Objective

The objective of this experiment is to demonstrate the logic inversion property of the 74LS04 NOT gate. When an input is HIGH (1), the output will be LOW (0), and when the input is LOW (0), the output will be HIGH (1).

Components Needed

• 1 x 74LS04 Hex Inverter IC
• 1 x LED (for output indication)
• 1 x Resistor (220Ω for the LED)
• 1 x Push Button (for input signal)
• 1 x Resistor (10kΩ for pull-down resistor)
• 1 x Breadboard
• Connecting Wires
• Power Supply (5V)

Circuit Diagram

Procedure

1. Place the 74LS04 IC on the breadboard, and connect pin 7 (GND) to the ground rail and pin 14 (VCC) to the 5V power rail.
2. Connect a push button to one of the input pins of the NOT gate (e.g., pin 1). This button will serve as the input signal.
3. Connect a 10kΩ resistor between the input pin (pin 1) and ground as a pull-down resistor to ensure a clean LOW signal when the button is not pressed.
4. Connect the output pin of the NOT gate (e.g., pin 2) to the anode of the LED.
5. Connect the cathode of the LED to ground through a 220Ω resistor.
6. Power the circuit by applying 5V to the IC, and observe the LED behavior:
• When the button is not pressed (input is LOW), the output of the NOT gate is HIGH, and the LED will light up.
• When the button is pressed (input is HIGH), the output of the NOT gate is LOW, and the LED will turn off.