**Silicon, Circuits, and the Digital Revolution**

**Introduction to Digital Logic: **
**AND Gate**

A: | B: | C: |
---|---|---|

(in) | (in) | (out) |

0 | 0 | 0 |

0 | 1 | 0 |

1 | 0 | 0 |

1 | 1 | 1 |

The AND operation has the usual logical significance -- the outcome is true if, and only if, both inputs are true. The symbol for AND looks like the "dot" representing the usual multiplication of two numbers; note that the truth table looks correct for multiplication of "0"s and "1"s.

Please note the connection between the NAND and the AND gate. The output of the NAND gate is opposite of the AND gate -- NAND stands for NOT AND. In digital logic NOT represents the opposite -- NOT true is false, NOT 1 is 0. The symbol for NOT is a bar over whatever quantity is being "NOTed." Compare the schematic symbols for NAND and AND -- the "bubble" near the output of the NAND gate represents the NOT operation.

Comments, suggestions, or requests to ghw@udel.edu.
"http://www.physics.udel.edu/~watson/scen103/colloq2000/and.html" Last updated May 4, 2000. © George Watson, Univ. of Delaware, 2000. |