<p>The inverter (26) has a rectifier unit (28) and an inverter unit (32) interconnected via a direct voltage intermediate circuit (30). An intermediate circuit capacitor (46) is provided in the direct voltage intermediate circuit. The intermediate circuit comprises a switching unit (42) with a semiconductor switch, which selectively interrupts electric current flowing from the rectifier unit to an inverter side part (38) of the intermediate circuit. The circuit capacitor is arranged in the side part. The switching unit comprises a mechanical switch for bridging the semiconductor switch. The semiconductor switch comprises a transistor e.g. silicon carbide MOSFET (54) or silicon carbide-junction FET (JFET) or silicon transistor. The switching unit is selected from MOSFET and a JFET. The inverter unit is formed as alternating voltage inverter and direct voltage inverter. The rectifier unit is formed as a boost converter. An independent claim is also included for a method for operating a frequency inverter.</p>
