Sixty years ago this month, scientists at Bell Labs demonstrated the most important invention of the 20th century: the first real transistor.
It’s hard to say when the electronics age started, but William Sturgeon’s 1825 development of the electromagnet laid the seeds that led to Joseph Henry’s crude telegraph in 1830, which was the first electrical system used to communicate over long distances (a mile). Just 14 years later, Samuel Morse sent a message by telegraph over a 40-mile link he had strung between Washington DC and Baltimore.
Considering the primitive nature of telegraphy at the time, it’s astonishing just how quickly the demand grew. By 1851 Western Union was in business, and in the same decade Cyrus Field had connected the Old and New Worlds via a fragile cable that failed a mere three weeks after the first message was sent. But later attempts succeeded. Instantaneous transatlantic communication quickly lost its novelty.
Although Alexander Graham Bell’s 1875 invention of the telephone is universally lauded today, it was a less than practical device till Thomas Edison came up with the carbon microphone two years later. The speaker’s voice modulated a pack of carbon granules, changing the circuit’s resistance and thus sending a signal to the receiver.
A number of inventors soon came up with the idea of wireless transmission, codified by Guglielmo Marconi’s 1896 patent and subsequent demonstrations. Like the telephone and telegraph early radios used neither CPUs, transistors, nor vacuum tubes. Marconi, drawing on the work of others, particularly Nikola Tesla, used a high voltage and spark gap to induce electromagnetic waves into a coil and an antenna. The signals, impossibly noisy by today’s standards, radiated all over the spectrum . . . but they worked. In fact, Titanic’s famous SOS was broadcast using a 5 KW spark gap set manufactured by the Marconi Wireless Telegraph Company.
The circuits were electrical, not electronic.
Telephone signals, though, degraded quickly over distance while radio remained crude and of limited range. The world desperately needed devices that could control the flow of the newly discovered electron. About this time Ambrose Fleming realized that the strange flow of electricity in a vacuum Edison had stumbled on could rectify an alternating current, which has the happy benefit of detecting radio waves. He invented the first simple vacuum tube diode. But it didn’t find much commercial success due to high costs and the current needed by the filament.
