The first widely applied electric light source was the arc-lamp, the development of which the Ganz factory also took part in. Its working principle was the arc light discovered in early 1800s. Arc lamps became widely used in the 20th century, especially in public lighting (it was most efficient in open areas or large halls). Its improved version is used even today in film studios and for projectors.

One of the pictures shows the internal mechanism of the “EH 150” arc lamp of the Ganz factory, while the other picture shows the alternating current arc lamp of the same company from 1908.