3 – Arithmetic Circuits

Easy Level Questions (10 Questions)

1.     Define a combinational circuit. List two key characteristics that distinguish it from sequential circuits. (5 Marks)

2.     What is the primary function of a Half-Adder circuit? List its inputs and outputs. (5 Marks)

3.     Draw the standard logic symbol for a Half-Adder. (5 Marks)

4.     Explain the purpose of a Full-Adder circuit. How does it differ from a Half-Adder in terms of inputs? (5 Marks)

5.     Draw the standard logic symbol for a Full-Adder. (5 Marks)

6.     Construct the truth table for a Half-Adder, clearly showing its inputs (A, B) and outputs. (5 Marks)

7.     What is a Half-Subtractor? List its inputs and outputs. (5 Marks)

8.     Draw the standard logic symbol for a Half-Subtractor. (5 Marks)

9.     Explain the need for a "borrow-out" in subtraction circuits. (5 Marks)

10.                        Briefly describe what "implementing combinational logic" means in the context of digital circuits. (5 Marks)

Moderate Level Questions (7 Questions)

11.                        Construct the truth table for a Full-Adder. From the truth table, derive the Boolean expressions for both the Sum and Carry-out outputs. (5 Marks)

12.                        Draw the logic circuit diagram for a Half-Adder using basic AND, OR, and NOT gates. Label all inputs and outputs clearly. (5 Marks)

13.                        Implement a Full-Adder circuit using two Half-Adders and one OR gate. Draw the complete logic circuit diagram. (5 Marks)

14.                        Construct the truth table for a Half-Subtractor, clearly showing its inputs and outputs. From the truth table, derive the Boolean expressions for both outputs. (5 Marks)

15.                        Explain how a Full-Subtractor is typically constructed from basic logic gates or using Half-Subtractors. Draw a block diagram showing its inputs and outputs. (5 Marks)

16.                        Compare and contrast the Half-Adder and Full-Adder circuits based on their functionality, number of inputs, and typical applications. (5 Marks)

17.                        A combinational circuit has three inputs A, B, C and one output F. The output F is ‘1’ when the binary input value is odd.

o    Construct the truth table for this circuit.

o    Derive the Sum-of-Products Boolean expression for F. (5 Marks)