Originally Posted by UNITED959
Voltage, current, and frequency doesn't really matter so long as it's between the range of what the laptop's power "brick" is willing to accept.
There are electrical devices other than laptops, and older laptop power adaptors cannot handle a wide range of power settings.
Originally Posted by UNITED959
Bigger issue is plug configuration, and there's a universal connection that accepts just about anything.
I've never seen a single connector that takes both a North American 2/3-prong plug and a European 2/3-prong plug. In places where you can use both, I've seen two separate outlets, but that's about the best that can be done.