Moritz Hermann von Jacobi (German: [ˈmoːʁɪts fɔn jaˈkoːki]; 21 September 1801 – 10 March 1874), also known as Boris Semyonovich Yakobi (Russian: Борис Семёнович Якоби), was a German-Russian electrical engineer and physicist.

Jacobi tested the output of motors by determining the amount of zinc consumed by the battery.

With the financial assistance of Tsar Nicholas I, in 1839 Jacobi constructed a 28-foot electric motor boat powered by battery cells, which carried 14 passengers on the Neva river against the current at three miles per hour.

In 1842-1845 he built a telegraph line between Saint Petersburg and Tsarskoe Selo using an underground cable.

The mine was tied to the sea bottom by an anchor, a cable connected it to a galvanic cell which powered it from the shore.