components in digital electronics and are used in more complex arithmetic circuits.

Apparatus:

Computer with AutoCAD software

AutoCAD Electrical toolkit (if available)

Digital Logic simulation software (optional for testing)

Basic understanding of logic gates and digital circuits

Circuit Diagram:

Procedure:

Design the Circuit:

Open AutoCAD on the computer.

Using the drawing tools, create symbols for the XOR and AND gates.

Label the inputs A and B.

Draw connections from inputs A and B to the XOR gate to produce the sum output S.

Similarly, draw connections from inputs A and B to the AND gate to produce the carry output C.

Ensure all connections are clear and correctly labeled.

Construct the Circuit:

Using AutoCAD's electrical toolkit, if available, insert predefined symbols for XOR and AND gates.

Connect the gates as per the circuit diagram designed in the previous step.

Verify that all connections are properly made and there are no open circuits.

Test the Circuit:

For physical testing, if the design is intended to be realized on a breadboard, follow these steps:

Gather XOR and AND gate ICs (e.g., 7486 for XOR, 7408 for AND).

Connect the ICs on a breadboard as per the AutoCAD design.

Apply power supply to the ICs.

Provide binary inputs using switches or a function generator.

Observe and record the outputs using LEDs or a logic analyzer 

Discussion:

The half adder circuit designed in AutoCAD successfully demonstrated the principles of binary addition using fundamental logic gates. The XOR gate correctly produced the sum of the two inputs, and the AND gate correctly generated the carry.