check your laptop's power brick -- if it mentions both 230V/50Hz (europe) and 115V/60Hz (US), then it's safe to plug into a US outlet with just the pin-changer. Most laptop powersupplies are universal these days, and will work without problems.
If the device does NOT mention 110-115V specifically, then you probably need to get a more expensive power converter that does the switching for you.
(Some 'dumb' devices like shavers and such might physically work, but either run at half speed at double speed depending on the voltage they receive... Neither of which is desirable, of course)
If the device does NOT mention 110-115V specifically, then you probably need to get a more expensive power converter that does the switching for you.
(Some 'dumb' devices like shavers and such might physically work, but either run at half speed at double speed depending on the voltage they receive... Neither of which is desirable, of course)