An adder is a digital circuit that performs addition of numbers. In many computers and other kinds of processors adders are used in the arithmetic logic units or ALU. They are also utilized in other parts of the processor, where they are used to calculate addresses, table indices, increment and decrement operators, and similar operations. Although adders can be constructed for many number representations, such as binary-coded decimal or excess-3, the most common adders operate on binary numbers. In cases where two's complement or ones' complement is being used to represent negative numbers, it is trivial to modify an adder into an adder– subtractor . Other signed number representations require more logic around the basic added.

1. Integrated project
On
Two bit adder
BE(ECE/7-1)
Submitted by –
Sumit Bansal – B130020009

2. ACKNOWLEDGEMENT
• We owe are gratitude towards CHITKARA
UNIVERSITY for giving us the opportunity to
present this project .
• We want to thank our project guide and our
BEEE teacher Mrs. Minaxi Dassi ma’am ,for
providing us the necessary information and
help whenever required .
• We also want to thank our parents and our
friends for their support.

3. CONTENTS
• Aim
• Introduction
• Components Used
• Half Adder
• Logic Approach
• 1. Logic Gates
• 2. Logic Diagram
• Circuit Diagram
• Truth Table
• Conclusion
• References

4. AIM
To construct a two bit adder using Switches as input
and Led’s As output

5. INTRODUCTION
The Adder is a digital circuit which forms the sum
and carry of two or more numbers. Adder circuits are
essential inside microprocessors as part of the ALU,
or arithmetic logic unit, where the processing and
manipulation of binary numbers takes place.

6. COMPONENTS USED
• RESISTOR: A resistor is a passive two-terminal
electrical component that implements electrical
resistance as a circuit element. Resistors act to reduce
current flow, and, at the same time, act to lower
voltage levels within circuits. We have used one 1M
ohm resistor and five 100 ohm resistors.
• IC: An integrated circuit or monolithic integrated
circuit (also referred to as an IC, a chip, or a microchip)
is a set of electronic circuits on one small plate ("chip")
of semiconductor material, normally silicon . We have
used (CMOS) 7486 and (CMOS) 7408.

7. • LED: A light-emitting diode (LED) is a two-lead
semiconductor light source that resembles a basic pn-
junction diode, except that an LED also emits light. When
an LED's anode lead has a voltage that is more positive
than its cathode lead by at least the LED's forward voltage
drop, current flows.
• DIP SWITCH: A DIP switch is a manual electric switch that
is packaged with others in a group in a standard dual in-
line package (DIP). The term may refer to each individual
switch, or to the unit as a whole.
• Diode : In electronics, a diode is a two-terminal electronic
component with asymmetric conductance; it has low
(ideally zero) resistance to current in one direction, and
high (ideally infinite) resistance in the other .

8. HALF ADDER

9. The addition of two 1-bit binary numbers looks like...
To let the addition of two 1-bit numbers be
done by a logic circuit, you need to look at
the truth table...
If you are only interested in a 1-bit
response Q, you only need
an XOR operation.
However, if you add up 1 and 1, the answer
is more complicated. A 1 must
be transferred to the next digit. This bit is
called a Carry-Bit. As the output of a logic
circuit, it is indicated with CO (Carry Out).
The result of CO is realized with
an AND operation.

10. Logic Gates
AND Gate : The AND gate is a basic digital logic gate that
implements logical conjunction- it behaves according to the truth table to
the right. A HIGH output (1) results only if both the inputs to the AND gate
are HIGH (1). If neither or only one input to the AND gate is HIGH, a LOW
output results . The CMOS IC used for AND gate is 7408, it’s a quad (two
input) AND gate IC .

11. OR GATE: The OR gate is a digital logic gate that implements logical disjunction -
it behaves according to the truth table to the right. A HIGH output (1) results if
one or both the inputs to the gate are HIGH (1).The IC used for OR Gate is 7432
but we have used diode logic
instead of IC .

12. XOR Gate: The XOR gate (sometimes EOR gate, or EXOR gate) is a digital logic
gate that implements an exclusive or; that is, a true output (1/HIGH) results if
one, and only one, of the inputs to the gate is true. If both inputs are false
(0/LOW) or both are true, a false output results. XOR represents the inequality
function, i.e., the output is true if the inputs are not alike otherwise the output
is false. A way to remember XOR is "one or the other but not both ". The CMOS
IC used for XOR Gate is 7486, it’s a quad XOR Gate IC .

13. LOGICAL
APPROACH
Logic Diagram

14. CIRCUIT DIAGRAM

15. TRUTH TABLE

16. CONCLUSION
Adders are widely used in many electronic devices. Adders
can be used to add numbers, subtract numbers (negative
addition), multiply (repetitive addition) as well as divide
numbers (repetitive subtraction).
The limitation of this project is that it can only compute sums
up to a maximum value of 7.
Adders form an integral part of ALU’s [Arithmetic Logic Unit]
and are widely used in high-performance DSP Applications.
[Digital Signal Processing] .

17. REFERENCES
• www.play-hookey.com
• www.howstuffworks.com
• “Introduction to Digital Systems” – University of
Texas at Dallas
• www.doctronics.co.uk