Abstract: A method of operating an x-ray unit that supplies the maximum power at all times, for which the supply or input voltage at the x-ray tube must be half the power supply voltage ((Vbat)/2 or (Vline)/2), which will be termed the reference voltage (Vref). In case of a deviation from the reference voltage, the method modifies the current supplied, changing the exposure time so that the maximum power is delivered at all times. In short, it is based on a method that regulates the tube current as a function of the supply voltage (of the batteries or the grid).