What was the most significant invention or idea that contributed in the creation of the modern computer?
Probably the most significant invention that led to the modern computer was its most basic component: the transistor. There are many types, but at their most basic leve, transistors are semiconductor devices that switch or amplify electric current. This is essentially what creates the 0 or 1 binary machine code that computers use. Previously, this role had been performed by vaccuum tubes which were inefficiently large and prone to error (even by invasion by physical insects, hence the term "bug.") Though several scientists contributed to the invention, the first true semiconductor transistor was developed by John Bardeen, William Shockley, and Walter Brattain of AT&T's Bell Labs in 1947. The trio received the Nobel Prize in Physics in 1956 for their work. Modern computers (indeed all electronic devices) owe their most fundamental functions to the transistor.