CUET PG 2026 — Computer PYQ

Solution

To identify which circuits are combinational, we must distinguish between the two main types of digital circuits:

1. Combinational Circuits: In these circuits, the output depends only on the current inputs. They do not have any memory or feedback loops.

• Half Adder: Adds two single-bit binary numbers. The output is strictly based on the current inputs.

• Full Adder: Adds three single-bit binary numbers. Like the half adder, it is memoryless.

2. Sequential Circuits: In these circuits, the output depends on the current inputs and the previous state (past history). They contain memory elements.

• SR Flip Flop: A basic memory element that "remembers" its state until it is reset or set.

• D Flip Flop: A memory element that captures the value of the D-input at a specific portion of the clock cycle.

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Comparison:

• A (Half adder) and C (Full adder) are Combinational.

• B (SR flip flop) and D (D flip flop) are Sequential.

Final Answer:

The correct option is (a) A, C.