Before the invention of transistors, vacuum tubes made radio possible

Before transistors, which regulate the flow of electricity, vacuum tubes—glass tubes containing no gas that resemble light bulbs—served as the electronic switches in computers.

Watch a timeline of the history of electricity, from observations of static electricity in antiquity to the War of the Currents—a rivalry to establish the ideal system for electric grids.

Tesla's alternating current power's most of the world's electric grids

In 1879, Thomas Edison’s light bulb relied on direct current, but such currents can't efficiently transmit power over long distances. Nikola Tesla introduced alternating current, which feature far fewer energy loses. Despite Edison’s attempts to discredit AC, Tesla proved its efficiency by lighting the 1893 Chicago World’s Fair.

A collective effort from multiple scientists and inventors led to the light bulb

While Thomas Edison's thin carbon filament design made light bulbs commercially viable, prior contributions, such as Joseph Swan's development of the first successful incandescent filament electric lamp, made its eventual invention possible.

Named after Nikola Tesla, who pioneered alternating current power systems, the Tesla coil was the first device to wirelessly transmit electricity.

Transistors are the foundational components of integrated circuits and microchips and manage the processing of electronic signals by controlling the flow of electricity.

Thomas Edison publicly executed animals with AC to convince the public of its dangers

J.P. Morgan first backed Thomas Edison's direct current system, seeing electricity's potential to usurp John D. Rockefeller's kerosene empire. Despite the investments and smear campaign against alternating current, alternating current ultimately won public support after lighting the 1893 World's Fair, after which Morgan would fund Tesla's wireless transmission tower.

Cathode rays are beams of electrons that emit light when hitting a fluorescent screen

When these beams are emitted into an evacuated tube containing charged plates or a nearby magnet, deflections are observed due to the electron charge. In 1897, J.J. Thomson's calculations of this deflection led to his discovery of the subatomic particle.

Despite promoting alternative current, Nikola Tesla did not invent it

The technology was developed by Hippolyte Pixii in 1832, almost 25 years before Tesla was born. Other myths about Tesla include that he invented the transformer, radio, and the induction coil, which was invented by Nicholas Callan in 1836.

Transistors in traditional computers are physically limited to atomic scales

As computer parts shrink, transistors—tiny switches that control the path of electrical signals—become obsolete because electrons can quantum tunnel through switch barriers. This makes quantum computers, which take advantage of quantum effects, an enticing alternative.

The disputed inventor of the radio

Guglielmo Marconi was awarded the 1909 Nobel Prize in physics for inventing the wireless telegraph, which used radio waves to transmit Morse code. Nikola Tesla, however, was experimenting with radio waves in the 1890s, though much of his work was destroyed in a 1895 fire.

The history of many kitchen appliances involves unexpected discoveries and applications, including wartime radar turned hamster defroster and replacing an 'ice king' with heat-stealing boxes.

Cathode-ray tube televisions are examples of electron accelerators

CRT TVs work by converting electricity into heat, which causes electrons to be emitted from the rear of the device in three beams responsible for the colors red, green, and blue. Electromagnets direct electrons to phosphor molecules on the screen, which emit light and illuminate the pixels.

Guglielmo Marconi overshadowed Nikola Tesla through commercialization

Despite Tesla envisioning wireless power and communication earlier, Marconi developed practical implementations of wireless communication, including transmitting the first transatlantic radio signal. The technology, which facilitated telegraphy critical for warships and navies, earned Marconi the 1909 Nobel Prize in physics.

Electromagnetic induction creates electricity from a changing magnetic field

The phenomenon was discovered in 1831 by Michael Faraday when an electric current was induced in a wire wrapped around an iron ring after a second wrapped wire not connected to the first was connected or disconnected from a battery.

Tesla's first successful AC prototype used a metal shoe polish tin for a rotor

After leaving his position working with Thomas Edison, Tesla partnered with George Westinghouse to promote alternating current systems as a more viable, scalable solution to electricity transmission.

Thomas Edison created the first strand of electric Christmas lights in 1880

Edison strung electric bulbs outside his laboratory in 1880, and his business partner Edward H. Johnson first wrapped a tree in lights in 1882. It wasn’t until the lights were commercialized in 1917 that they became common in household Christmas decorations.

