The IEEE, formerly the Institute of Electrical and Electronics Engineers, is a technical professional association of more than 380,000 student and professional members world-wide. Among the organization's activities are publishing more than 100 journals and magazines, conducting over 300 professional conferences, developing technical standards, and creating and maintaining the IEEE Xplore database.
The IET, formerly the Institution of Electrical Engineers (IEE), is an international organization representing more than 150,000 electrical, electronic, manufacturing, and systems engineering professionals and students. Activities of the organization include developing technical and professional standards, accrediting relevant degree courses and programs, awarding scholarships, and creating and maintaining the INSPEC database.
SPIE is an international organization made up of technical professionals and corporate members, and serves the interests of those engaged in research, development, manufacture, management, or sale of optics, photonics, and optoelectronics technology.