VELLEMAN PS1505ACU NON-REGULATED SINGLE-VOLTAGE ADAPTER AC INPUT AC OUTPUT 15VAC/500mA. Our line of AC to AC power adapters are "step down" transformers. Unlike traditional AC-DC power adapters which convert AC current to DC current, our AC-AC adapters lower (or step down) the voltage from 110/120 volts to the 9, 12, 15 or 18 volts depending on the model. Please note, these are unregulated power supplies. Prior to purchasing this unit, you need to determine if your device requires a regulated power supply.