AC-DC transformer, ... but the C64 also requires 9V AC in addition to DC (weirdly), so I didn't want to mess with transforming AC voltages. ... -5, 9, 12 and 24v rails.

This is the same idea of converting DC to AC so it can go through a transformer. But the conversion is done with a relay-like device. Uses. In addition to old radios, ...

The problem of transformer core saturation can lead to the failure of bridge and push-pull topologies. ... (V in) is connected to DC-AC inverter, control circuit operates to close switch S1, ...