Thomas Edison applied for his first patent in 1868 when he was only 21 years old. The first original idea of the famous inventor was for a device that recorded legislative votes. It was only the beginning of a career in which he would obtain 1,093 American patents, in addition to 500 to 600 applications which he had not completed or which had been rejected. But Edison’s greatest invention may have been to develop a new process for coming up with inventions.
“When Edison raised huge capital, built a laboratory in Menlo Park, NJ, and hired a team of dozens, each with distinct talents, he was the pioneer of what became the research and development process for modern business, “says Ernest Freeberg, historian at the University of Tennessee, Knoxville and author of The Age of Edison: Electric Light and the Invention of Modern America.
“He saw it as an invention factory, a factory that would produce surprising new products at a regular rate.”
In many cases, Edison’s genius took a new technology that someone else had launched and developed a superior way of doing the same. “An invention must not only work well enough, but it must be something the market wants and can afford to buy. Edison understood this as well as anyone in his time, ”said Freeberg.
Here are some of Edison’s most important inventions.
While Samuel Morse’s invention on the the telegraph in the 1830s and 1840s made it possible for the first time to communicate over long distances, the device had its drawbacks. An operator had to listen to incoming dots and dashes in Morse code, which slowed messages down to 25 to 40 words per minute. A British automatic ink code printing system on paper was only 120 words maximum.
Between 1870 and 1874, Edison developed a vastly superior system, in which a telegraph receiver used a metal stylus to mark chemically treated paper, which could then be passed through a typewriter-type device. It was able to record up to 1,000 words per minute, making it possible to send long messages quickly.
Carbon phone transmitter
It was Alexander Graham Bell who patented the phone in 1876. But Edison, with his talent for building on the innovations of others, found a way to improve the Bell transmitter, which was limited to the extent that the telephones could be separated by a weak electric current. Edison came up with the idea of using a battery to provide power over the telephone line and to control its strength by using carbon to vary the resistance. To do this, he designed a transmitter in which a small piece of smoke black (a black carbon made from soot) was placed behind the diaphragm. When someone spoke into the phone, the sound waves moved the diaphragm and the pressure on the lamp black changed. Edison later replaced the smoke black with charcoal pellets – a basic design that was used until the 1980s.
Contrary to popular belief, Edison did not really invent the incandescent bulb. But he invented and marketed a design that was the first to be durable enough to be practical for widespread use.
“Edison was one of half a dozen people who assembled the elements of a viable lighting system over those years, and as Edison was late for the race, he benefited from all of his predecessors and rivals” says Freeberg.
In the late 1870s, Edison designed a vacuum bulb, in which a metallic filament could be heated to create light. One night, after having absentmindedly absentmindedly between his fingers a piece of black smoke, the material he used in his telephone receiver, he had the idea to switch to a charred filament. After initially using charred cardboard, he started experimenting with other materials and eventually settled on bamboo, which had long fibers that made it more durable. Ultimately, the combination of bamboo filaments and an improved vacuum pump that removed air more efficiently allowed Edison to increase the life of the bulbs to approximately 1,200 hours.
While developing his telephone transmitter, Edison had the idea of creating a machine capable of recording and reading telephone messages. This notion led him to imagine being able to record not only voices, but music and other sounds, using sound to vibrate a diaphragm and push a stylus which made indentations on a cylinder covered with waxed paper which was turned by a crank.
At the end of 1877, he had a machinist built the device, using aluminum foil instead of wax, and Edison recorded the nursery rhyme “Mary Had a Little Lamb”. The following year, he obtained a patent for the design, which also included a lighter needle to find groves and transmit vibrations to a second diaphragm, which recreated the person’s voice.
Edison’s phonograph caused a sensation and helped strengthen his reputation as a great inventor. Eventually, he began to market and sell the machines and cylinder disks, resuming the use of wax. But by the early 1900s, the Victor Talking Machine Company phonographs that played records outstripped the popularity of Edison’s cylinder phonographs. Even though the cylinders produced better sound, early discs had a big advantage in that they could hold four minutes of music, compared to the two minutes that could fit on a cylinder.
Video camera and viewer
In the late 1880s, Edison oversaw the development by his laboratory of technology “that does for the eye what the phonograph does for the ear.” Most of the work on the Kinetograph, a former movie camera, and Kinetoscope, a viewer of single peephole, were in fact executed by Edison’s employee, William Kennedy-Laurie Dickson. The cinema became a big industry and the camera and the spectator of Edison were quickly replaced by innovations such as the Light Cinematograph, a combination camera, printer and projector which allowed the public to watch a film together. But Edison adapted and his company became a successful film studio at first, producing dozens of silent films between the 1890s and 1918, when production closed.
Alkaline storage battery
When the automobile was first developed in the late 1800s, electric vehicles were more popular than those equipped with gasoline internal combustion engines. But the first electric cars had a big drawback: the batteries they used were heavy and acid leak, which corroded the interior of cars.
Edison decided to take up the challenge of inventing a lighter, more reliable and more powerful battery. After conducting extensive research and the embarrassing flop of a first design, Edison developed a reliable alkaline battery, and in 1910 began production. His work, however, was soon overshadowed by Henry Ford’s development of the inexpensive Model T car that ran on an internal combustion engine. Nevertheless, Edison’s storage battery has been used in mines, trains and mining submarines and has become the most successful product in Edison’s last career.