Electromagnetic Interference in High Frequency Transformers

One major challenge in designing high frequency transformers is reducing electromagnetic interference (EMI). The main sources of EMI are the suction force between magnetic cores and the repulsive force between winding wires. Both of these forces operate at the same frequency as the transformer itself.

 For a high frequency switching transformer running at around 100kHz, the vibration does not overlap with the human audible range below 20kHz, which prevents unwanted audio noise. However, EMI can still affect sensitive circuits. To mitigate this, designers use optimized winding structures, shielding, and improved core materials. In many designs, a high frequency isolation transformer is preferred because it ensures both effective isolation and minimized interference.