Dallas ? Nobel laureate Jack Kilby, whose invention of the integrated circuit ushered in the electronics age and made possible the microprocessor, has died after a battle with cancer. He was 81.

Kilby, a Kansas native, died Monday, according to Texas Instruments Inc., where he worked for many years.

Before the integrated circuit, electronic devices relied on bulky and fragile circuitry, including glass vacuum tubes. In the late 1950s, there was considerable interest – especially in the military – in making devices smaller.

Kilby’s fingernail-size integrated circuit, a forerunner of the microchip used in today’s computers, replaced the bulky and unreliable switches and tubes.

It was during his first year working at TI in Dallas in the summer of 1958 that Kilby set out on a course that would forever change how electricity is used to efficiently and reliably power everything from vacuum cleaners to supercomputers. Using borrowed equipment, he built the first integrated circuit in which all the components were fabricated in a single piece of semiconductor material half the size of a paper clip.

“TI was the only company that agreed to let me work on electronic component miniaturization more or less full time, and it turned out to be a great fit,” Kilby wrote in an autobiography for the Nobel Committee in 2000, the year he won the prize for physics.

Today, integrated circuits can be found in all manner of digital devices, from TVs to microwave ovens. Sales of integrated circuits totaled $179 billion in 2004, supporting a global electronics market of more than $1.1 trillion, according to TI.

The contributions of Kilby – who also co-invented the handheld calculator – are hard to overstate, according to technology experts.

“In my opinion, there are only a handful of people whose works have truly transformed the world and the way we live in it – Henry Ford, Thomas Edison, the Wright Brothers and Jack Kilby,” TI Chairman Tom Engibous said in a statement Tuesday. “If there was ever a seminal invention that transformed not only our industry but our world, it was Jack’s invention of the first integrated circuit.”

Kilby was born in 1923 in Great Bend. His father was the owner of a small electric company, and Kilby became interested in radio tubes while listening to big band radio in the 1940s. He earned degrees in electrical engineering from the universities of Illinois and Wisconsin, and began his career in 1947 with the Centralab Division of Globe Union Inc. in Milwaukee, developing ceramic-based, silk-screened circuits for electronic products.