- To understand the behavior and demonstrate the operation of Dual 4-Input NAND Gates
- To apply knowledge of the fundamental gates to create truth tables.
- To develop digital circuit building and troubleshooting skills.
- To understand key elements of TTL logic specification or datasheets.

IC Number | IC Name |
---|---|

74LS20 | Dual 4-Input NAND Gates |

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

NAND gate is a digital circuit that has two or more inputs and produces an output, which is the inversion of logical AND of all those inputs.

Logic NAND Gates are available using digital circuits to produce the desired logical function and is given a symbol whose shape is that of a standard AND gate with a circle, sometimes called an "inversion bubble" at its output to represent the NOT gate symbol with the logical operation of the NAND gate.

As with the AND function seen previously, the NAND function can also have any number of individual inputs and commercial available NAND Gate IC's are available in standard 2, 3, or 4 input types. If additional inputs are required, then the standard NAND gates can be cascaded together to provide more inputs.

Boolean Expression **Y = (A.B.C.D)'**

**"If either A or B or C or D are NOT true, then Y is true"**

NAND gate operation is same as that of AND gate followed by an inverter. That's why the NAND gate symbol is represented like that.

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

### 2-Input NOR Gate

#### Aim: To study and verify the truth table of 2-Input NOR Gate.

**ICs used**: 74LS02### Hex Inverters with Open-Collector Outputs using 74LS05

#### Aim: To study and verify the truth table of Hex Inverters with Open-Collector Outputs using 74LS05.

**ICs used**: 74LS05### Quad 2-input NAND Gates with Open-Collector Outputs using 74LS03

#### Aim: To study and verify the truth table of Quad 2-input NAND Gates with Open-Collector Outputs using 74LS03.

**ICs used**: 74LS03### Implementation of Ex-NOR Gate using NAND gate

#### Aim: To study and verify the Implementation of Ex-NOR Gate using NAND gate.

**ICs used**: 74LS00### 2-Input AND Gate

#### Aim: To study and verify the truth table of 2-Input AND Gate.

**ICs used**: 74LS08