This is a typical circuit for an old microwave oven. We took it from an August 1973 Radio Electronics magazine, from an article that taught how to make repairs.
The oscillator shown in the figure generates a rectangular signal with a 50% active cycle (square)...
This power supply can be implemented with a TIP32 providing an adjustable output at the 2k2...
This switched circuit was found in an old documentation and no information about the transformer...