Abstract: An oscillator (100) for providing an oscillating voltage for a powder spray coating device (200) is specified. With the aim of improving operational safety, the oscillator (100) as claimed in the invention has a first signal generator (10) for generating an intermediate circuit voltage (11), a second signal generator (20) for generating a modulation signal (21) and a modulation signal isolating element (61), connected to the second signal generator (20), while a first voltage monitoring device (60) is also provided, designed for continuously measuring the oscillator voltage (34), comparing it with at least one specified or specifiable oscillator voltage reference value and, if a first comparison criterion is satisfied, outputting a modulation isolating signal (80) to the modulation signal isolating element (61).