Aim : Verification of Logic Gates.
Components Required
Components required for verification of logic gates are –
1) IC 7404 Hex inverter ( NOT Gate )
2) IC 7408 ( AND Gate )
3) TC 7432 ( OR Gate )
4) IC 7486 ( XOR Grate )
5) IC 7402 ( NOR Gate )
6) IC 7400 ( NAND Gate )
7) Electronic trainer bound
8) Connecting wires
Theory
These are the fundamental building blocks of the digital system. It produces one output level I when some combination of input levels is present. The three basic types of logic gates AND, OR and NOT Gate. A table which lists all variable inputs and corresponding output is called truth table. The variables are binary, logic 1 is designated as ON or High State. Whereas logic 0 as off Low state.
NOT Gate ( IC 7404 )
A NOT gate is also known as inverter. It has one input and one output. Its output is complemented of its input.
Truth table for NOT Gate
|
Input |
Output |
|
1 |
0 |
|
0 |
1 |
IC 7404 Pinout
AND Gate ( IC 7408 )
An AND Gate has two or more inputs but only one output. The output assumes logic 1 state, only when all of its input is at logic 1 state. The output assumes the logic 0 state even if one of its inputs is at logic 0 state.
Truth Table for AND Gate
|
Input A |
Input B |
Output Y |
|
0 |
0 |
0 |
|
0 |
1 |
0 |
|
1 |
1 |
1 |
|
1 |
0 |
0 |
IC 7408 Pinout
OR Gate ( IC 7432 )
The OR Gate may have two or more inputs and only output. The output assumes the logic 1 state, even if one of its inputs is at logic 1 state. Its output assumes logic O state, only when each of its input logic 0 state.
Truth table for OR Gate
|
Input A |
Input B |
Output Y |
|
0 |
0 |
0 |
|
0 |
1 |
1 |
|
1 |
1 |
1 |
|
1 |
0 |
1 |
IC 7432 Pinout
NOR Gate ( IC 7402 )
NOR means NOT + OR, so a NOR Gate is a combination of an OR Gate and NOT Gate. The output is at logic 1 state, only when each of its input are any in logic 0 level for other combination of inputs, the output is at logic zero state. It is a universal gate.
Truth table for NOR Gate
|
Input A |
Input B |
Output Y |
|
0 |
0 |
1 |
|
0 |
1 |
0 |
|
1 |
1 |
0 |
|
1 |
0 |
0 |
IC 7402 Pinout
NAND Gate ( IC 7400 )
NAND means NOT + AND, so a NAND Grate is a combination of an AND Gate and NOT Gate. The Output logic zero state only when all of its input is in logic 1 level. any for other combination of inputs the output of NAND Gate is at logic 1 level. It is a Universal gate.
Truth table for NAND Gate
|
Input A |
Input B |
Output Y |
|
0 |
0 |
1 |
|
0 |
1 |
1 |
|
1 |
1 |
0 |
|
1 |
0 |
1 |
IC 7400 Pinout
XOR Gate ( IC 7486 )
The EX-OR operation is widely used in digital circuits. When both the input is in same logic state ( 0 or 1 ) the output of EX-OR is in logic 0 state, whereas when the inputs are not in same logic state i.e., if one of them is zero and the other is 1 the output is in logic 1 state.
Truth table for NAND Gate
|
Input A |
Input B |
Output Y |
|
0 |
0 |
0 |
|
0 |
1 |
1 |
|
1 |
1 |
0 |
|
1 |
0 |
1 |
IC 7486 Pinout
Procedure
- Fix the IC on the trainer board.
- Carry out the connections and setting.
- 5v dc supply was applied to pin no. 14 where as pin 7 was connected to common terminal ground.
- Logic inputs are applied to input terminal whereas outputs were taken from the corresponding outputs. output probs logic 1 through set input & logic 0 through clear input. For output, red LED implies logic 1 & green led implies logic 0.
- Similarly, all gates of on IC are green LED.
The result of the gates was verified according to the truth table of the corresponding gates.
Result & Conclusion
The result of all gates as observed was in accordance with their respective truth table, describing their behaviour.
Precaution
- All the pins of on IC should be checked before using.
- IC should be properly fixed. on trainer board and power supply to the pin 14 should not exceed from 5v dc.
- Connection should be made tightly.
- Power supply should be given to the trains board only after connections are made.
- Insulation in connection should be avoided.
Author
Akash Sharma
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