a supplementary device , such as a charging , cleaning and / or diagnosis device , for a small electric device , such as an electric hair cutting or hair removal apparatus or an electric toothbrush , but particularly for an electric shaving apparatus , includes an arrangement to detect whether it is connected electrically and / or magnetically to the small electric device , and an arrangement to discriminate between different types of small electric device . this arrangement monitors an electric and / or magnetic quantity prevailing at the connection of the supplementary device . a method for detecting the presence of an electric and / or magnetic connection between said devices includes monitoring an electric and / or magnetic quantity prevailing at the connection of the supplementary device .