John Bardeen, 82, the last of the three surviving physicists who developed the transistor and a two-time Nobel Prize winner, died of a heart attack yesterday at Brigham and Women's Hospital in Boston. A professor emeritus at the University of Illinois, he was in Boston for medical consultation and diagnosis when stricken.

A theoretical physicist, Dr. Bardeen shared the 1956 Nobel Prize with William P. Shockley and Walter H. Brattain for their 1948 development of the transistor, a device that revolutionized the electronics industry and became the basic element in products ranging from missiles to telephones and computers.

He was awarded his second Nobel Prize in 1972 for research on superconductivity, with graduate students Leon Cooper, now of Brown University, and J. Robert Schrieffer, now of the University of California at Santa Barbara. They developed a theory of low-temperature superconductivity in which electricity travels through matter with little or no resistance, without losing energy. This led to such practical uses as magnetic imaging techniques for medical diagnoses.

Dr. Bardeen's work that led to development of the transistor began in 1945, when he joined a newly formed research group in solid state physics at the Bell Telephone Laboratories in Murray Hill, N.J. Development there of the transistor -- the word is a combination of transfer and resistor -- became one of the major electronic milestones of the century.

"The transistor made the information age possible," said Larry Smarr, director of the Center for Supercomputing Applications at the University of Illinois.

Essentially an electrical valve that can be used to control the flow of electricity and amplify or switch electrical signals, the transistor made possible the development of virtually every modern electronic device. It was more efficient and 50 times smaller than the vacuum tube it replaced in such products as radios and television sets and electronic devices.

In 1951, Dr. Bardeen left Bell Laboratories for the University of Illinois, where he helped to establish research programs on experimental and theoretical aspects of semiconductors.

He once said that he considered his superconductivity theory the greatest of his scientific achievements, although economically it has been dwarfed by the development of the transistor. CAT scans, a method for diagnosing soft tissue disorders, especially of the brain, through a computerized combination of tomograms from images, are among the practical applications of Dr. Bardeen's superconductivity theory. Other applications, such as levitation of high-speed trains, have yet to progress beyond the theoretical stage.

A native of Madison, Wis., Dr. Bardeen graduated from the University of Wisconsin, then spent three years doing research in geophysics at Gulf Research Laboratories in Pittsburgh. He received a doctorate in physics from Princeton, then spent three years at Harvard and three more at the University of Minnesota.

He was at the Naval Ordnance Laboratory in Washington from 1941 to 1945, then joined Bell Laboratories after World War II. He was an active professor at the University of Illinois from 1951 to 1975, then became professor emeritus.

In 1990, Dr. Bardeen was one 11 recipients of the Third Century Award presented by President Bush to honor exceptional contributions to American society. He received a gold medal from the Soviet Academy of Sciences in 1988. Life magazine last September included him on its list of the 100 most influential Americans of this century.

The Sony Corp., whose multibillion-dollar business is based in large measure on the development of the transistor, last year endowed a $53 million John Bardeen professorial chair at the University of Illinois. "The transistor ignited modern technology," said Makoto Kikuchi, a former director of Sony Research Laboratories.

Dr. Bardeen's survivors include his wife, Jane Bardeen; three children, James M. Bardeen of Seattle, William A. Bardeen of Glen Ellyn, Ill., and Elizabeth A. Greytak of Chestnut Hill, Mass.; and six grandchildren.

AARON POSNER

Plastering Contractor

Aaron Posner, 89, a retired plastering contractor, died of respiratory ailments Jan. 29 at the Hebrew Home of Greater Washington.

Mr. Posner, who lived in Silver Spring, was born in Russia. He immigrated to New York at the age of 7 and worked as a plasterer there before World War II. He worked in a variety of war-related industries in Virginia during the war, then settled in the Washington area after the war.

He founded Alpo Plastering, which specialized in commercial construction plastering and drywall, and was subcontractor at several major commercial construction projects in the Washington area. He retired in the mid-1960s.

He was a member of Samuel Gompers Masonic Lodge in Washington.

Survivors include his wife of 60 years, Claire Posner of Silver Spring; a son, William Posner of Rockville; six grandchildren; and a great-grandchild.