Retrotechtacular: Manufacturing Philco Germanium Transistors

There was a time when all major corporations maintained film production departments to crank out public relations pieces, and the electronic industry was no exception. Indeed, in the sea-change years of the mid-20th century, corporate propaganda like this look at Philco transistor manufacturing was more important than ever, as companies tried to pivot from vacuum tubes to solid-state components, and needed to build the consumer electronics markets that would power the next few decades of rapid growth.

The film below was produced in 1957, just a decade since the invention of the transistor and only a few years since Philco invented the surface-barrier transistor, the technology behind the components. It shows them being made in their “completely air-conditioned, modern plant” in Pennsylvania. The semiconductor was germanium, of course — the narrator only refers to “silly-con” transistors once near the end of the film — but the SBT process, with opposing jets of indium sulfate electrolyte being used to both etch the germanium chip and form the collector and emitter of the transistor, is a fascinating process, and these transistors were quite the advance back in the day. It’s interesting, too, to watch the casual nature of the manufacturing process — no clean rooms, no hair nets, and only a lab coat and “vacuum welcome mats” to keep things reasonably clean.

As in most such corporate productions, superlatives abound, so be prepared for quite a bit of hyperbole on the part of the Mid-Atlantic-accented narrator. And we noticed a bit of a whoopsie near the end, when he proudly intoned that Philco transistors would be aboard the “first Earth satellite.” They were used in the radio of Explorer 1, but the Russians had other ideas about who was going to be first.

And speaking of propaganda, don’t forget that at around this time, vacuum tube companies were fighting for their lives too. That’s where something like this designer’s guide to the evils of transistors came from.

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The Simplest Microwave Receiver

We are used to microwave receivers requiring complex chipsets and exacting PCB layouts, but as [CHZ-soft] has shown, it does not always have to be that way. With nothing more complex than a germanium point-contact diode and an oscilloscope, you can quickly, easily, and cheaply resolve microwave signals, as we are shown with a 2.4GHz wireless mouse.

Of course, there’s nothing new here, what we’re being shown is the very simplest incarnation of a crystal set. It’s a wideband device, with only the length of the wires providing any sort of resonance, but surprisingly with the addition of a very selective cavity resonator it can be turned into a useful receiver. Perhaps the most interesting take-away is that the germanium point-contact diode — once a ubiquitous component — has almost entirely disappeared. In most applications it has been supplanted by the Schottky diode, but even those usually don’t quite possess the speed in the point contact’s home ground of radio detection. This is a shame, because there are still some bench-level projects for which they are rather useful.

So if you have a point contact diode and AM radio doesn’t attract, give it a go as a microwave detector. And if the point contact diode has attracted your interest then you may want to read our piece on Rufus Turner, who brought us its archetype, the 1N34A.

Via Hacker News.

Profiles In Science: Jack Kilby And The Integrated Circuit

Sixty years ago this month, an unassuming but gifted engineer sitting in a lonely lab at Texas Instruments penned a few lines in his notebook about his ideas for building complete circuits on a single slab of semiconductor. He had no way of knowing if his idea would even work; the idea that it would become one of the key technologies of the 20th century that would rapidly change everything about the world would have seemed like a fantasy to him.

We’ve covered the story of how the integrated circuit came to be, and the ensuing patent battle that would eventually award priority to someone else. But we’ve never taken a close look at the quiet man in the quiet lab who actually thought it up: Jack Kilby.

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Robert Hall And The Solid-State Laser

The debt we all owe must be paid someday, and for inventor Robert N. Hall, that debt came due in 2016 at the ripe age of 96. Robert Hall’s passing went all but unnoticed by everyone but his family and a few close colleagues at General Electric’s Schenectady, New York research lab, where Hall spent his remarkable career.

That someone who lives for 96% of a century would outlive most of the people he had ever known is not surprising, but what’s more surprising is that more notice of his life and legacy wasn’t taken. Without his efforts, so many of the tools of modern life that we take for granted would not have come to pass, or would have been delayed. His main contribution started with a simple but seemingly outrageous idea — making a solid-state laser. But he ended up making so many more contributions that it’s worth a look at what he accomplished over his long career.

