# Basic Circuits

After learning the basics of electricity, you might be wondering how to put all that information together into something useful. Be sure to read over the basics of electricity if need be; I'll write this essentially as a continuation from my "Basic Electricity" series.

There are two basic circuit structures in electronics; they are called series and parallel. In the world of electronics, you'll find many configurations and combinations of them; but as was the case with the three building blocks of volts, ohms, and amps ... everything will be built on these two fundamental structures.

#### Series Circuits

As you can see in the diagram to the right, the components of a series circuit are connected end to end. The electrical current must pass thru one device to get to the next, and so on.

There are a couple of simple mathematical rules that go along with series circuits (surprised?).

The current thru any chosen point will be equal to the current flowing at any other point. This is true, because there is one way in and one way out of each device. That means that if there is 1 Amp flowing thru Device 1, then there will be 1 Amp thru each of the other devices, and 1 Amp total being drawn from our supply. Think of it as a water fall - all the water that comes over the top is bound to land at the bottom.

The other rule we should know is that the voltages across each device will add up to the total voltage of the supply. Note, that does not mean each device will have an equal voltage - just that it will all add up to the source voltage. Think of it as ice cubes stacked up; the total height will be the thickness of each cube added together even though the cubes are not all the same size.

So, lets put that into a couple of formulas, of course.

#### I^{TOTAL} = I^{DEVICE 1} = I^{DEVICE 2} = I^{DEVICE 3} = I^{SOURCE}

and

#### V^{TOTAL} = V^{DEVICE1} + V^{DEVICE2} + V^{DEVICE3} = V^{SOURCE}

Hope those formulae don't look too scary; they are just a mathematical way of writing what was said in the previous two paragraphs. Typically, the superscripts would be shortened/abbreviated. To make the meaning of each term easier to read, I chose not to do that here ... but it does make them 'look' longer and more complicated than they really are.

Next, we I will discuss some real world series circuits.