What is the history of electrical outlet changes?
That is one simple question that can't have any simple answers! For a start, do you mean "the history of electrical outlet changes" just for one country (such as USA or England, or Australia, or ...) or do you mean worldwide? One way for you to get some answers to this question would be to go to a science museum and ask if there is a section dealing with the history and development of electricity supply systems. Or you could go to your local library and ask one of the staff there to suggest some books for you to read that cover this subject!
The definition of an outlet in Article 100 of the National Electrical Code book (US) is: "Outlet. A point on the wiring system at which current is taken to supply utilization equipment." You can have a receptacle outlet, lighting outlet, or some other hardwired equipment outlet. <<>> The definition of an outlet in Section 0 (Object, Scope and Definitions) of the Canadian Electrical Code book is: "Outlet. A point in the wiring installation at which…
A 120 V outlet is the standard residential and commercial electrical outlet for North America. When additional electrical power is needed, other outlet options are available, but typically, one or more duplex (meaning double, or two outlets) receptacle is installed in every residential and commercial room.
There is an adapter for this purpose. It screws in to socket as a typical light bulb, and has a outlet on the opposite end. These however are not recommended. An electrical outlet should be rated for 15 amps. A bulb outlet is not rated for this much current and could be a fire hazard. Also this type of an adapter lacks a ground connection point.