Reviewing the computer adapter product, a certain model of product was subjected to a current of 22V to 5V and a current of 6A. The temperature was too high, the efficiency was low, and the temperature rise reached 100 ℃. After the company calculated and selected the specifications of the magnetic ring and copper wire to make a ring coil assembly test, which significantly reduced the temperature rise. This case review satisfied the customer and provided more opportunities to cooperate with Mingci Electronics. The engineering and technical strength was also recognized. The customized coil business also took Mingci Electronics another step forward.