Question

Arrange these digital logic building blocks in order of increasing complexity: 
A. Multiplexers 
B. Sequential logic circuits (e.g., counters) 
C. Combinational logic circuits (e.g., adder) 
D. ALU (Arithmetic Logic Unit) 
Choose the correct answer from the options given below:

• A. A, B, C, D
• B. A, B, D, C
• C. C, A, B, D
• D. C, A, D, B

Hint:

Complexity order: Combinational < Specialized (MUX) < Sequential < ALU.

Answer 1

The Correct Option is C

Concept: Digital systems are built hierarchically from simple to complex components:
• Basic combinational circuits form the foundation
• More specialized combinational units come next
• Sequential circuits add memory and complexity
• ALU is a highly integrated and complex unit

Step 1: Understand each component
• Combinational circuits (Adder): These are basic circuits that perform operations based only on inputs. They are fundamental building blocks.
• Multiplexer: A multiplexer is a slightly more structured combinational circuit used for data selection. It is more specific and slightly more complex than basic adders.
• Sequential circuits (Counters): These circuits include memory elements (flip-flops) and depend on past states, making them more complex.
• ALU (Arithmetic Logic Unit): ALU combines multiple arithmetic and logical operations and integrates many circuits, making it the most complex among these.

Step 2: Arrange in increasing complexity \[ \text{Combinational} \rightarrow \text{Multiplexer} \rightarrow \text{Sequential} \rightarrow \text{ALU} \] \[ C \rightarrow A \rightarrow B \rightarrow D \]

Step 3: Final Answer \[ \therefore \text{Correct answer is (C)} \]