Ruhmkorff coil, by ferdinand ernecke, berlin.
Ruhmkorff coil. A type of electrical transformer used to produce high-voltage pulses from a low-voltage direct current (dc) supply. The induction coil was the first type of transformer. Its development started in 1836 by nicholas callan and others. Heinrich daniel ruhmkorff (1803-1877) however made the first succesfull apparatus of this type in 1851. Signed by ferdinand ernecke, berlin. Measurements 63 x 30 x 48 cm