Electric describes things that use electricity to make them work: an electric iron/shaver/guitar
Electrical is used in more technical contexts when referring to the manufacture or use of electricity: an electrical fault ♦ electrical wiring ♦ an electrical engineer
Electrical is also used with general nouns when referring to things that are powered by electricity: electrical equipment ♦ an electrical appliance
Electronic describes equipment and systems that use computer chips, transistors, and similar very small parts: The store sells computers, MP3 players, and other electronic products. ♦ an electronic surveillance system.