Sequential Logic Circuit Identification

Digital logic circuits are categorized into two main types:

• Combinational Circuits: The output is solely determined by the present combination of inputs. These circuits lack memory.
• Sequential Circuits: The output depends not only on the current inputs but also on the previous state or history of inputs. These circuits incorporate memory elements.

Analyzing the Options

We examine each option to determine its type:

• Full adder: Computes the sum and carry of two binary numbers plus a carry-in. Its output depends only on the current inputs, making it a combinational circuit.
• Multiplexer: Selects one of several input signals and routes it to a single output based on select lines. It operates based only on current inputs, classifying it as a combinational circuit.
• Flip-flop: A fundamental building block for memory in sequential circuits. It stores a single bit of information and its output depends on clock signals and previous states, making it a sequential circuit.
• Decoder: Converts coded input (like binary) into a specific output signal. Its operation relies solely on the current input, thus it's a combinational circuit.

Identifying the Sequential Circuit

The Flip-flop stands out as the sequential logic circuit because it utilizes internal memory to store state information, influencing future outputs based on past inputs and clock signals.