Magnetic Circuit of Flyback Transformers and Relevant Measurements

The magnetic circuit of flyback transformers of television receivers is analyzed. Formulas for the number of turns of primary coil and the thickness of the air gap are derived. Then the requirements on the U-cores are discussed. Various measurements may be made with a simple line output circuit. The waveform of the current in the primary coil may be observed and equivalent inductance of the coil calculated so that the thickness of the air gap may be determined experimentally to check with the calculated results. The dynamic B-H curve is a part of the hysteresis loop and examples are given. Formulas for the magnetic loss and the principle of measurement on this circuit are then discussed.