Electric supply unit for plasma installations

What is described here is a power supply unit for plasma systems such as plasma processing or coating devices, wherein electric arcs or disruptive breakdown may occur, which originate from an electrode in particular, comprisinga d.c. voltage or direct-current source whose output terminals are connected via an inductive resistor and a power switch to the electrodes of the plasma system, and possiblya circuit for detecting electric arcs or disruptive breakdown, that operates the switch upon occurrence of an electric arc or disruptive breakdown, in such a way that electrical energy producing a plasma will no longer be applied to the electrodes.The invention is characterised by the provisions that the inductive resistor(s) is (are) each connected to a recovery diode and that the switch is a series switch.In another embodiment of the invention a controller or closed-loop controller, respectively, is provided which, upon occurrence of an electric arc or disruptive breakdown, respectively, extinguishes same by disconnecting the voltage applied to the electrodes or by commutation to an inverted voltage for a defined period of time (deactivation interval), and which, upon occurrence of at least one electric arc or disruptive breakdown event, reduces the activation interval of the voltage causing plasma operation.