an x-ray tube and a power supply;

an x-ray tube including a cathode configured to emit electrons towards a target at an anode, the target configured to emit x-rays out of the x-ray tube in response to impinging electrons from the cathode;

the power supply including (a) a voltage multiplier configured to generate a bias voltage for the cathode, (b) an alternating current source (AC source) configured to provide alternating current to the cathode, and (c) an isolation circuit electrically coupled between the AC source and the cathode;

the isolation circuit is configured to (a) isolate the bias voltage at the cathode from a bias voltage at the AC source, and (b) transfer the alternating current from the AC source to the cathode;

the isolation circuit includes multiple planar transformers, including an initial planar transformer and a final planar transformer;

each planar transformer includes (a) a primary trace on a primary circuit board, the primary trace including a spiral shape; (b) a secondary trace on a secondary circuit board, the secondary trace including a spiral shape; and (c) the primary trace is located in close proximity to the secondary trace such that alternating electrical current through the primary trace will induce alternating electrical current through the secondary trace;

the primary trace of each planar transformer, except for the initial planar transformer, is electrically coupled to the secondary trace of a proximal planar transformer, such that alternating electrical current through the primary trace also flows through the secondary trace of the proximal planar transformer;

the AC source is electrically coupled to, and is configured to provide alternating current through, the primary trace of the initial planar transformer; and

the secondary trace of the final planar transformer is electrically coupled to the cathode and is configured to provide alternating current through the cathode.