**Full Adder-**

- Full Adder is a combinational logic circuit that is used for the purpose of adding two single bit numbers with a carry.
- Thus, Full Adder has the ability to perform the addition of three bits unlike half adder which can add only two bits.
- It contains 3 inputs and 2 outputs (sum and carry).

**Designing a Full Adder-**

**Step-01:**

Identify the input and output variables-

- Input variables = A , B , C
_{in }(either 0 or 1) - Output variables = S , C
_{out}where S = Sum and C_{out}= Carry

**Step-02:**

Draw the truth table-

Inputs | Outputs | |||

A | B | C_{in} | C_{out} (Carry) | S (Sum) |

0 | 0 | 0 | 0 | 0 |

0 | 0 | 1 | 0 | 1 |

0 | 1 | 0 | 0 | 1 |

0 | 1 | 1 | 1 | 0 |

1 | 0 | 0 | 0 | 1 |

1 | 0 | 1 | 1 | 0 |

1 | 1 | 0 | 1 | 0 |

1 | 1 | 1 | 1 | 1 |

**Truth Table**

**Step-03:**

Draw the K-maps using the above truth table and determine the simplified Boolean expressions-

**Step-04:**

Draw the logic diagram-

**Logic Diagram**

Here, Full Adder has been implemented using 1 XOR gate, 3 AND gates and 1 OR gate.

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Summary

Article Name

Full Adder

Description

Full Adder is a combinational logic circuit that is used for the purpose of adding two single bit numbers with a carry. Full Adder has the ability to perform the addition of three bits unlike half adder. It contains 3 inputs and 2 outputs (sum and carry).

Author

Akshay Singhal

Publisher Name

Gate Vidyalay

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