Why Edwin Armstrong developed FM radio

AM radio was popular but prone to interference and static, which could be frustrating for listeners. In 1933, Armstrong, a Columbia University professor, discovered that a clearer signal could be broadcast by revising how it was captured.

In 1898, Nikola Tesla wowed a crowd by controlling a boat with no visible connection

Some onlookers thought it was a trick, such a a monkey being inside the boat, rather than mind control or some other metaphysical phenomenon. In reality, Tesla was pioneering radio waves, proving wireless control was possible.

In 1880, Jacques and Pierre Curie discovered that electricity could be produced by striking certain materials—the piezoelectric effect—a phenomenon that is seen in barbecue lighters.

A dispute about the origin of twitching frog legs led to the invention of the first battery

Experiments by Luigi Galvani on exposed frog leg nerves showed activity when they were hung from iron railings and brass hooks, suggesting the existence of "animal electricity" that discharged when connected to metals. Alessandro Volta's voltaic pile, which stacked metals with an inorganic electrolyte, showed that electricity originates from chemical reactions.

Thomas Edison, eager to communicate with ghosts, tinkered with an apparatus called the 'spirit phone.'

Alternating current was used to commit the first execution by electric chair

Dubbed the "executioner's current," the device was designed in Thomas Edison's lab by Harold Brown—an opponent of George Westinghouse and Nikola Tesla. The effort aimed at discrediting AC technology and gain favor for Thomas Edison's direct current as part of "The Current War."

CES debuted in 1967 amid a wave of miniaturization in at-home electronics

The rapid development of integrated circuits—the basis of computing power—in the 1960s catalyzed an industrial shift toward miniature devices, including pocket transistor radios, smaller TVs, and more. This first consumer electronics trade show (with a slate of 117 exhibitors and 17,000 attendees) sought to make everyday electronics accessible and portable. See a timeline of early consumer tech with photos.

The electric microphone led to a country music boom

The electric microphone provided enhanced audio and greater portability, saving the fledgling record industry and making recording outside of New York and Camden, New Jersey, possible. This proved critical for capturing early country and rock ‘n’ roll.

Benjamin Franklin described a series of static electricity storage jars as 'batteries'

Discovered over 50 years before the first electrochemical cell was invented, Leyden jars stored electric charge between the metals inside and outside a liquid-filled container. Franklin was the first to use the term "battery" in an electrical sense, though his multiple-jar device—lacking chemical reactions—was actually a series of capacitors.

See a timeline of commercial radio history

Radio, as we know it, began in the 1910s. This FCC timeline traces the evolution of the medium over the century that followed, highlighting groundbreaking broadcasts, speeches, and technological breakthroughs.

If two strands of conducting materials are connected at two junctions, electricity can be generated if one junction is heated while the other is cooled—a phenomenon known as the Seebeck effect.

Nikola Tesla embraced showmanship when promoting ideas ahead of their time

He once electrified himself during a live demonstration to illustrate the safety and power of alternating current, and his presentations often featured arcing coils, glowing lights, and bold claims about a future of wireless power.

There is a limit to how small transistors can become because they rely on being able to allow or block the flow of electrons, but quantum effects allow electrons to leak through these barriers, generating heat, current loss, and potential data errors.

Before 1932, when particle accelerators were first used for nuclear research, scientists relied on naturally radioactive substances to advance their understanding of the atomic nucleus.

Nikola Tesla's biggest dream was a worldwide network of wireless power transmission

He built the Wardenclyffe lab and a massive prototype transmission tower to develop trans-Atlantic transmission, but it was never operational. The concept was based on incorrect assumptions about Earth's conductivity, but it inspired subsequent efforts for wireless systems.

Niagara Falls helped decide the battle between AC and DC power

In the 1890s, Niagara Falls became the proving ground for alternating current (AC) when Tesla and Westinghouse built the first large-scale AC hydroelectric plant—defeating Edison’s push for direct current (DC) in the US electrical system.

