Question
14. How are sequential circuits different from combinational circuits?
Answer
Sequential circuits:
The output of the sequential circuit is depends on the present input and past input. It is a function of present input and the previous input. To do this, the sequential uses a storage element to store the previous value.
Combinational circuit:
The output of the combinational circuit is depends only on the present input. If the input value of the circuit is changed, this shows direct impact on the output value.
Few differences between the sequential and combinational circuits are given as follows:
|
Sequential circuits |
Combinational Circuits |
|
The output is depends on the present input and previous input. |
The output is depends on the present input only. |
|
A feedback is required to input the previous element to generate the next output. |
Feedback is not necessary as the output directly depends on the input. |
|
The performance is slow because of the feedback. |
Faster performance is achieved. |
|
Complexity of the circuit is high. |
Complexity of the circuit is low. |
|
Flip-flops are building blocks to construct the sequential circuits. |
Logic gates are the building blocks to construct the combinational circuits. |