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Clive Sinclair, The Other Author

A reasonable selection of the Hackaday readership will have had their first experiences of computing on an 8-bit machine in a black case, with the word “Sinclair” on it. Even if you haven’t work with one of these machines you probably know that the man behind them was the sometimes colourful inventor Clive (now Sir Clive) Sinclair.

The finest in 1950s graphic design, applied to electronics books.
The finest in 1950s graphic design, applied to electronics books.

He was the founder of an electronics company that promised big results from its relatively inexpensive electronic products. Radio receivers that could fit in a matchbox, transistorised component stereo systems, miniature televisions, and affordable calculators had all received the Sinclair treatment from the early-1960s onwards. But it was towards the end of the 1970s that one of his companies produced its first microcomputer.

At the end of the 1950s, when the teenage Sinclair was already a prolific producer of electronics and in the early stages of starting his own electronics business, he took the entirely understandable route for a cash-strapped engineer and entrepreneur and began writing for a living. He wrote for electronics and radio magazines, later becoming assistant editor of the trade magazine Instrument Practice, and wrote electronic project books for Bernard’s Radio Manuals, and Bernard Babani Publishing. It is this period of his career that has caught our eye today, not simply for the famous association of the Sinclair name, but for the fascinating window his work gives us into the state of electronics at the time.

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Adding Optics To A Consumer Thermal Camera

[David Prutchi] writes in to tell us about his recent experiments with building lenses for thermal imaging cameras, which to his knowledge is a first (at least as far as DIY hardware is concerned). With his custom designed and built optics, he’s demonstrated the ability to not only zoom in on distant targets, but get up close and personal with small objects. He’s working with the Seek RevealPro, but the concept should work on hardware from other manufacturers as well.

In his detailed whitepaper, [David] starts by describing the types of lenses that are appropriate for thermal imaging. Glass doesn’t transmit the wavelengths that thermal camera is looking for, so the lenses need to be made of either germanium or zinc selenide. These aren’t exactly the kind of thing you can pick up at the local camera shop, and even small lenses made of these materials can cost hundreds of dollars. He suggests keeping an eye out on eBay for surplus optics you could pull them out of to keep costs down.

Creating the macro adapter is easy enough, you simply put a convex lens in front of the thermal camera. But telephoto is a bit more involved, and the rest of the whitepaper details the math and construction techniques used to assemble it the optics. [David] gives a complete bill of materials and cost breakdown for his telephoto converter, but prepare for a bout of sticker shock: the total cost with all new hardware is nearly $500 USD. The majority of that is for the special lenses though, so if you can score some on the second-hand market it can drop the cost significantly.

We’ve seen an impressive array of thermal camera hacks and projects recently, no doubt due to the falling prices of consumer-level imaging hardware. Given their utility as a diagnostic tool, a thermal camera might be something worth adding to your bag of tricks.

Calculating Like It’s 1962

We sometimes forget that the things we think of as trivial today were yesterday’s feats of extreme engineering. Consider the humble pocket calculator, these days so cheap and easy to construct that they’re essentially disposable. But building a simple “four-banger” calculator in 1962 was anything but a simple task, and it’s worth looking at what one of the giants upon whose shoulders we stand today accomplished with practically nothing.

If there’s anything that [Cliff Stoll]’s enthusiasm can’t make interesting, we don’t know what it would be, and he certainly does the job with this teardown and analysis of a vintage electronic calculator. You’ll remember [Cliff] from his book The Cuckoo’s Egg, documenting his mid-80s computer sleuthing that exposed a gang of black-hat hackers working for the KGB. [Cliff] came upon a pair of Friden EC-132 electronic calculators, and with the help of [Bob Ragen], the engineer who designed them in 1962, got one working. With a rack of PC boards, cleverly hinged to save space and stuffed with germanium transistors, a CRT display, and an acoustic delay-line memory, the calculators look ridiculous by today’s standards. But when you take a moment to ponder just how much work went into such a thing, it really makes you wonder how the old timers ever brought a product to market.

As a side note, it’s great to see the [Cliff] is still so energetic after all these years. Watching him jump about with such excitement and passion really gets us charged up.

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