SummaryIn the paper, a new compact electrothermal model of the impulse transformer is proposed. This model has a form of a subcircuit dedicated for SPICE and could be used for low power impulse transformers applicable in switch‐mode power supplies used in electronics. It takes into account simultaneously electric, thermal, and magnetic phenomena occurring in the considered device and describe nonidealities of the core and windings. The form of the elaborated model and analytical dependences describing all its components are presented. Correctness of this model is verified experimentally in a wide range of frequency and load resistance for selected constructions of transformers. Satisfactory agreement between the results of computations and measurements is obtained