Inverter arrangement employing resonant capacitive elements directly connected across the switching elements for zero voltage switching

A circuit arrangement for operating a high-pressure discharge lamp, comprising:

• input terminals for connection to a supply source,
• output terminals for connection of the lamp to be operated,
• a ballast coil for stabilizing the current through the lamp, wherein the output terminals and the ballast coil form part of a full-bridge commutator network and further including a rectifier coupled between the input terminals and the commutator network and four switches each of which is connected in parallel with an associated capacitor, each capacitor forming a tuned circuit with the ballast coil such that switching of each switch takes place when the voltage across the switch is substantially zero and wherein the commutating frequency has a commutating cycle in which about 15% or less of the commutation cycle elapses between the first of the four switches to be turned off and the last of the four swithes to be turned on.