Question

Which of the following are characteristics of a Combinational Circuit?
• [A.] Output depends only on present input
• [B.] Output depends only on past input
• [C.] It has no memory element
• [D.] It uses flip-flops to store data
Choose the correct answer from the options given below:

• A. A and B only
• B. A and C only
• C. B and D only
• D. C and D only

Hint:

Combinational = No memory, Sequential = Has memory (flip-flops).

Answer 1

The Correct Option is B

Concept: Digital circuits are broadly classified into:
• Combinational Circuits: Output depends only on present inputs, no memory.
• Sequential Circuits: Output depends on present as well as past inputs, includes memory elements.

Step 1: Analyze statement A.
Output depends only on present input.
This is the defining property of combinational circuits.
\[ \text{Hence, A is correct.} \]

Step 2: Analyze statement B.
Output depends only on past input.
This is incorrect because combinational circuits do not depend on past inputs at all.
\[ \text{Hence, B is incorrect.} \]

Step 3: Analyze statement C.
It has no memory element.
Combinational circuits do not store any information; they compute outputs instantly.
\[ \text{Hence, C is correct.} \]

Step 4: Analyze statement D.
It uses flip-flops to store data.
Flip-flops are memory elements used in sequential circuits, not combinational circuits.
\[ \text{Hence, D is incorrect.} \]

Step 5: Final conclusion. \[ \boxed{\text{Correct statements are A and C}} \] \[ \boxed{(2)} \]