Experiment No. 5 bsc.3rd semester
Object
To verify NOR gate as a universal gate .
Apparatus Required
Logic gate kit . connecting Wires , power
supply .
Theory
We can Create any logical Boolean expression for any
other gates by using NOR gate . therefore NOR gate is called ‘ universal Gate ‘
NOR gate
The NOR or “ NOT OR “ funcation is a Connected together in
series , the logic NOR funcation can be expressed by Boolean expression of A
(bar) + B (bar)
Y = A (bar) + B (bar)
1.
NOR as
a NOT gate
NOT can be implemented using NOR gate as
the Boolean expression for NOT gate is .
Y = Ᾱ
Truth table
|
Input |
Output |
|
A |
Y = Ᾱ |
|
0 |
1 |
|
1 |
0 |
2.
NOR
Gate as OR Gate
OR gate can be implemented using NOR gate
.
Y = A
(bar) + B (bar) = A + B { as Ᾱ = A
Truth table
|
Inputs |
Output |
|
|
A |
B |
Y = A + B |
|
1 |
0 |
1 |
|
0 |
1 |
1 |
|
1 |
1 |
1 |
|
0 |
0 |
0 |
3.
NOR
gate as AND gate
AND gate can be implemented using NOR gate by using
De Morgan ‘ s theorem .
1.
Y = A
(bar) + B (bar) = A (bar) . B (bar) = A . B
Truth table
|
Inputs |
Output |
|
|
A |
B |
Y = A . B |
|
0 |
0 |
0 |
|
1 |
1 |
1 |
|
1 |
0 |
0 |
|
0 |
1 |
0 |
Observation
1.
Truth table for
NOT gate implemented by using NOR gate.
|
Input |
Output |
|
A |
Y = Ᾱ |
|
0 |
1 |
|
1 |
0 |
2.
Truth table for
OR gate implemented by using NOR gate .
|
Inputs |
Output |
|
|
A |
B |
Y = A + B |
|
1 |
0 |
1 |
|
0 |
1 |
1 |
|
1 |
1 |
1 |
|
0 |
0 |
0 |
3.
Truth table for
AND gate implemented by using NOR gate .
|
Inputs |
Output |
|
|
A |
B |
Y = A . B |
|
0 |
0 |
0 |
|
1 |
1 |
1 |
|
1 |
1 |
1 |
|
0 |
1 |
0 |
Result
NOR gate as a universal verified .
Precautions
1.
Connections should
be proper and tight .
2.
Switch ‘ON’ the
power after completing the circuit .
3.
Carefully read
the logic ‘high’ and sow conditions .
Logic circuit of De – Morgan ‘ s 1st theorem
