Basic Electricity

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The last page explained the Series Circuit. It works as it should, but sometimes we might want to leave one light on while we turn another off. We need another circuit to do that. And we have one. It's called a PARALLEL Circuit.

Here is a basic Parallel Circuit. We have added a second light bulb to the single light bulb we started with on the series circuit page. But notice now that the current that flows through the second bulb does not pass through the first. There are two current paths.

But this Parallel Circuit has the same problem that we found on the Series Circuit
when we connected just the light, There is no switch to turn the light Off.

There are two ways to fix this, both will work, but each will work differently. Remember the two lights we connected in series? The switch turned off both lights but when they were On they were both dim. With a Parallel Circuit they both receive the full voltage and are bright.

If we put the switch in the main line coming from the battery it will break the circuit
to both bulbs. One switch can control both lights at the same time.
Try it; Connect your lights as shown here.

But what if we want to turn one light off and on without affecting the other one? We can do that, too! The bottom drawing shows us how. Connect your two lights and switches as you see here. Notice that we have moved the first switch and added a second one.

Now we have two switches and two lights. But each one of those switches and light bulbs.
look just like what we saw back when we connected the series circuit, right?

EXACTLY! You recall that there is only one path in a series circuit. If we open the switch the light would go off. It still does, but only the light that is in series with it. The other remains lit. That is because the other light and switch is connected in Parallel with the first. This circuit is both Series and Parallel.

Click the Wizard for more about Parallel Circuits

When you have a circuit wired like this, it is called SERIES-PARALLEL.
Go ahead, connect your lights like this and try it for yourself.

After you have done this experiment, let's move along and review a few things we've learned.