When electronics was young - part 3

It is remarkable how many discoveries came about by accident (although it should be borne in mind that these ‘accidents’ were normally preceded by much hard work on allied research). One of these happened to the Danish physicist, Hans Christian Oersted (1777–1851). He was applying a potential across a metal wire to measure the current, when he noticed to his amazement that a compass that happened to be near the wire deflected when the voltage was switched on.