Flashlight Circuit

A flashlight is a good example of a simple

circuit. Inside this flashlight there are two batteries

connected in series along with a light builb and

metal connecting all of the components. The

flashlight's on-off switch completes the circuit when

it is switched on by moving a piece of metal into

place, thus completing the metal circuit relaying the

battery potential difference to the light bulb.

The amount of current running through the circuit

is found with the equation V=IR where V is the

voltage of the battery and R is the resistance across

the light bulb. Because the batteries are connected

in series the power or P=IV of the light bulb is greater than it would be with just one battery. In

order for the light bulb to stay lit, the circuit must remain completed by the on switch so that the

current is able to flow and complete the circuit.

Also, the Potential difference or voltage across the battery must be countered by the resistance in

the lightbulb so the voltage in the wire as it returns to the battery is 0V.