I purchased a device labelled "AC Adapter" that labels the input to be 110 to 240 VAC, 50/60 Hz, 1.5A max and the output is labelled as 12, 15, 16, 18, or 19 volts, DC, 4.5A max or 20 or 24 volts, DC, 4A max. Physical dimensions of the plastic enclosure: 2 x 4 x 1.5 inches. The unit is surprisingly/very light.
The price of this new unit was 11 USD in a surplus store.
There is a slide switch for output voltage selection. This was purchased as a potential replacement for a power supply to a gaming console that requires 12 VDC, 3.5A. I will glue the switch at 12V to prevent misapplication. Given the range in possible outputs, will this unit be operating inefficiently at this extreme (low) setting?