# Difference Between Combinational and Sequential Circuit

## Combinational and Sequential Circuit Difference

The Key Difference Between Combinational and Sequential Circuit in a Combinational Circuit output is dependent only on the inputs at the same instant of time. whereas Sequential Circuit output depends not only on the present inputs but also on the past history of inputs.

### Comparison Chart

Combinational Circuit Sequential Circuit
1 It does not contain memory elements. It contains memory elements.
2 Output depends on the present state of input only. Output depends not only on the present inputs but also on the past history of inputs.
3 Its behavior is described by the set of output functions. Its behavior is described by the set of next-state (memory) functions and the set of output functions.
4 Do not use the Feedback path. Use Feedback path.
5 Does not require a clock signal. Most sequential circuits use a clock signal.
6 Faster than the sequential circuit. Slower than the combinational circuit.
7 Example: Adder, Subtractor, MUX, Encoders, etc. Example: Flip Flops, Registers, Counters, etc.

### Combinational Circuit

• A combinational circuit can be defined as a circuit whose output is dependent only on the inputs at the same instant of time.
• Example of Combinational Circuit
• Half Adder
• Full Adder
• Half Subtractor
• Full Subtractor

### Sequential Circuit

• A sequential circuit can be defined as a circuit whose output depends not only on the present inputs but also on the past history of inputs.
• Example of Sequential circuit.
• Flip-Flops
• Registers
• Counters