Self-excitation push-pull type converter

A self-excitation push-pull converter, comprising a first transistor and a second transistor, each with an emitter and a collector where the emitter of the first transistor is connected to the emitter of the second transistor, and a transformer with a magnetic core and two primary side coils each having a first end and a second end, wherein the first ends of the two primary side coils are connected to each other to form a voltage input and the second ends of the two primary side coils are connected to the collector of the first transistor and the collector of the second transistor, respectively, and the magnetic core has a closed magnetic path and comprises a main section and at least one partial section, said partial section reaching magnetic saturation before said main section when excited under a same increasing magnetic field,

• wherein said partial section has a sectional area of a size less than 80% and greater than 4% of a sectional area of said main section,
• wherein a length of said partial section is negatively correlated to a ratio of the sectional area of said main section to the sectional area of said partial section.