Difference between Combinational and Sequential Logic Circuit

In digital electronics, both combinational circuits and sequential circuits are the most widely used circuits. These are two broad categories of circuits defined in digital electronics where one type of circuit is independent of time and the other is dependent on time. So here this article gives the main key difference between combinational circuits and sequential circuits.

What is a combinational circuit?

The combinational circuit is the type of circuit in which the output is independent of time and only relies on the input present at that particular instant.

What are sequential circuits?

Sequential circuits are the type of circuit where output not only relies on the current input but also depends on the previous output.

Difference between combinational circuit and sequential circuits:

  • The combinational circuit is easier to design, use and handle, while a sequential circuit is not easier to design, used, and handle than the combinational circuit.
  • In combinational circuit clock signal are not required and it is not dependent on time, while the sequential circuit clock signal is required and it is dependent on time and clock so need triggering.
  • In the combinational circuit, elementary building blocks are only logic gates, while the sequential circuit element building blocks are flip-flops.
  • Combinational circuits are faster logic circuits while sequential circuits are slower than combinational circuits.
  • Combinational circuits the output depends only upon the present input and there is no need for feedback for input and output. So, the memory element is not required, In a sequential circuit the output depends upon both present input and present state, so the memory element is required to save the feedback state.