But for circuits where weight, volume, or cost are a major concern, a transformer may be omitted in the circuit design in favor of some sort of transformerless power supply. While power supplies ...

This card enables engineers to design ... power rails with hardware-selectable or software-commanded range of voltages. The power rails are 3.3V, 5V, and 12V (main) and 3.3V and +/- 12V (auxiliary).