Why does the adapter that came with my device list a higher voltage than the batteries in the device?

Question

I have a scanner with a 6V battery inside yet the adapter that came with it has a 12V output - I also have a shaver that says 2.4 volts on the back of it, but the adapter says it's output is 5.3V. Why is this?

Answer 1

There is a voltage overhead involved when there is a voltage regulator in a device. About as low as the overhead goes is about 0.7V. Average is about 1-2 V so if you have a 6V device then it's unlikely the supply voltage will be less than 8V and more likely 12V as they are by far and aways the most common AC adaptor.