Sequence Logic Circuits

Class - BCA I year

Subject - Computer System Architecture 

Subject type - Major I

Compiled by -Asst Professor Sulochana Patidar 

Sequential circuits are digital circuits that store and use previous state information to determine their next state. They are commonly used in digital systems to implement state machines, timers, counters, and memory elements and are essential components in digital systems design.

Sequential circuits are commonly used in digital systems to implement state machines, timers, counters, and memory elements.

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.

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 circuit is a combinational logic circuit that consists of inputs variable (X), logic gates (Computational circuit), and output variable (Z). 

A combinational circuit produces an output based on input variables only, but a sequential circuit produces an output based on current input and previous output variables. That means sequential circuits include memory elements that are capable of storing binary information. That binary information defines the state of the sequential circuit at that time. A latch capable of storing one bit of information.

 

As shown in the figure, there are two types of input to the combinational logic : 

External inputs which are not controlled by the circuit.

Internal inputs, which are a function of a previous output state.

Secondary inputs are state variables produced by the storage elements, whereas secondary outputs are excitations for the storage elements