AC/DC Circuits!

As our last unit, we learned about electricity, specifically DC circuits. DC circuits are electrical circuits that keep electrons in a direct and constant flow if the circuit is closed. Batteries are used to power these circuits. The current of the circuits is like the flow rate in plumbing pipes, the voltage is like the water pressure, and the resistance in each bulb is like the size of the pipe (friction, essentially).

This is a diagram of a DC circuit in series. In this circuit, the energy created by the batteries allow the electrons to flow through the circuit. The bulbs are dimmer than normal because the voltage is split between the two bulbs from the batteries. The current remains the same throughout because there is nowhere for it to split.The circuit is just one loop so the current stays constant even when the voltage changes due to the resistors. This is a series circuit because the electrons have only one "series" of wire to travel through. If one of them were to be removed, neither bulb would work because the bulb serves as a connection. The resistance of each bulb is like a friction that slows down the current and since it is in one series of wire, the current is slowed through the whole thing.

This is a diagram of a parallel DC circuit. This circuit is different because there are two paths for the electrons to flow. Unlike the first one, if one bulb is removed, the other one will not be affected because electrons still have a way to flow through the other one. The current isn't affected by the resistance of each individual bulb because the electrons come back together after they go through each individual bulb. This is why the bulbs are brighter. The voltage is like what water pressure would be in some plumbing pipes. Since there is a fork in the path, the water pressure remains the same, and then after it goes through the "friction" of the resistors, it just comes back together. The resistance of the bulbs does not play a huge role here because since there are two paths, the current doesn't affect each bulb.

Finally, we have a complex circuit, with a bulb in a series with two bulbs that are in parallel. As you can see, the two bulbs in parallel aren't as bright as they were before. This is because the bulb in circuit creates a voltage drop like in the first diagram, therefore making the bulbs in parallel dimmer. If one of the bulbs in parallel is removed, everything still works the same. However, if the bulb in series is removed, everything stops even when the other two are in parallel. This is because if the bulb in series were removed, the circuit would be incomplete. In this circuit, the bulb in series acts the same as the first diagram for the two parallel bulbs. The "friction" in the resistor of the bulb in series slows the current down so that when it gets to the parallel circuit, the current still splits like normal, but the current is slower to begin with.

The voltage and current are different in each of these because they all have different means of transporting the energy. When they're put together, it's a mixture of both ways to solve.