VELLEMAN PS1810ACU NON-REGULATED SINGLE-VOLTAGE ADAPTER - AC INPUT AC OUTPUT - 18 VAC / 1000 mA . 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 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.