A truth table shows how the outputs of a digital circuit is dependent upon its inputs.
It can be seen as the model theoretic *meaning* of the circuit.
Logicians also make use of truth tables.

Consider a half adder which adds bits `A`

and `B`

giving the sum `S`

and carry `C`

.
The truth table below shows each of the four different combinations of the inputs `A`

and `B`

and
the `S`

and `C`

outputs for each combination.

` A ` | ` B ` | ` S ` | ` C ` |
---|---|---|---|

`0` | `0` | `0` | `0` |

`0` | `1` | `1` | `0` |

`1` | `0` | `1` | `0` |

`1` | `1` | `0` | `1` |

Mano, M. Morris, and Kime, Charles R. *Logic and Computer Design Fundamentals. 2nd Edition.* Prentice Hall, 2000.

Kleitz, W. *Digital Microprocessor Fundamentals. 3rd Edition.* Prentice Hall, 2000.

Copyright © 2014 Barry Watson. All rights reserved.