Resistance and Ohm’s Law
To determine the voltage, resistance and current in a parallel, series and series-parallel circuit.
In everyday life, electricity is being used for the purpose of things like powering electronics. Electricity itself is a flow of electric charge (Millikan 2000). The movement of the electrically charge particles such as electron are best defined as the electric current. For the current to flow, it requires a pathway, in which a circuit is required as it provides that particular pathway (Millikan 2000).
There are different types of electric circuit as they can all be connected in many different ways. The two most common and simplest one are series and parallel (Young 2011) circuit. In a series circuit the components connected to that circuit are connected along a single pathway, sharing voltage. However for parallel circuit, the components connected individually receives the exact same voltage.
In the experiment, the components used to conduct the electric currents are light bulb, where the source of the voltage is received from AA batteries. In order to determine the current of the light bulb, Ohm’s Law must be used, where he stated that for the conductors of electricity, the electric currant, which flows through the conductors, is directly proportional to the voltage applied to them (Young 2011).
V = I x R
Where I = Current (amps)
V = voltage (V)
R = Resistance (Ω)
This equation can be used to determine the electric current of the circuit and light bulb, given the voltage and resistance.
- As shown in the diagram below, connect the wire to the bakelite bulb holder, while making sure that the bulb is screwed on.
- Using the multimeter measure the resistance of each bulb.
- Then connect the AA switched battery enclosure to the bulbs as shown in the diagram below while making sure that the batteries are inserted and switched on.
- Using the multimeter measure the voltage of the power supply, bulb 1 and bulb 2 by attaching the red cable to red and black cable to black.
- Measure the current in the series circuit by switching off and on the power supply and connecting the multimeter to the cables as show in the diagram below. (Note: make sure the multimeter is set to 200mA)