Service manual

STP 11-25R13-SM-TG
Q - 22
e. NAND Function
. A NAND gate can be defined as the complement of an AND gate. Reviewing
the truth table for an AND gate, a truth table for the NAND gate can be written easily (Table Q-13).
Table Q-13. Truth Tables
(1) Nothing has changed except the outputs, which are inverted. There are two ways of
constructing this gate with AND, OR, and NOT gates.
(2) The first is to invert the inputs and feed them into an OR gate as shown in Figure Q-11.
Figure Q-11. NAND Gate
(3) From the truth table, you can see that this combination of gates will satisfy the definition of a
NAND gate. Waveform analysis will show the same fact as shown in Figure Q-12.
Figure Q-12. Waveform Analysis of NAND Gate
AND Table NAND Table
A B C
A B C
0 0 0 0 0 1
0 1 0 0 1 1
1 0 0 1 0 1
1 1 1 1 1 0