(as opposed to electric). Originally, concerned with the movement of electrons in free space, i.e. in vacuum tubes (UK: valves). Then, by extension, concerned with the movement of charges in semiconductors. Now, by extension, concerned with the representation, storage, and transmission of information by electrical means. That is now what distinguishes electronic engineering from electrical engineering, the latter dealing with energy rather than with information. A further distinguishing feature is that electronic engineering mainly deals with low power levels and frequencies of anywhere between zero and microwaves, while electrical engineering tends to focus on low frequency (50–60 Hz) high power (kilowatts to megawatts). Clearly there will be a grey area where the disciplines overlap.