Circuitry

Overview

Objectives/Goals I will investigate how connecting devices ( 3 light bulbs) in parallel affect the electric current in a circuit. Methods/Materials Method: 1) Attach voltage meter to a board and use this as a brightness tester. 2) Make a parallel curcuit by connecting two flashlight bulbs to a 1.5 V battery and measure the voltage with the meter. 3) Continue to add more bulbs (resistance) to the curcuit and compare any change in voltage. Record observations.4) Disconnect one bulb in the parallel circuit and measure any change in voltage. Materials: One piece of 6" by 12" wood board. Light bulbs(1.5 V) (4). Battery (1.5 V) (1). Voltage Meter. Pieces of insulated wire, each about 10 cm long (8). Battery holder. Minibulb sockets (4). Results As I added more light bulbs (resistance) to the circuit, the voltage on the meter became weaker. I also obvserved that the brightness of the bulbs got dimmer. When I disconnected one bulb from the circuit, the rest of the bulbs stayed lit and got brighter. Conclusions/Discussion When the resistance in a parallel circuit increases, the current decreases. When one bulb is disconnected, the circuit continues to work. Parallel circuits are used in homes and schools so that if one part of the building looses electricity the rest of the building will still have eletricity.

Competition history

• CSEF 2005 Electricity & Electronics · Entry J0709

Resources

• CSEF project summary ↗

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