The Challenge: Make a Transmitter and Receiver 
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How can we make
a spark transmitter?
To create a spark
you need a large voltage difference: the bigger the voltage difference,
the bigger the spark. The bigger the spark, the more radio waves are created.
And the more radio waves created, the further you can transmit a signal. To
create a voltage difference we need a supply
of electricity, and on the island we made use of a car battery. The battery
produces a voltage difference of 12V, which is not really enough for what
we want. To increase the voltage we made a transformer.
How does a transformer
work?
A transformer is
a device that can increase or decrease voltage and it does this by decreasing
or increasing the corresponding current. We can understand this best by
considering the power through the system. The power is given by the voltage
x current. The power in and out of the transformer must be the same (ignoring
heat losses) it's just that the transformer converts one set of voltage
x current to another set of voltage x current.
For example, 1 Volt
x 6 Amp = 6 Watts. This is the same as 6 Volt x 1 Amp = 6 Watts.
The transformer can
convert 1 Volt to 6 Volt (a multiplication of 6) if the corresponding
current is converted from say 6 to 1 Amp (a multiplication of 1/6^{th}).
How is a transformer made?
