We take electronics for granted today. But in its early days, it was a capricious and uncertain beast. My own grandfather was getting involved in that world just as all its new sophistication was making its way into our homes.
My grandfather, Jack, was one of the first television engineers. Back in his day, electronics could be loud and hot and were certainly capable of generating quite a pong—as my grandmother readily recalls. Her description of the sort of problem that he used to have to fix reminded me of that physicality about early electronics that’s easy to forget in these days of smartphones and Wi-Fi on tap – and also surprised me with her familiarity with all the components and processes. I’d never really heard her talk about anything technical in my life, and yet when it came to these old TVs, she was comfortable with specialized electrical terms I’d never come across. “Well,” she told me one day, “one important component was a line-output transformer, and when that went on the TV, it sometimes went with a bit of a bang but it also produced a burning sensation and a smell.” Her northern accent reminds me that this is almost certainly flat-capped understatement. Electrons have always been invisible, but from the 1940s to the 1970s you could definitely tell they were up to something. There was always the risk of a bang or a pop or a hiss, the sudden appearance of a sooty burnt patch or a flash of light that told you lots of energy had just been shunted somewhere it shouldn’t have gone. Jack found himself in at the beginning of the new world of television, part of the only generation that had a real feel for the electrical world. By the end of his career, transistors and computer chips had hidden it all away. The tiny exterior of these components conceals a vast and sophisticated interior, incomprehensible from the outside. But before they came along, there were a few decades when you could almost see the magic at work.
In 1935, at the age of sixteen, Jack had started a trade apprenticeship with Metropolitan Vickers, locally known as MetroVick. This giant of the heavy electronics engineering world was based in Trafford Park near Manchester, turning out world-class generators, steam turbines, and other large-scale electronics. When he finished his apprenticeship in electrical engineering at the age of twenty-one, he was classed as having a reserved occupation, deemed too useful to go to war, so he spent five years testing airplane gun electronics at MetroVick. The first test of these systems was called “flashing.” You put 2,000 volts across it and if it didn’t go bang, it passed. This was the raw end of the taming of the electron, the early stages of wrangling it into submission.
After the war, EMI was looking for people with electronics experience, because early televisions were skittish, complex beasts, needing an expert to set them up and frequent adjustment throughout their lifetimes. So EMI sent Jack to London to train as a television engineer. The tools of this trade were valves and resistors and wires and magnets, the components that could coax electrons to do your bidding. This visually beautiful potpourri of glass and ceramic and metal could be made to do something that sounds very simple, something that was at the heart of every television set until the 1990s. It could make a beam of electrons and then bend it; and if you do that right, you can make moving pictures.
Jack learned about “CRT” televisions, and I love that name because it connects us to the world that existed before electrons had even been discovered. CRT stands for cathode ray tube, and cathode rays were distinctly odd when they were first discovered. Imagine the early German physicist Johan Hittorf, in 1867, looking at his latest creation. In the gloomy lab, there’s a glass tube with two bits of metal sticking into the space inside at either end, and all the air inside the tube has been removed. This sounds fairly mundane. But imagine how odd it must have been to discover that if you connect a large battery to the two bits of metal, mysterious invisible stuff flowed from one end of the tube to the other. He could tell it was there, because it made the far end of the tube glow, and he could make shadows by putting things in the way. Even though no one knew what was flowing, it needed a name, so it became known as cathode rays. The cathode is the terminal attached to the negative end of a battery, and that’s where the strange stuff was coming from.
It was another thirty years before J. J. Thomson discovered that what was flowing wasn’t really rays at all, but a stream of individual negatively charged particles—the particles we now call electrons. By then it was too late to change the name of the apparatus, though, and it was still always called a cathode ray tube. We know today that applying a voltage across it generates an electric field stretching from one end to the other, and so electrons will hop off the negative end and rush toward the positive end. Any particle with an electric charge will be accelerated by the electric field, which means it will be constantly pushed along. So the electrons don’t just move toward the positive end because they’re attracted by it, they’re speeding up as they go. The higher the voltage difference between the two ends, the faster they’re going when they get to the other side. In a CRT TV, they can be going at more than a mile per second by the time they hit the screen. That’s a significant fraction of the speed of light, the fastest that anything in the universe can travel.
So the same basic process that led to the discovery of the electron in the first place was in use inside every TV in the world until a couple of decades ago. Each CRT TV has a device at the back that produces electrons. The middle of the TV is a completely empty chamber—a vacuum with no air in it—so there are no obstacles at all, and so the electrons “fired” from the “electron gun” stream across that empty space until they hit the screen. It’s the purest form of electrical current—charged particles moving in a straight line.
MY AUNT OPENS a box full of bits and pieces she saved from Jack’s workshop when he died. There are glass tubes that look like cylindrical lightbulbs, with a weird metallic insect-like structure inside each one. These are valves, used to control the flow of electrons in circuits. Early on, most of Jack’s job seemed to involve working out which one of these had malfunctioned, and replacing it. My mother, my aunt, and my grandmother clearly have a lot of affection for these, because there were so many of them around back then, and so many different types. And then in the corner of the box there’s a large circular magnet, now broken in half.