Patent drawing - 454622 - . Public domain image

U.S. Patent 0,454,622 - System of Electric Lighting - 1891 June 23 - Apparatus devised for the purpose of converting and supplying electrical energy in a form suited for the production of certain novel electrical phenomena, which require currents of higher frequency and potential. It specifies an energy storage capacitor and discharger mechanism on the primary side of a radio-frequency transformer. This is the first-ever disclosure of a practical RF power supply capable of exciting an antenna to emit powerful electromagnetic radiation.