plugs you can buy with a transformer attached to them. They
plug directly into the wall socket and often feed power
down a thin cable into something like a walkman or portable
they don't seem to have a replaceable fuse in them so how
do they work?
with transformers are that consumers are not allowed to tamper
with their fuses so they are all sealed inside the device.
There are two ways which the transformers protect themselves.
Firstly they have a thermal fuse in the primary coil which
blows when the current rises above 2 amps or the temperature
rises above 130 degrees.
are both extreme conditions which shouldn't occur during
the lifetime of the device. The second fuse device is called
a PTC. Which is a kind of bi-metallic strip which bends
away breaking the contact when the temperature gets to high
. As it cools down again it bends back restoring the circuit.