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Student 2: High Merit
AS 90941
Student 2
From my results I noticed that: Voltage being received by the resisters in the circuits was the
same as the total voltage supplied. This is typical of parallel circuits even though current
increases across the parallel branches. The energy carried by the electrons is the same.
Current, unlike voltage raised between circuits. The current drawn by a resistor depends on
its resistance (Ohms Law states that resistance is inversely proportional to current) Low
resistance has high current and vice versa. The order of circuits has no effect on the results.
Ohms law states that the heat in wires is directly proportional to the current flowing. More
current hotter wires. If current is very high insulation can melt and start a fire.
Application of results to a house hold environment:
In a house circuits are wired in parallel so as all branches of a circuit get 240V. It also means
a single branch can operate independent of the other branches. All components get the max
voltage. In NZ this is 240V. The problem comes with current. In parallel circuits as more
appliances are added to a circuit then more current flows and more current means a hotter
environment. If enough appliances are added to a parallel circuit then the wires get hot
enough to melt the insulation then start a fire. (1) To stop this we add circuit breakers to the
circuit at the start and this circuit breaker is wired in series. If too much current flows then the
circuit breaker trips taking out all the parallel circuits until the problem is fixed. (2)
The use of multiboxes today compounds this issue so the safest multiboxes are those with
inbuilt circuit breakers. They stop people overloading the multiboxes.