An electrical device comprises a stack of electric elements, each comprising: an electrically insulating substrate, for instance of plastic, and at least one electrically conductive track connected to said substrate; the end zones of each of which tracks have terminals either for connection to a source of electrical energy, whereby electric current is conducted through each track during operation, or connection to a device for taking off electric current generated by magnetic induction in the track; which electric elements are connected mechanically to each other such that the device is unitary.