Examples described herein may include medical devices and electrosurgical generators with resonant isolated transformers to perform filtering and gain functions. An example electrosurgical generator includes a radio frequency (RF) inverter stage configured to receive an input signal and, in response to control feedback signals, to provide an output signal that provides power to a load. The RF inverter stage includes a resonant isolated transformer configured to receive the input signal and to provide gain and filtering adjustments to the input signal to provide the output signal.