Power is the backbone of any electronic system and the power supply is what feeds the system. Choosing the right supply can be the critical difference between a device working at optimum levels and one that may deliver inconsistent results. In addition to alternating current (AC) to direct current (DC) power supplies, DC to DC converters are also available. This Application Note addresses only AC to DC power supplies, however, if DC is already available in your system, a DC to DC converter may be the better design choice. Direct current power supplies are either unregulated or regulated. Regulated supplies come in several options including linear, switched and battery-based.