The output of a sequential circuit depends on

Answer: both present and past input

Explanation:

• Key idea: A sequential circuit contains memory elements that store past inputs as the circuit's state. The output is determined by both the current input and this stored state.

• Contrast: A combinational circuit has no memory and its outputs depend only on the present input, but a sequential circuit uses memory so past inputs matter.

• Compact description: Output = f(current input, state); state_next = g(current input, state). The state captures the effect of past inputs.

• Example: A flip-flop stores a previous input value; a circuit built from flip-flops can produce outputs that depend on that stored value (past input) together with any new input.