Abstract: The Circular transformer-generator is a rotational electrical machine that joins creation of sinusoidal voltage and current with the transformation phenomenon or mutual inductivity of the individually wound stator coils. The Circular transformer-generator consists of the stator part that has a number of the inner pole extensions, and a number of the outer pole extensions with spaces between them for the individual stator windings, and of the double rotor assembly that contains the inner body and the outer body with the magnetic or electromagnetic poles that during rotor rotation supply induction to the stator assembly or the individual axially wound stator coils. The axially wound coils of the stator are connected to the Circular transformer-generator output, and at the same time are tied (act upon each other) by their mutual induction, during which time also the transformation coil ratio can be utilized.