ABSTRACT
The digital circuits we have examined so far do not possess any memory. That is, the output of the combinational circuit at any time is a function of the inputs at that time. In practice, most digital systems contain memory elements in addition to the combinational logic portion, thus making them sequential circuits. The output of a sequential circuit at any time is a function of its external inputs and the internal state at that time. The state of the circuit is dened by the contents of the memory elements in the circuit and is a function of previous states and inputs to the circuit.
