# Triple 3-Input NOR Gates

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## Aim

To study and verify the truth table of Triple 3-Input NOR Gates

## Learning Objectives

1. To understand the behavior and demonstrate the operation of Triple 3-Input NOR Gates
2. To apply knowledge of the fundamental gates to create truth tables.
3. To develop digital circuit building and troubleshooting skills.
4. To understand key elements of TTL logic specification or datasheets.

## IC Used

For Triple 3-Input NOR Gates:
IC NumberIC Name
74LS27Triple 3-input NOR Gates

## Procedure

1. Place the IC on IC Trainer Kit.
2. Connect VCC and ground to respective pins of IC Trainer Kit.
3. Implement the circuit as shown in the circuit diagram.
4. Connect the inputs to the input switches provided in the IC Trainer Kit.
5. Connect the outputs to the switches of O/P LEDs
6. Apply various combinations of inputs according to the truth table and observe the condition of LEDs.
7. Note down the corresponding output readings for various combinations of inputs.
8. Power Off Trainer Kit, disconnect all the wire connections and remove IC's from IC-Base.

## Theory

NOR GATE - ​ It is a digital circuit that has two or more inputs and produces an output, which is the inversion of logical OR of all those inputs.

Logic NOR Gates are available using digital circuits to produce the desired logical function and is given a symbol whose shape is that of a standard OR gate with a circle, sometimes called an “inversion bubble” at its output to represent the NOT gate symbol with the logical operation of the NOR gate.

As with the OR function, the NOR function can also have any number of individual inputs and commercial available NOR Gate IC’s are available in standard 2, 3, or 4 input types. If additional inputs are required, then the standard NOR gates can be cascaded together to provide more inputs.

Boolean Expression Y = (​ A+B+C)​'

"If A and B and C are NOT true, then Y is true"

NOR gate operation is same as that of OR gate followed by an inverter. That’s why the NOR gate symbol is represented like that.

## Precautions

1. Make the connections according to the IC pin diagram.
2. The connections should be tight on trainer kit.
3. The Vcc and ground should be applied carefully at the specified pin only.

## Conclusion

We have learned the Triple 3-Input NOR Gates IC according to the IC pin diagram.