Transcript Electricity - nvpsp52009

Electricity
(Uses, closed and open circuits, bulbs in parallel and series
arrangements)
Images from:
http://www.bbc.co.uk/schools/ks3bitesize/science/physics/electricity_intro.shtml
http://www.mcpasd.k12.wi.us/kms/bookmarks/circuits/circuit_symbols.html
P5 Science/ Electricity/HBL T3W1 2009/danielle
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
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)
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.
What are closed and open circuits?
- An open circuit is a circuit which electricity
cannot flow from the power source to the
electrical appliance.
gap
- Note that there is a gap in an open circuit.
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.
Symbols of a circuit diagram
- The different symbols we use for a basic circuit
diagram are as below:
 bulb :
 battery:
 wire:
 switch:
Simple circuit diagrams
- A simple closed circuit diagram would look like
this:
Look at how the
wires are drawn
straight
Circuit drawn with
pictures
Circuit drawn with
symbols
- Note that there are no gaps in the circuits
Simple circuit diagrams
- A simple open circuit diagram would look like
this:
Look at how the
wires are drawn
straight
gap
gap
- Note that there is a gap in the open circuit.
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.
Bulbs arranged in Series and Parallel
- This is an example of a circuit diagram with
bulbs arranged in parallel:
1.5V
- If the battery has a voltage of 1.5V, then each
of these 3 bulbs will get a voltage of 1.5V.
Bulbs arranged in Series and Parallel
- To draw an electrical circuit with bulbs arranged
in parallel, it will be like this:
1.5V
1.5V
1.5V
- Each of the bulb has its own path of electricity.
Therefore the amount of electricity is the same
for every bulb.
Bulbs arranged in Series and Parallel
- What are the advantages of having a circuit with
bulbs in a parallel arrangement?
Bulb still lights up
Bulb fused
- 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.
Bulbs arranged in Series and Parallel
- An electrical circuit with bulbs arranged in series
will look like this:
1.5V
- If the battery has a voltage of 1.5V, then this is
shared among the three bulbs.
Bulbs arranged in Series and Parallel
- To draw an electrical circuit with bulbs
arranged in series, it will be like this:
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