NYT obit November 8: Sidney Darlington, a Bell Labs mathematician who pioneered the design of electronic circuits and whose formulas helped launch rockets 300 times without error, died on Oct. 31 at his home in Exeter, N.H. He was 91. At Bell Labs, in Murray Hill, N.J., where he headed the mathematics research center, Dr. Darlington was ranked alongside his colleague Claude Shannon for breakthroughs in communications networks that foreshadowed the integrated circuit and in turn computers and modern communications. Dr. Darlington's discovery of ways to custom-design circuits using precise mathematical specifications, a speciality now called network synthesis theory, made him a leading authority in electronic cirsuits for decades, said Dr. Ernest Kuh, a former colleague who is now at the University of California at Berkeley. Before Dr. Darlington's work, circuits were designed in an intuitive, ad hoc manner. His advances won him the highest award in his field, the Medal of Honor of the Institute of Electrical and Electronic Engineers. At a chalkborad at Bell labs with three or four other rocket guidance experts, he would scrawl equations that became the basis for guiding the Air Force Titan I, the Thor-Delta and dozens of other rockets. His rocket guidance formulas could instantly plug in the information from several sources -- the trajectory designed to launch a staellite, the data from radar that tracked the rocket, and the instruments in the rocket itself -- and could then return a flow of commands to the rocket. Always a tinkerer, Dr. Darlington in the 1950's spent a weekend at home playing with a new gadget, the transistor. Trying to get more gain from an amplifier the size of a kernel of corn, he found a way to combine two or more transistors in one chip, an idea that became the Darlington Compound Chip and pointed the way toward integrated circuits. ----- For more see NYT online: http://www.nytimes.com