How do I calculate the source impedance of a MOSFET inverter. The inverter uses four IRFP460 MOSFETs in parallel. These MOSFETs have a drain to source on-resistance of 0.27Ω. The MOSFETs are in parallel so they will have a total resistance of 67.5 miliohms. Would this be the source impedance? The output is an LCLR tank circuit. How would I calculate the load impedance of this output circuit.