Gas discharge device having thermionic electrodes energized by transistor oscillator

Claim 1

AN ELECTRIC SUPPLY CIRCUIT COMPRISING A GAS DISCHARGE TUBE HAVING A PAIR OF SPACED THERMIONIC ELECTRODES DEFINING A DISCHARGE PATH THEREBETWEEN, A D.C.-A.C. IN VERTER COMPRISING AT LEAST ONE CONTROLLED SEMICONDUCTOR ELEMENT, A FIRST CAPACITOR CONNECTED IN SERIES WITH SAID TUBE ELECTRODES AND ACROSS THE TUBE DISCHARGE PATH SO AS TO COMPLETE THE HEATING CIRCUIT OF SAID ELECTRODES, A RESONANT CIRCUIT COUPLING THE OUTPUT OF SAID INVERTER TO SAID TUBE ELECTRODES SO THAT SAID FIRST CAPACITOR FORMS A PART OF SAID RESONANT CIRCUIT, A PAIR OF OTHER CAPACITORS EACH HAVING A VALUE OF CAPACITANCE THAT IS HIGHER THAN THE CAPACITANCE OF SAID FIRST CAPACITOR, AND MEANS FOR CONNECTING EACH OF SAID OTHER CAPACITORS IN SHUNT WITH AN INDIVIDUAL ONE OF SAID TUBE ELECTRODES, EACH OF SAID OTHER CAPACITORS BEING CHOSEN TO HAVE AN IMPEDANCE AT THE OPERATING FREQUENCY OF SAID INVERTER THAT IS SUBSTANTIALLY HIGHER THAN THE IMPEDANCE OF THE THERMIONIC ELECTRODE IN PARALLEL THEREWITH.