Energising Coils with a Polyswitch

Despite the fact that fuses have had almost exclusive reign during much of the previous century, the impact made by resetable fuses such as the Polyswitch series from Raychem over the last decade is clearly noticeable. The resistance of these components (which have a positive temperature coefficient) increases suddenly when the temperature is raised. They may be used as a replacement for a fuse, with the convenience that it is no longer necessary to replace this fuse once it has done its job.