C-core mains transformer
The core is assembled with a small air-gap to compensate for any mains DC-unbalance. Estimated power rating 120 VA, which can be increased with good cooling. The 2 x 250V secondaries are internally divided between the two coils. As a result, the transformer can be used with bridge or full wave rectifiers without a problem of asymmetric load. Magnetic stray is extremely small if filament secondaries of the two coils are loaded identically.