It is my understanding that the a laptop charger's "brick" is designed to convert a large range of AC sources to the DC that the laptop needs. That is why the bundle the same "brick" with all laptops, but just change the cord that goes from the "brick" to the outlet depending on what market the laptop is sold in. That is why you do not need a transformer when you travel int'l...just a plug adaptor.

I've seen flight attendants charging their phones in the various "vacuum outlets" on different planes/airlines...