The tesla coil was patented in 1891 and allowed him to send
energy through vacuum tubes by wireless transmission.
The ability to have wireless energy greatly aided in the work
of electric-magnetic fields while also paving the path for
wireless communication (radio), x-ray, and improvements in AC
generators.
A tesla coil is a high frequency
alternating-current transformer that amplifies
the current and voltage. The Tesla High Frequency Coil
consists of four
main parts: The step-up transformer (high voltage
transformer/induction
transformer), the interrupter (spark gap), the condenser (high
voltage
capacitor), and the oscillation transformer (combination of
primary coil and
capacitor) [Haller & Cunningham]. The step-up
transformer is an
induction coil that is connected to the source of power (the
AC mains) and it
is used to charge the condenser until it is fully charged. The condenser
gathers
the
electricity until
it has reached its highest charge capacity.
At this point, the interrupter, which has been acting
to provide a path
of high resistance until the condenser is at its full capacity
(not allowing
electricity to flow), instead collapse and connects the
primary circuit.
This discharges the condenser and returns the interrupter back
to a path of
high resistance. The electricity in the primary circuit
during the
collapse of the interrupter creates an electric-magnetic
field, the energy
stored within the secondary coil used as an inductor.
The action of the
interrupter collapsing and returning back to high resistance
has a certain
period, resulting in a certain frequency of electricity.
Since
alternating-current mains constantly apply electricity to the
condenser, the
condenser acts on the system similarly as a driven oscillation
where a
resonance can be reached. At this resonance, the voltage
and current are
greatly amplified.