Experiment No. 3 verifies half adders and full adders using basic and universal gates. It discusses the theory of multiplexers, which are devices that select between input signals and forward a single output. Multiplexers have select lines to choose the input line sent to the output. They are used to increase data transmission efficiency over networks. The document also contains circuit diagrams and outputs of half adders and full adders implemented using XOR, NAND, and NOR gates. Applications of multiplexers include increasing communication system efficiency, use in computer memory, and integrating multiple audio signals for telephone network transmission.

1. Experiment No. 3
OBJECTIVE:- Verification of Half Adder and Full Adder using basic gates and universal gates.
APPARATUS REQUIRED:- LTSpice
THEORY:- A multiplexer, also known as a data selector, is a device that selects between several
analog or digital input signals and forwards it to a single output line. It is combinational logic network
which has 2n
inputs, n select lines and has only one output.
A multiplexer of inputs has select lines, which are used to select which input line to send to the
output. Multiplexers are mainly used to increase the amount of data that can be sent over the network
within a certain amount of time and bandwidth.
Multiplexers are also known as “Data n selector, parallel to serial convertor, many to one circuit,
universal logic circuit”.
Fig 1: Block diagram of half adder Table 1: Truth table of half adder
INPUTS OUTPUTS
A B SUM CARRY
0 0 0 0
0 1 1 0
1 0 1 0
1 1 0 1
A B Cin S Cout
0 0 0 0 0

2. Fig 2: Block diagram of Full adder Table 2: Truth table of full adder
0 0 1 1 0
0 1 0 1 0
0 1 1 0 1
1 0 0 1 0
1 0 1 0 1
1 1 0 0 1
1 1 1 1 1

3. CIRCUIT DIAGRAM & OUTPUTS :-
1- Half Adder
Fig-3 Circuit diagram of half adder using XOR
Fig-4 Output of half adder using XOR

4. 2- Half Adder using NAND
Fig-5 Circuit of half adder using NAND
Fig-6 Output of half adder using NAND

5. 3- Half Adder using NOR Gate
Fig-7 Circuit of half adder using NOR
Fig-8 Output of half adder using NOR

6. 4- Full Adder
Fig-9 Circuit of Full adder using XOR
Fig-10 Output of Full adder using XOR

7. 5- Full Adder using NAND
Fig-11 Circuit of Full adder using NAND
Fig-12 Output of Full adder using NAND

8. 6- Full Adder using NOR Gate
Fig-13 Circuit of Full adder using NOR

9. Fig-14 Output of Full adder using NOR
Applications:
1. Multiplexer is used in communication systems to increase the efficiency of the communication
system by allowing the transmission of data, such as audio & video data from different channels
via cables and single lines.
2. It is used in computer memory.
3. It is used in telephone networks to integrate the multiple audio signals on a single line of
transmission.