The term "power supply" refers to a device which transforms or adapts electrical energy drawn from some source into a form usable by some other device, the conversion of AC utility power into low-voltage DC for use with electronic devices being a common example. "Off-board" types are designed to be fastened in an end application by some method other than direct attachment to a printed circuit board. They are further classified according to major distinguishing characteristics, such as the type of electrical adaptation performed, physical form factor, or a specific application or purpose for which a product is designed.