Just as a quick guide, I believe that “electric” as an adjective refers mostly to the physical phenomenon, hence “electric field,” “electric power” etc. In contrast, the adjective “electrical” refers to the practical application of electricity and electronics to the real world, so we say “electrical engineering” and such. It is the National Electrical Code (NEC) not the “electric code.” You are an electrical engineer, right? Not an electric engineer.
On this basis, we should use the latter “electrical” for all of the examples you provide.
Best,
Alan Siegrist
Orinda, CA, USA
Well, in deciding between two alternative wordings, googlefight.com allows you stage a "google fight" between the two alternatives.
http://www.googlefight.com/electric+circuit-vs-electrical+circuit.php
gives "electric circuit" the edge, with a "Google visibility" score of 100, as compared to 67 for "electrical circuit".
The only formal distinction I know of between an -ic word and its corresponding -ical version is explained at
http://www.quickanddirtytips.com/education/grammar/historic-versus-historical
Bottom line: Use whichever version sounds more familiar to you
(if you're a native speaker, you have an advantage). Just go
ahead with whichever sounds better to you, and worry no further
about it.
-- Mark Spahn (West Seneca, NY)
The site mentioned in David Littleboy’s post reminded me of an exception to this rule. This is the exception that the adjective “electric” has another specific use, namely that of distinguishing things that run on electricity from those that run on other power sources, such as “electric vehicles” (not electrical vehicles, as distinguished from gasoline-powered vehicles) and “electric trains” (as opposed to steam trains). So an “electric engineer” would be absurd in this sense since engineers do not run on electricity.
Best,
Alan Siegrist
Orinda, CA, USA