Acer, eMachines, and Gateway are all the same company.
Essential to the purchase of your new laptop Adapter is the part number. A part number is a unique identifier that is assigned to a part to simplify referencing and to unambiguously define a part within a single manufacturer. Ac adapters of the same part number may have different connector sizes, so don't buy a AC ADAPTER based on the part number of the AC adapter unless you are sure of the connector size of the AC ADAPTER. .