You could say that May 16 can be an electrifying day in history. Or at least a very energetic one. On this day in 1888, Nikola Tesla described what equipment would be needed to transmit alternating current over long distances. Remember, at this time, he was engaged in the “War of the Currents” with that douche, Edison, who was a backer of DC. The only problem with DC (the kind of energy you get out of batteries) is that you need retransmission stations every mile or so. With Tesla’s version, you can send that power a long way down the wires before it needs any bump up in energy.
Of course, it might help to understand in the first place what electric charge is. Here’s Nick Lucid from Science Asylum to explain:
But if you think that electric current flows through a wire like water flows through a pipe, you’re wrong, and there’s a really interesting and big difference between the one and the other, as well as between AC and DC current. DC, meaning “direct current,” only “flows” in one direction, from higher to lower energy states. This is why it drains your batteries, actually — all of the energy potential contained therein sails along its merry way, powers your device, and then dumps off in the lower energy part of the battery, where it isn’t inclined to move again.
A simplification, to be sure, but the point is that any direct current, by definition, loses energy as it moves. Although here’s the funny thing about it, which Nick explains in this next video: neither current moves through that wire like it would in a pipe.
Although the energy in direct current moves from point A to point B at the speed of light, the actual electrons wrapped up in the electromagnetic field do not, and their progress is actually rather slow. If you think about it for a minute, this makes sense. Since your battery is drained when all of the negatively charged electrons move down to their low energy state, if they all moved at the speed of light, your battery would drain in nanoseconds. Rather, it’s the field that moves, while the electrons take their own sweet time moving down the crowded center of the wire — although move they do. It just takes them a lot of time because they’re bouncing around chaotically.
As for alternating current, since its thing is to let the field oscillate back and forth from source to destination, it doesn’t lose energy, but it also keeps its electrons on edge, literally, and they tend to sneak down the inside edges of the wire. However, since they’re just as likely to be on any edge around those 360 degrees, they have an equally slow trip. Even more so, what’s really guiding them isn’t so much their own momentum forward as it is the combination of electricity and magnetism. In AC, it’s a dance between the electric field in the wire and the magnetic field outside of it, which is exactly why the current seems to wind up in a standing wave between points A and B without losing energy.
I think you’re ready for part three:
By the way, as mentioned in that last video, Ben Franklin blew it when he defined positive and negative, but science blew it in not changing the nomenclature, so that the particle that carries electrical charge, the electron, is “negative,” while we think of energy as flowing from the positive terminal of batteries.
It doesn’t. It flows backwards into the “positive” terminals, but that’s never going to get fixed, is it?
But all of that was a long-winded intro to what the Germans did on this same day three years later, in 1891. It was the International Electrotechnical Exhibition, and they proved Edison dead wrong about which form of energy transmission was more efficient and safer. Not only did they use magnetism to create and sustain the energy flow, they used Tesla’s idea of three-phase electric power, and if you’ve got outlets at home with those three prongs, frequently in an unintended smiley face arrangement, then you know all about it.
Obviously, the power of AC gave us nationwide electricity, but it also powered our earliest telegraph systems, in effect the great-grandparent of the internet. Later on, things sort of went hybrid, with the external power for landlines coming from AC power, but that getting stepped down and converted to operate the internal electronics via DC.
In fact, that’s the only reason that Edison’s version wound up sticking around: the rise of electronics, transistors, microchips, and so on. Powering cities and neighborhoods and so on requires the oomph of AC, but dealing with microcircuits requires the “directionality” of DC.
It does make sense though, if we go back to the water through a house analogy, wrong as it is. Computer logic runs on transistors, which are essentially one-way logic gates — input, input, compare, output. This is where computers and electricity really link up nicely. Computers work in binary: 1 or 0; on or off. So does electricity. 1 or 0; positive voltage, no voltage. Alternating current is just going to give you a fog of constant overlapping 1s and 0s. Direct current can be either, or. And that’s why computers manage to convert one to the other before the power gets to any of the logic circuits.
There’s one other really interesting power-related connection to today, and it’s this: on May 16, 1960, Theodore Maiman fired up the first optical LASER in Malibu, California, which he is credited with creating. Now… what does this have to do with everything before it? Well… everything.
LASER, which should only properly ever be spelled like that, is an acronym for the expression Light Amplification by Stimulated Emission of Radiation.
But that’s it. It was basically applying the fundamentals of electromagnetism (see above) to electrons and photons. The optical version of electrical amplification, really. But here’s the interesting thing about it. Once science got a handle on how LASERs worked, they realized that they could use to send the same information that they could via electricity.
So… all those telegraphs and telephone calls that used to get shot down copper wires over great distances in analog form? Yeah, well… here was a media that could do it through much cheaper things called fiber optics, transmit the same data much more quickly, and do it with little energy loss over the same distances.
And, ironically, it really involved the same dance of particles that Tesla realized in figuring out how AC worked way back in the day, nearly a century before that first LASER.
All of these innovations popped up on the same day, May 16, in 1888, 1891, and 1960. I think we’re a bit overdue for the next big breakthrough to happen on this day. See you in 2020?
What is your favorite science innovation involving energy? Tell us in the comments!