Elenco Understanding Logic Gates and Circuits - Manual (Page 15)

Project 8: De Morgan’s Law
Negation of Disjunction
This circuit demonstrates De Morgan’s Law of
Negation of Disjunction which states that the
negation
of a disjunction is equivalent to
conjunction of the negations. Turn the slide switch
(S1) on. The green wire on the left connects the A
inputs of the top U15 module and the U17 module
(representing the A input in the diagrams below)
while the green wire on the right connects the A
inputs of the second U15 module and the U17
module (representing the B input in the diagrams
below). Connect the loose ends of the red wire and
the black wire to either high voltage (1) or low
voltage (0).
No matter what combination you
connect, the green LED and red LED will always
either both be on or both be off, demonstrating that
any combination of inputs to the two diagrams
always provides the same outputs.
Negation of Disjunction = Conjunction of Negations.
A
Q
B
=
A
Q
B
Same
Negation
of
Disjunction
Conjunction
of
Negations
1
1
4
U15
U16 U15
U15 U17
1 1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
3
3
2
3
2
3
3
3
2
3
2
2
2
3
3
3
2
4
1
15
1
5
2
3
4
1 2
3
4
5
1
0
A
B
Q
Q