Philo T. Farnsworth

Television owes a lot to an unassuming young man working out of a small lab in San Francisco. His name was Philo T. Farnsworth and he invented a lot of what makes TV work today.

While formally educated, Mr. Farnsworth didn’t hold advanced degrees. He made electricity, and the idea of television, his passion and his own research far outpaced what was being done in universities at the time.

It’s the electrons, stupid

Unlike other pioneers at the beginning of the 20th century. Mr. Farnsworth believed that television should be all electronic. Early prototype TV systems from other inventors used physical masks and spinning wheels to cut up an image into small bits that could be transmitted electronically. It took the brilliance of Philo Farnsworth to realize that all the work could be done electronically.

The first viable video camera

When working on his family farm at the age of 15, Philo had an idea that would dominate broadcasting for nearly the next century. As he plowed his fields row by row, he realized that he could do the same with images. He could cut them apart row by row and then send each row one after the other. This solved the problem of how to send an entire video image at once. All he had to do was find a way to scan that image electronically.

(By the way, the half-frames produced by a traditional video camera are still called “fields.”)

By the age of 21, in 1927, Philo Farnsworth demonstrated the first prototype of what he called an “Image Dissector.” It was a special form of vacuum tube with a light sensitive surface. Light would be focused on the surface and then an electronic beam inside the tube would slice it up line by line. This created the first electronic television signal.

Farnsworth also invented what he called the “Image Oscillite” which was another form of tube that reassembled and displayed the images from the image dissector.

Put aside the problems of radio transmission, and that’s basically all television was for the next 75 years or so. Other inventors improved on the technology until it was perfected, but it all started with Farnsworth’s lab in San Francisco.

Mr. Farnsworth’s initial research is no longer used as all capture and display technology today is digital, but his contributions are still important.

Why vacuum tubes?

A lot of Farnsworth’s early work involved vacuum tubes. A vacuum tube is a glass tube where electronic components exist. All the air is pumped out, so that the heat from the components does less damage to them.

The vacuum tube was the miracle invention of the early 20th century. It could be used to control the flow of current, to amplify or modify it, or in the case of extremely complex tubes, to perform repetitive tasks electronically.

All electronics centered around vacuum tube technology until the mid-20th century, when the transistor was invented by scientists at AT&T’s facilities. The transistor is capable of doing nearly everything a vacuum tube can, but in a much smaller package, faster, and with less heat. This makes for more reliability. A transistor today is so small that a billion of them can fit in a 2″ x 2″ space, while a vacuum tube was typically about the size of a pill bottle or larger.

Vacuum tube technology basically went away after the invention of the transistor, with the exception of some amplifiers which are used in musical instruments and home audio because the sound produced by a tube amplifier is smoother than that produced by a digital amplifier.

In later life

Philo Farnsworth’s big contributions to society came early in his life and most of his days after that were spent working in labs trying to perfect his own inventions as well as that of others. He held over 300 patents including one for a small nuclear fusion device. Even though that device wasn’t a useful power plant, it still advanced the understanding of energy.

Mr. Farnsworth’s name isn’t really well known because he was one of many people who made television possible. The development of television would not have been possible without the prior development of radio, telephones, and electricity. In the years before radio and telegrams, inventors couldn’t work together. By the early 20th century, something as complex as television could be worked on by scientists all over the world, with each having access to each other’s work. Communication wasn’t as instant as it is today, but it was much faster than it had been.

Where you can say that one person invented the steam engine or the telegraph, there were dozens who perfected television. Philo T. Farnsworth deserves to be thought of as perhaps the dominant force, but let’s not forget all the others who contributed.

About the Author

Stuart Sweet
Stuart Sweet is the editor-in-chief of The Solid Signal Blog and a "master plumber" at Signal Group, LLC. He is the author of over 8,000 articles and longform tutorials including many posted here. Reach him by clicking on "Contact the Editor" at the bottom of this page.