Unlike combinational circuits, which only depend on the current input values to produce

outputs, sequential circuits depend on both the current inputs and the previous state stored in

memory elements. Sequential circuits are commonly used in digital systems to implement state

machines, timers, counters, and memory elements. In a processor, the control unit is a sequential

circuit while the data$-$path is usually a combinational circuit. The memory elements in sequential

circuits can be implemented using flip$-$flops, which are circuits that store binary values and

maintain their state even when the inputs change