Inductorium- Ruhmkorff’s coil circa
This apparatus, capable of producing induced currents at high
potentials, consists of a primary coil of wire around a soft iron core.
There is also a make and break device so that the primary current
is interrupted regularly.
A secondary coil is wound on top of the primary with precautions
as to the insulation of the extremely high potential secondary circuit
from that of the low voltage primary.
The high potential output is produced by induction due to the lines of
force of the magnetic field cutting the primary and secondary coils.
Fizeau increased the output e.m.f. by connecting a condenser in the
primary circuit effectively tuning it.
A commutator is normally included to reverse the direction of the
Another form of current breaker is Wehnelt’s electrolytic interruptor
consisting of a platinum anode and a lead cathode dipping in sulphuric
Heinrich Daniel Ruhmkorff 1803 to 1877 (Portrait circa 1850).