Aim:

To study the behavior of bulbs connected in parallel and observe changes in brightness and voltage distribution.

Apparatus Required:

• Bulbs (same wattage) – 2 or more

• Lamp Holders

• Connecting Wires

• One way switch

• Fuse

• Power Supply (AC 230V)

• Voltmeter

• Ammeter

• Screwdriver, Wire Stripper

Procedure:

1. Turn Off Power Supply – Ensure the power source is switched off before making connections.

2. Fix the Lamp Holders – Mount the lamp holders on the wiring board.

3. Connect Bulbs in Parallel:

   • Connect all input terminals of the bulbs to the live wire of the power supply.

   • Connect all output terminals of the bulbs to the neutral wire of the power supply.

   • Use insulated copper wires for connections.

4. Connect to Power Source:

   • Attach the parallel connection to the live terminal of the power supply.

   • Connect the other end to the neutral terminal through a switch and a fuse.

5. Insert Ammeter in Series – Place an ammeter in series with the power supply to measure total current flow.

6. Insert Voltmeter Across Each Bulb – Place a voltmeter across individual bulbs to measure voltage drop.

7. Switch ON the Circuit – Turn on the power supply and observe the bulbs.

8. Switch OFF the Circuit – Ensure safety by switching off the power before making modifications.

Observations:

• Bulbs in parallel receive equal voltage but share the total current.

• If one bulb fails, the other bulbs continue to glow.

• Bulbs glow brighter compared to series connections as each bulb gets full voltage.

Precautions:

1. Ensure all connections are tight and secure to prevent loose contacts and sparking.

2. Use properly insulated wires to avoid short circuits and electric shocks.

3. Always switch off the power supply before making any wiring changes.

4. Use a fuse of appropriate rating to protect the circuit from overcurrent.

5. Avoid touching live wires while the circuit is powered on.

6. Verify voltage readings carefully using a properly calibrated voltmeter.

7. Ensure the bulbs are properly rated for the supply voltage to prevent damage.

8. Follow all safety protocols and use necessary protective equipment while working with electrical circuits.

Result:

The experiment demonstrates that in a parallel circuit, the same voltage is applied across all components, and the total current divides among them. The brightness of the bulbs remains unchanged regardless of the number of bulbs, unlike in a series circuit.

Circuit Diagram: