The smallest design
Our customer's request was a major challenge for us at the time. At a given volume, a 750 W power factor-corrected output with 50 W generator feedback and five output voltages were to be installed.
We solved the three-dimensional design problem in an old-fashioned way by forming the heat sink like a selenium rectifier and cooling it with two fans. Later results showed that our theory translated nearly perfectly into practice. We have been selling high quantities of the three designs (19-inch, open and for wall cabinets) from 1998 until today.