COMMUNICATIONS PIONEERS: Lee De Forest

None of it’s possible without an amplifier. If it weren’t for the amplifier, there would be no radio, no television, no satellites and no cell phones. All those technologies rely on radio waves that are too weak to be used without an amplifier. Signals that come from satellites are measured in tiny fractions of a watt. That’s the same measurement as light bulbs… and a 10 watt bulb is barely bright enough to read by. So how does this super-weak signal give you hundreds of channels? The answer is: it’s amplified.

Satellite signals are only amplified to a few hundredths of a watt, but the TV’s sound is amplified by hundreds of watts. It’s all done through the same principle and the person who invented the first commercially viable amplifiers was Lee De Forest.

Dr. De Forest was a first-class inventor with over 180 patents, but today he is most remembered for his invention of the Audion, which was the first tube amplifier. This would later be known as the vacuum tube, and the same principle would be incorporated as the transistor, the basis of all computer chips.

An amplifier does two things. First, it detects a signal coming through a wire. Second, it takes raw electrical power and modifies it so it carries the same signal but with much higher power. The resulting signal is strong enough to drive a speaker, display a video picture, or process a digital signal from a wireless device.

Dr. De Forest’s invention was the engine that drove technology for fifty years; from radio to computers, every device had a vacuum tube. Telephones didn’t need them because of huge trunk amplifiers built into the phone network. While tubes were unreliable, ran hot, and wasted energy, they were critical in our technological development until they were replaced in the 1960s by the transistor.

For the invention that made it possible to get picture and sound from millions of miles away, that made it possible to blast our tunes as loud as we want, we salute Dr. Lee De Forest.