Dr. Alexander Ellett, 87, a scientist, former educator and retired executive of the Zenith Corporation who received the President's Medal of Merit in 1948 for his work on ordnance development during World War II, died of congestive heart failure Nov. 26 at his home in Carmel, Calif.

Dr. Ellett was a physicist who specialized in spectroscopy. In 1940, when he was a professor at the University of Iowa, he was detailed to war-related research at the Carnegie Institution here. He organized a group at the National Bureau of Standards, under the National Defense Research Committee of the Office of Scientific Research and Development, where this country's proximity fuses for bombs and rockets were developed. He later worked on guided missile systems.

During World War I, Dr. Ellett served in France as a pilot in the Army Air Service.

He was born in Chillicothe, Mo., earned a bachelor's degree from the University of Colorado and master's and doctor's degrees from Johns Hopkins University.

From 1945 to 1950, he was director of research for Zenith in Chicago. He was vice president for research when he retired in 1963 and moved to California.

Survivors include his wife of 60 years, Onabelle; a daughter, Elizabeth; a son, Charles, and nine grandchildren.