transistor One of the most important inventions in history, the transistor can be found in nearly every common electronic device manufactured today--radios, TV sets, cellular phones, computers, and so on. Originally created in the late 1940s by Bell Labs, the transistor was hailed as a smaller, less-expensive, and cooler-running replacement for the vacuum tubes then commonly used to amplify current in electronic devices. Today, millions of transistors are often packed into silicon chips to create the processors used in modern computers.