Lesson 5: Series and Parallel Circuits

Engage

Why do you think we dont just draw circuits the way we see them?

Why do we use special keys?

New Information

Drawing Circuits

Drawing circuits is quite easy, all you need to do is use lines and symbols connected together.

The lines you draw represent the wires in the circuit, the symbols represent devices or special tools.

How to take notes for this section

For this section, its a good idea to use a table to take you notes. 

Here is an example I have prepared (image on the right)

Series Circuits

A series circuit is a circuit where all the components are in one big loop.

In the figure on the left, the two light bulbs are in series, this is becuase they are next to each other. We can see this using a graphical drawing and circuit diagram.

Series circuits have three specific properties:

1. The components cannot be controlled individually.

   • This is because the circuit is only one loop, there is no other part to be controlled

2. If one component breaks the whole circuit breaks.

   • A component breaking will stop the flow of electrons through the entire circuit.

3. The voltage divided amoung the components.

   • This is because the voltage (electrical pressure) is absorbed into each device that uses it.

Parallel Circuits

A parallel circuit is a circuit where components can be built on differnt loops.

In the figure on the right, the two light bulbs are in parallel, this is becuase they each have their own loop and effectively have their own direct connection to the battery. We can see this using a graphical drawing and circuit diagram.

Series circuits have three specific properties:

1. The components can be controlled individually.

   • If you put a switch right before each component you could control it without affecting the other loop.

2. If one component breaks the rest of the circuit can still work.

   • A component breaking will stop the flow of electrons only for the loop it is connected to.

3. The voltage does not change for the components.

   • This is because the voltage (electrical pressure) is on two different tracks.

Combination Circuits

We can have circuits the contain both series and parallel parts.

They will gain the properties of both types of circuits at the same time.

In the figure on the left, bulb 1 is in series with bulb 2 and 3 while bulb 2 and 3 are in parallel with each other. 

In the figure on the left, with 3 volts going through the circuit everything in series will recieve 1.5 volts, everything in parallel recieves the same amount of volts. So Bulb 1, 2 and 3 will all have 1.5 volts.

In the second diagram below, the 6 volts of voltage will be given to parallel components meaning 6 volts. Then the series componenets will split their voltage, giving them 3 volts each. So in this diagram I has 3V, II has 3V and III has 6V. 

Activities

Drawing Circuits Worksheet

We will now try to draw some circuits using graphic diagrams and descriptions.