Our latest unit in physics class is Electricity. An electric current is a flow of electric charge. A conductor allows energy to flow easily while an insulator makes energy flow difficult. The current of a circuit is equal to the voltage divided by the resistance. Each energy source, such as a battery, provides voltage. Each resistor provides resistance and lowers the current.
There are three types of circuits. They are series, parallel, and combination (a mixture of the two). In series, resistance lowers current. In parallel, resistance increases current.
These two light bulbs are connected in series. That means that the resistance is higher, because in series, with every new bulb added, the resistance grows higher. Because of this, the current is lower, which is why the bulbs are less bright than the bulb in the previous picture. If one of the bulbs is removed, the circuit would be interrupted and the other bulb would go out, too. The current is the same in both of the bulbs. The voltage would depend on the voltage in each battery. These would be added together and equal the total voltage in the circuit.
These two bulbs are connected in parallel, so with each new bulb added, the resistance is lowered. The current would be higher in this circuit than the previous one because of this. If one bulb was removed, the other bulb would stay lit because the circuit would not be interrupted. If the two bulbs had a different amount of resistance, then the current in the bulbs would be different. The voltage in each light bulb would be different if the resistance in each bulb is different.
This is a complex series. It has two bulbs connected in parallel, which is connected in series to one other bulb. The voltage would be different in the two parallel bulbs if the resistance was different. The two bulbs connected in series would have the same voltage. The current would be the same between those two bulbs as well. The resistance is lowered for each parallel bulb added and it is increased for each series bulb added. The current in this circuit would equal the voltage of each battery added together divided by the equivalent resistance. If the series bulb is removed, the circuit would be interrupted and the other lights would go out. If the bulbs connected in parallel were taken out, the circuit would not go out because the circuit would not be broken.
