An x-ray tube includes a vacuum housing. A cathode and an anode are disposed in the vacuum housing and insulated by at least one insulation element. Upon application of a high voltage, the cathode emits electrons that strike the anode as an electron beam. A voltage arrester device with an insulation path has a field strength that is higher than a field strength at the insulation element. If a voltage flashover occurs, the voltage is discharged via the voltage arrester device.