History of the Television
Televisions can be found in billions of homes around the world. But 100 years ago, nobody even knew what a television was. In fact, as late as 1947, only a few thousand Americans owned televisions. How did such a groundbreaking technology turn from a niche invention to a living room mainstay?
Today, we’re explaining the complete history of the television – including where it could be going in the future.
How Did Early Televisions Work?
The two types of televisions listed above, mechanical and electronic, worked in vastly different ways. We’ve hinted at how these TVs worked above, but we’ll go into a more detailed description in this section.
Mechanical televisions relied on rotating disks to transmit images from a transmitter to the receiver. Both the transmitter and receiver had rotating disks. The disks had holes in them spaced around the disk, with each hole being slightly lower than the other.
To transmit images, you had to place a camera in a totally dark room, then place a very bright light behind the disk. That disk would be turned by a motor in order to make one revolution for every frame of the TV picture.
Baird’s early mechanical television had 30 holes and rotated 12.5 times per second. There was a lens in front of the disk to focus light onto the subject.
When light hit the subject, that light would be reflected into a photoelectric cell, which then converted this light energy to electrical impulses. The electrical impulses are transmitted over the air to a receiver. The disk on that receiver would spin at the exact same speed as the disk on the transmitter’s camera (the motors would be synchronized to ensure precise transmissions).
The receiving end featured a radio receiver, which received the transmissions and connected them to a neon lamp placed behind the disk. The disk would rotate while the lamp would put out light in proportion to the electrical signal it was getting from the receiver.
Ultimately, this system would allow you to view the image on the other side of the disk – although you’d need a magnifying glass.
There’s a reason we stopped using mechanical televisions: electronic televisions were vastly superior.
Electronic televisions rely on a technology called a Cathode Ray Tube (CRT) as well as two or more anodes. The anodes were the positive terminals and the cathode was the negative terminal.
The “Cathode” part of the Cathode Ray Tube was a heated filament enclosed in a glass Tube (the “T” of CRT). The Cathode would release a beam of electronics into the empty space of the tube (which was actually a vacuum).
All of these released electrons had a negative charge and would thus be attracted to positively charged anodes. These anodes were found at the end of the CRT, which was the television screen. As the electrons were released at one end, they were displayed on the television screen at the other end.
Of course, firing electrons against a glass screen doesn’t make images. To make images, the inside of the television screen would be coated with phosphor. The electrons would paint an image on the screen one line at a time.
To control the firing of electrons, CRTs use two “steering coils”. Both steering coils use the power of magnets to push the electron beam to the desired location on the screen. One steering coil pushes the electrons up or down, while the other pushes them left or right.
The First Television Stations in America
The world’s first television stations first started appearing in America in the late 1920s and early 1930s.
The first mechanical TV station was called W3XK and was created by Charles Francis Jenkins (one of the inventors of the mechanical television). That TV station aired its first broadcast on July 2, 1928.
One of the world’s first television stations, WRGB, has the honor of being the world’s only continuously operating station since 1926 to the modern day.