Difference Between Combinational And Sequential Circuits

“Difference Between Combinational And Sequential Circuits” is the most popular
question from digital electronics, which is asked in interviews. So to get a
better understanding of digital electronics circuits and designing, It is
necessary to know the difference between combinational and sequential circuits.
This is also the most important topic from interview’s perspective. So let’s get
started without further ado.

Combinational	Sequential
1. Output depends only on present input.	1. Output depends on present input and previous input.
2. It does not have any memory element.	2. It consists of a memory element.
3.No feedback path between input and output.	3. Feedback path is present between input and output.
4. Activating signal is an enabled input with level triggering.	4. Activating signal is a clock pulse with edge triggering.
5. Statements are executed sequentially (one after other).	5. Statements are executed parallelly (simultaneous) here.
6. Hence, blocking assignment is used for combinational circuits coding with the symbol ‘=’  for assignment.	6. Hence, non-blocking assignment is used for sequential circuits coding with symbol ‘<=’  for assignment.
7. Logic gates are the building blocks of these circuits.	7. Flip-flops are the building blocks of these circuits.
8.No clock signal is applied. Hence time-independent	8. Clock signal is applied. Hence, time-dependent.
9. Faster in speed.	9. Comparatively lower in speed.
10. Easy to design.	10. Much tougher to design compared to combinational circuits.
11. Example: Encoder, Decoder, Demultiplexer, Multiplexer, etc.	11. Example: Counters, Flip-flops, Registers, etc.
12. Basic Block diagram:	12. Basic Block diagram: