Power supply for an x-ray emitter, x-ray device and method for testing an x-ray device

A power supply for an x-ray emitter is disclosed. A voltage source of the power supply is configured to provide an acceleration voltage or a heating voltage between a first internal contact and a second internal contact to, in a first operating mode, supply the x-ray emitter with power. The power supply includes a control device configured, in a second operating mode, to detect a voltage between the first and the second internal contact and/or to detect a current via the first and/or second internal contact. As a function of the detected voltage and/or of the detected current, the control device is configured to activate a warning device for giving a warning and/or to transmit a warning signal. A method is further disclosed.