The Zooka uses 5V DC to charge and operate. Some sort of transformer needs to convert the wall voltage to the 5 volts. In the case of a computer, the USB ports provide that 5 volts DC. In the case of a USB/AC charger, it would have to be either made for 220 volts AC or be plugged into a travel adapter that cuts one leg of the 220 volts off and provides 110 volts to your North American USB/AC adapter.