The Turn Of The Century Electrotherapy Museum http://www.electrotherapymuseum.com Low voltage DC Tesla Coil:  Powered by Relay 11. Jan 2009 This can be done to some extent with any relay or contactor with normally closed (NC) contacts. The relay is wired to turn itself on and off continuous.  An electromagnet is placed in parallel with the relay.  The self-induction of the electromagnet when the circuit is broken is used to charge a condenser to high voltage and discharge it through a Tesla Coil...the result is a 110VDC powered Tesla Coil.