3T Electricity Summary

Electricity
Summary
Welcome!
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This lesson contains 15 slides, with text slides.

time-iconLesson duration is: 45 min

Items in this lesson

Electricity
Summary
Welcome!

Slide 1 - Slide

Plan for today
1. Questions
2. Summary or self study
3. Self study
        - Do the 'test yourself'
        - Study the paragraphs (summary + definitions: p. 60-63)
        - Work on the diagnostic test
        - Work on problems in the book

Slide 2 - Slide

Do you already have some questions?

What parts do you find most difficult?

Slide 3 - Slide

§1 - The power station

Slide 4 - Slide

§1 - Induced voltage

Slide 5 - Slide

§1 - Electrical power
Electrical power is just the energy that something uses per second! So we calculate it with:
P=tE
Special units:
W       -     J       -    s

kW  -  kWh    -      h
1 kWh = 3.600.000 J

Slide 6 - Slide

§2 - The energy grid
!!!
At home: 
U = 230 V

Slide 7 - Slide

§2 - The transformer
Every transformer:



Ideal transformers:
UsUp=NsNp
Pp=Ps

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§2 - Capacity
Every battery has a certain capacity. The capacity tells you how long a battery can deliver a certain current. You can calculate it with:
C=It
Special units:
Ah       -     A       -    h

mAh     -  mA    -    h

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§3 - Voltage & Current
Utot=U1=U2=...=230V
Itot=I1+I2+...

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§3 - Wires & Colours

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§3 - Electrical power
We can find a relation between the electrical power of a device, the current running through that device and the voltage that it is connected to:
P=UI
Multiple devices at home:
Ptot=UItot

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§4 - Dangers of electricity
  • The current through the wires gets too high                                                                 --> Danger of fire!                                                                    Caused by overloading or short-circuiting                                                                                                           
  • Current from a wire can run through your body                                          --> Can be deadly above 1A! (see table 1)                                                        Caused by loose or broken wires 

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§4 - Prevention high current
Fuses
A fuse blows if the current gets too high.
Circuit breakers
Flips and stops current in one group.

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§4 - Prevention getting shocked
Earth leakage circuit breakers
Earthing
Double isolation

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