A new sort of active element was needed, something that produced less waste heat, used vastly fewer watts, and was reliable. Clearly, the advent of digital technology had pushed tubes to their very limits. Perhaps the crowning achievement of vacuum-tube technology was the ENIAC in 1946, which employed some 18,000. The invention of radar in World War II created heavier demands for active electronics. Increasing capability lead then, as it still does today, to ever-escalating cries for more features, speed, and functionality. Reputedly it cost $2,400 in 1940 (over $33k today). In the late 1960s, I had a military-surplus 1940-era RBC radio receiver that had 19 tubes. Radios originally sported just a few tubes but soon high-end units used dozens. It's rather ironic that this, the first active element, which predated the tube, was a semiconductor, but that nearly another half century was required to “discover” semiconductors. I can't find much about their origins, but it seems these crystals first appeared shortly before Fleming did his pioneering vacuum tube research. The very first active devices may have been cats whisker crystals, a bit of springy wire touching a raw hunk of galena that works as a primitive diode.

I think the difference between electrical and electronic circuits is that the latter uses “active” elements, components that rectify, switch, or amplify. By 1918, over a million a year were being made in the U.S., more than fifty times the pre-war numbers.Įlectronics is defined as “the science dealing with the development and application of devices and systems involving the flow of electrons in a vacuum, in gaseous media, and in semiconductors,” and the word came into being nearly at the same time the tube was created. During the four years of World War I, Western Electric alone produced a half million tubes for the U.S.

With the tube, engineers learned they could create radios of fantastic sensitivity, send voices over tens of thousands of miles of cable, and switch ones and zeroes in microseconds. Those are the basic operations of any bit of electronics. With this new control element, a circuit could amplify, oscillate, and switch. In the first decade of the new century, Lee de Forest inserted a grid in the tube between the anode and cathode. But it didn't find much commercial success due to high costs and the current needed by the filament. He invented the first simple vacuum tube diode. 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. The world desperately needed devices that could control the flow of the newly discovered electron. Telephone signals, though, degraded quickly over distance while radio remained crude and of limited range. The circuits were electrical, not electronic. In fact, Titanic's famous SOS was broadcast using a 5 KW spark gap set manufactured by the Marconi Wireless Telegraph Company. The signals, impossibly noisy by today's standards, radiated all over the spectrum.

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. Like the telephone and telegraph early radios used neither CPUs, transistors, nor vacuum tubes. A number of inventors soon came up with the idea of wireless transmission, codified by Guglielmo Marconi's 1896 patent and subsequent demonstrations.

Old transistor radio circuits