X-rays earned the very first Nobel Prize in physics for revealing hidden worlds

In 1895, Wilhelm Conrad Röntgen discovered X-rays, which could pass through solid objects and make unseen structures visible. Today’s X-ray tools continue to advance science and medicine, including capturing real-time images of proteins.

Before Silicon Valley, the American innovation hub was New Jersey

Today, Silicon Valley is known for its dominance in the tech world. But before it rose to prominence, New Jersey was the country's innovation hub. From Thomas Edison's light bulb to the transistor, New Jersey was considered the nation's leader in technology.

By igniting flammable gas in a tube filled with holes and playing music into it, the fire will take the shape of the sound waves, enabling the visualization of audio.

Explore a gallery of electric vehicles from before 1920

In 1884, Thomas Parker invented the first practical electric car in London. By the turn of the century, early EVs were seen on the streets of Washington, DC. Automaker promotional materials included photographs of cars on mountain roads and other terrains.

Microphone technology made crooning possible

Before the electric microphone, vocalists needed to project to have their voices captured. The new technology, however, made softer, more intimate singing possible, leading to a new style of singing that took off in the late 1920s, with "crooners" becoming some of the first American pop stars.

Thomas Edison inadvertently spurred the film industry's move to Hollywood

The inventor's patent on the motion picture camera included several stipulations that required independent movie studios to work with Edison's Motion Picture Patents Co., making the East Coast undesirable for aspiring filmmakers.

The first tattoo gun was based on an electric pen invented by Thomas Edison.

Nikola Tesla was born in modern-day Croatia and moved to the US in 1884

His interest in electricity came from his mother, who invented small household appliances during Tesla's upbringing. Upon arriving in America, he began working for and improving upon the electrical inventions made in Thomas Edison's lab.

Radio waves are used in broadcasting, weather radar, telecommunications, and GPS

Its ability to bend around obstacles and reflect off the ionosphere—an electrified layer of Earth's upper atmosphere—allows this type of light to travel long distances without damaging living things due to its low energy. MRI scanners, WiFi, and Bluetooth technologies are also applications of this form of light.

Fluorescent bulbs can be illuminated by overhead power lines without making contact

The electromagnetic fields produced by the alternating current in transmission lines can induce the motion of charges in nearby objects. This motion yields electric currents that can light up bulbs but are too small to harm humans.

Tesla's lack of business savvy and inability to commercialize led to his obscurity

For decades, despite pioneering technologies for large-scale electrical systems and telecommunications, Nikola Tesla had been forgotten to history. Rather than monetizing his work and becoming more well known, his inventor-first mentality saw him sell off lucrative patents to fund new experiments in the short term.

Contactless credit cards descend from a batteryless Cold War listening device

The same physics that let Soviet spies eavesdrop on the US ambassador in 1945 underlie contactless payment methods today. The device is a passive chip powered wirelessly by incoming radio waves.

Why were tanks invented?

Tanks first appeared in warfare in World War I. As old methods of conducting battles proved ineffective, the idea of an armored vehicle that could traverse almost any terrain and carry a cannon came to fruition. World War I provided the impetus and finances to develop the modern tank. Learn more in this short but detailed article.

Learn about the relationship between Thomas Edison and Henry Ford

Despite their 16-year age difference, legendary inventor Thomas Edison and Henry Ford developed a close relationship after meeting at a convention in New York. The two—alongside environmentalist John Burroughs and Harvey Firestone, the founder of Firestone Tire—were known as the "Four Vagabonds" and were famous for their long roadtrips, which were often highly publicized.

Transformers change the current and voltage across a set of wires by wrapping them around a magnetic core and using the magnetic field of one wire to induce a current in the other.

When a radio company was the biggest tech stock around

The Radio Corporation of America was the biggest stock during the 1920s. Originally called Marconi Wireless, the company transformed radio technology. The company pioneered broadcasting, created NBC, and became a tech giant. After remarkable growth and challenges, RCA was acquired by General Electric in 1986, marking the end of its 67-year independent existence.

See a timeline of Silicon Valley's greatest innovations

Silicon Valley is home to some of the biggest innovations of the last century. From radio communicators in the 1930s, to personal computers in the 1970s, the Valley has been the center of technological innovation for decades.