This investigatory project on logic gates discusses their fundamental principles, types, and functions. It highlights the role of logic gates in digital circuits, emphasizing their significance in modern electronics and the construction of integrated circuits. The project acknowledges the support of teachers, parents, and various online resources utilized during its completion.

1. TOPIC:- LOGIC GATES
TEACHERS SIGNATURE :-
DONE BY:-- K. AVNEESH NATHAN
CLASS:- XII ‘A’
ROLL NO :-

2. ACKNOWLEDGEMENT
IT gives me immense pleasure to present the
Investigatory Project on LOGIC GATES. It
would not have been possible without the kind
support of my teacher in charge, Mrs.
POOJA KUMARI under whose guidance and
constant supervision the project was brought to
the present state.
I would also like to express my gratitude
towards my parents for their kind co-operation
and encouragement which helped me in the
completion of this project.
I am also thankful to the C.B.S.E for giving me
such an amazing opportunity for making this
project, and giving suitable instructions and
guidelines for the project.
Last but not the least, I thank my friends who
shared necessary information and useful web
links for preparing my project.
Thanks again to all.

3. INDEX PAGE

4. INTRODUCTION
GATE: - A logic gate is a digital circuit, which works
according to some logical relationship between input
and output signal. It may have one or more inputs, but
it has only one output. Most of the logic gates have
two inputs. We know that a digital signal has two only
levels i.e. either HIGH or LOW. Normally, a +5V supply
is referred to as HIGH and is represented by the binary
number 1 . On the other hand, 0 V is termed as LOW
and is represented by the binary number 0.
BOOLEAN EXPRESSION :- The logical relationship
between input and output signals .
TRUTH TABLE :- The truth table of a logic gate is a table
that shows all the input and output combinations for
the logic gate. It is also called the table of
combinations.
BOOLEAN ALGEBRA:- The algebra which is based on
the binary nature of the logic gates.

5. TYPES OF LOGIC GATES
AND Gate
OR Gate
NOT Gate
A
B
C
A
B
C
A C
NAND Gate
A
B
C
NOR Gate
A
B
C
Exclusive - OR Gate
A
B
A B=C

6. AND GATE
The AND gate implements the Boolean AND
function where the output only is logical 1 when all
inputs are logical 1.
The standard symbol and the truth table for a two
input AND gate is:
BOOLEAN EXPRESSION FOR AND
The Boolean expression for the AND gate is R=A.B

7. OR GATE
The OR gate implements the Boolean OR function where
the output is logical 1 when just input is logical 1.
The standard symbol and the truth table for a two input
OR gate is:
BOOLEAN EXPRESSION FOR OR
The Boolean expression for OR gate is R=A+B

8. NOT Gate
The NOT gate implements the Boolean NOT function
where the output is the inverse of the input.
The standard symbol and the truth table for the NOT
gate is:
BOOLEAN EXPRESSION FOR NOT
Boolean expression for the NOT gate R= -A

9. NAND GATE
The NAND gate is an AND gate followed by a NOT gate.
The output is logical 1 when one of the inputs are logical
The standard symbol and the truth table for the NAND
gate is:
TRUTH TABLE FOR NAND

10. NOR GATE
The NOR is a combination of an OR followed by a NOT
gate. The output is logical 1 when none of the inputs are
logical 0
The standard symbol and the truth table for the NOR
gate is:
TRUTH TABLE FOR NOR

11. Transformation of NAND gate into other
basic gates
1.Construction of NOTgate from NAND gate
Where, X = A NAND A
So, we feed A as input to the NAND gate. The output X
is the final result which is same as a NOT gate.

12. 2.Construction of AND gate using NAND gate
Where, R = A NAND B
And, X = R NAND R
So, we feed A and B as input to the first NAND gate. The
outputof the first NAND gate R then becomes input for
the second NAND gate. And the output of the second
NAND gate X is the final result which is same as an
AND gate.

13. 3.Construction of OR gate using NAND gate
Where, A' = A NAND A
And, B' = B NAND B
And, X = A' NAND B'
So, we feed A as input to the first NAND gate and B as
input to the second NAND gate. The output of the first
NAND gate A' and the outputof the second NAND gate
B' becomes input for the third NAND gate. And output
of the third NAND gate X is equivalent to an OR gate.

14. CONCLUSION
Logic gates are used to develop many IC
circuits or microchips in today’s modern
world.
NAND and NOR gate are known as
Universal gates because we can
construct all the gates using this 2 gates
alone.
Without logic gates the electronics
world would be nearly incomplete!

15. BIBLIOGRAPHY
This project would have been nearly
impossible without the help of the
following websites:-
1. DYclassroom.com
2. Wikipedia, the free encyclopedia
3. NCERT physics textbook {class 12}
4.www.electronicshub.org
My special thanks to the up loader of
information on these websites.
If considered I have used everything that
GOOGLE provided……