1. W Richards The Weald School
12/05/2019
Electrical Circuits
W Richards
The Weald School

2. Drawing Circuits 1) A cell, a bulb and a switch “in series”
12/05/2019
1) A cell, a bulb and a switch “in series”
2) A battery of cells, a switch and two bulbs in series

3. Measuring electric current
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We can measure the amount of electric current flowing through a circuit using a device called an “ammeter”. A

4. Current in a series circuit
12/05/2019
If the current here is 2 amps…
The current here will be…
The current here will be…
And the current here will be…
In other words, the current in a series circuit is THE SAME at any point

5. Changing the current
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If a battery is added the current will ________ because there is a greater _____ on the electrons
If a bulb is added the current will _______ because there is greater ________ in the circuit

6. Parallel circuits
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A parallel circuit is one where the current has a “choice of routes”:

7. Current in a parallel circuit
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A PARALLEL circuit is one where the current has a “choice of routes”
Here comes the current…
Half of the current will go down here (assuming the bulbs are the same)…
And the rest will go down here…

8. Current in a parallel circuit
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If the current here is 6 amps
And the current here will be…
The current here will be…
The current here will be…
The current here will be…

9. Advantages of parallel circuits…
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There are two main reasons why parallel circuits are used more commonly than series circuits:
Extra appliances (like bulbs) can be added without affecting the output of the others
If one appliance breaks it won’t affect the others either

10. Words – large, harm, safety, melt, live, circuit, fuse
Fuses
12/05/2019
Fuses are _______ devices. If there is a fault in an appliance which causes the ____ and neutral (or earth) wire to cross then a ______ current will flow through the _____ and cause it to _____. This will break the _______ and protect the appliance and user from further _____.
Words – large, harm, safety, melt, live, circuit, fuse