It is very important that electrical devices in homes, cars, aeroplanes and other complex machines are protected from higher voltage than the wires are designed to take — otherwise, the devices can break and even catch fire.
In real life electrical circuits, it is possible that wires (conductors) loose their insulation and come into contact with the ground or other conductors. If that happens, the voltage in the wire will have no resistor (load) and the same high voltage will be returned to the source of power.
This can result in overheating, as there is way too much voltage than the wires can take. Overheating will then cause melting and eventually a break (open) in the circuit.
One way to protect a circuit is to add a fuse, circuit breaker or thermal breaker to the circuit.
These work in similar ways, but let us consider a fuse in more detail:
fuse is simply a strip of alloy wire (made of bismuth and tin), which is connected to the circuit. The fuse is usually designed to take specific volumes of electricity (voltage). For example is a 3amp fuse is fixed into a circuit — it cannot take any more than 3amps of electricity. If for any reason, there is a surge or increase in the voltage, the fuse will melt immediately and break. This will stop the flow of high voltage and prevent any potential damage to the circuit or device.
Our readings and research for this lesson included the following resources