This is a common demagnetiser from China sold all over Ebay. It is rather dangerous to use as it is prone to overheating as the transformer is very overloaded and there are no protection devises, fuses or cut-outs of of any kind. By adding a thermistor (PTC) the unit becomes much safer and the automatic and gradual decay in the magnetic field caused makes successful demagnetising easier too.

In this video, I explain the problem with the original demagnetiser, the way to choose the right PTC and then explore the characteristics of that PTC for a bit, before finally installing it in the demagnetiser.

Videos mentioned are:

Building a powermeter: [ Ссылка ]
Controlling a DPS5005 power supply module: [ Ссылка ]
Building an adapter for a current transformer: [ Ссылка ]

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