1. P5 Science/ Electricity/HBL T3W1 2009/danielle
Electricity (Uses, closed and open circuits, bulbs in parallel and series arrangements)
Images from:
P5 Science/ Electricity/HBL T3W1 2009/danielle

2. Day 2: What are some uses of electricity?
Some items in our homes are mains- powered while some are battery- powered.
Mains- powered means they have to be connected to a power socket.
For example, the iron, the television
Battery- powered means batteries are enough to power them.
For example, handphones, IPods
P5 Science/ Electricity/HBL T3W1 2009/danielle

3. What are closed and open circuits?
A simple electrical circuit is made up of the following:
 power source
(batteries or connection to power sockets)
 light bulb or light bulbs
 wires
 switch or switches (some circuits might not have switches)

4. What are closed and open circuits?
A closed circuit is a circuit which electricity can flow from the power source to the electrical appliance that needs to be powered.
Note that there are no gaps in a closed circuit.

5. What are closed and open circuits?
An open circuit is a circuit which electricity cannot flow from the power source to the electrical appliance.
Note that there is a gap in an open circuit.
gap

6. Day 3: Symbols of a circuit diagram
You have seen two electrical circuits in the previous slides
But it would be hard to draw pictures of a bulb and the batteries.
So, we usually use symbols to represent the bulbs and batteries and even switches.

7. Symbols of a circuit diagram
The different symbols we use for a basic circuit diagram are as below:
 bulb :
 battery:
 wire:
 switch:

8. Simple circuit diagrams
A simple closed circuit diagram would look like this:
Note that there are no gaps in the circuits
Look at how the wires are drawn straight
Circuit drawn with pictures
Circuit drawn with symbols

9. Simple circuit diagrams
A simple open circuit diagram would look like this:
Note that there is a gap in the open circuit.
Look at how the wires are drawn straight
gap
gap

10. Day 5: Bulbs arranged in Series and Parallel
Bulbs can be arranged in Series or Parallel.
The way the bulbs are arranged will affect the brightness of the bulbs.

11. Bulbs arranged in Series and Parallel
This is an example of a circuit diagram with bulbs arranged in parallel:
If the battery has a voltage of 1.5V, then each of these 3 bulbs will get a voltage of 1.5V.
1.5V

12. Bulbs arranged in Series and Parallel
To draw an electrical circuit with bulbs arranged in parallel, it will be like this:
Each of the bulb has its own path of electricity. Therefore the amount of electricity is the same for every bulb.
1.5V
1.5V
1.5V

13. Bulbs arranged in Series and Parallel
What are the advantages of having a circuit with bulbs in a parallel arrangement?
When one of the bulbs, fuses, the current will just simply flow to the other bulb. The other bulb will still light up because it has a separate path.
Bulb still lights up
Bulb fused

14. Bulbs arranged in Series and Parallel
An electrical circuit with bulbs arranged in series will look like this:
If the battery has a voltage of 1.5V, then this is shared among the three bulbs.
1.5V

15. Bulbs arranged in Series and Parallel
To draw an electrical circuit with bulbs arranged in series, it will be like this:

16. Bulbs arranged in Series and Parallel
In a series arrangement, the current will flow through the bulbs, one after another.
Therefore, if one of the bulbs fuses, the circuit will become an open circuit.
The other bulbs will not light up.
Bulb no longer lights up
Bulb fused