One of the most important inventions of our times was announced in early July 1948 in a press release by Bell Laboratories in New Jersey — the transfer resistance device — far better known as the transistor. The small, simple, and tough transistor replaced fragile and heat-generating vacuum tubes, which had been the heart of electronics for decades. The discovery led to the development of the integrated circuit and the microprocessor that are the basis of modern electronics. Today, transistor technology makes possible the devices we take for granted in daily life — computers, cell phones, and video games, as well as satellites and medical equipment. Making semiconductors and other components for electronics is a $104 billion per year business employing 263,000 people in nearly 4,200 businesses. Profile America is in its 19th year as a public service of the U.S. Census Bureau.