7. The logic and

The and more or more entrances and one way out gate.

The output has a high logical value (1) if all its inputs have a high logical value (1).

That is, if the entrance to and input B are at high level, the output will be at high level. Hence the name AND in English.

The symbol of the AND gate is as follows:

Puerta lógica AND de dos entradas.

Logic two-entry AND gate symbol.

The logical function of the and gate is represented by multiplication, so that the exit of the gate will be the logical multiplication of the entrances:

Out = A \cdot B

The Truth Table AND is as follows:

Tabla de verdad de la puerta lógica AND de dos entradas.

Truth Table of the Logic and two entries.

If the two tickets are worth one, the exit will be worth one, but if any entry is worth zero, the exit will be worth zero.

THE LOGIC gate NAND

The NAND logic gate has two or more entries and one way out.

The exit will be the same as that of an and, but inverted gate. In other words, the exit will only be worth zero when all tickets are worth one.

The NAND gate symbol is as follows:

Puerta lógica NAND de dos entradas.

Two -entry NAND logic symbol.

The logical function of the NAND gate is represented by means of a multiplication denied, so that the exit of the gate will be the logical multiplication of the entries that is finally invested:

Out = \overline {A \cdot B}

The Truth Table of the NAND gate is as follows:

Tabla de verdad de la puerta lógica NAND de dos entradas.

Truth Table of the logic NAND of two entries.

Simulation

In the following simulation we can see the functioning of the Logic Gate and, below, the operation of the NAND logic gate.

Exercises

  1. Explain with your words the functioning of the Logic Gate and.
  2. Draw the symbol of the Logic and two entries, its logical function and its truth table.
  3. Explain with your words the functioning of the NAND logic.
  4. Draw the NAND logic symbol of two entries, its logical function and its truth table.
  5. In the simulator adds an investment gate at the exit of the and checks that your answer is equal to that of the Nand gate.
  6. Draw a logical and three entries, its logical function and its truth table.