The English version was invented in 1829 (with a patent for an improved version filed in 1844) by Sir Charles Wheatstone; the German version was announced in 1834 by Carl Friedrich Uhlig.
The English version was invented in 1829 (with a patent for an improved version) by Sir Charles Wheatstone. This improved version was filed in 1844. The German version was announced in 1834 by Carl Friedrich Uhlig.