History of the LED — the Movie 106
ptorrone writes "MAKE Magazine has a fantastic 'Connections'-style video called THE LED — The short documentary has the history of the LED to modern day applications. Starting with the work of Russian Oleg Vladimirovich Losev, which was largely ignored in the 1920s, to making your own 'Cat's Whisker' — a primitive LED made from a metal-semiconductor point-contact junction forming a Schottky barrier diode. The first practical visible-spectrum LED was developed in 1962 by Nick Holonyak Jr., while working at General Electric Company."
LED: The Movie (Score:5, Funny)
It was such an enlightening experience.
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'cats whisker' != a primitive led, it's a primitive diode, but it does not produce any light, visible or otherwise.
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it seems to in the video. although it's not the cat's-whisker detector itself that emits the light, it's the silicon carbide crystal that produces the illumination when the cat's whisker wire is touching certain places. the detector by itself without any crystal isn't a diode at all, and with other types of crystals is just a diode that doesn't produce any light.
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hm... mod me down please !
It seems that it is possible to get a point contact diode like this to emit light sporadically.
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Because a 'cats whisker' or detector diode never was intended to be a led, it is simply a side effect and only then with a specific kind of crystal and circuitry. It's intended use was to rectify currents, not to produce light.
To label it 'a primitive led' is a bit over the top, if it would have said 'which can be used to create a primitive kind of led' would have been a lot more accurate.
I've played countless hours with them as a kid when building crystal radio sets, never once seen one light up.
The wordin
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Very few electronic parts will fail to produce light, if biased properly.
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The LED Museum [att.net] seriously will enlighten you. What a classic.
The video was good, also.
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happy holidaes (Score:2)
SOLAR LEDs are the killer! (Score:2)
I've found the purely LED lighting to be reasonably priced, it's the SOLAR led fairy lights that are the killer.
I have a pretty darn large garden with many large trees, I'd love to have them all twinkling, but don't want power cables running all over the place. Solar fairy lights would be the answer if they weren't $70AUD or so for a couple of hundred globes.
Still, they are dropping, so, hopefully next year will be the year of a garden enveloped in light for no electrical cost.
Illuminating film (Score:3, Funny)
Re:Illuminating film (Score:5, Funny)
Re:Illuminating film (Score:5, Funny)
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Nonsense! Two atoms walk into a bar. The first says "I think I've lost an electron", and the second replies "Are you sure?", and the first one says "I'm positive"
The other took a closer look, but the wave function collapsed and the electron reappeared.
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Thanks! I'll be here all week. Tip your servers and avoid the crab louie like the plague!
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And if the disk crashed I'd be really screwed, all my backups are on it.
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Yeah, that's the word I was looking for! :(
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You mean a number equal to the number of bullets.
But that's not really true either -- the threat of violence can keep all 100 people in line. While it's true that working collectively they could overwhelm the man with the gun, anyone who tried -- particularly the first few -- have a good chance of getting shot. So unless there are several people willing to sacrifice themselves for the group, or are otherwise not deterred by the personal chance of being shot the threat of violence is sufficient, and the numb
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Wasn't this the basic dynamic of 9/11?
You can control a whole plane full of people with a few razor blades if everyone thinks that they are going to make it out alive either way. Everyone was familiar with the concept of the hijacking. The plane is brought somewhere, demands are made... hostages get released or rescued.
Nobody has any reason to risk their lives for the group, because, the general consensus is that this situation still can resolve itself without the hostages taking such risks.
Doesn't work so
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Even less if they're wearing kevlar...
Best not to overdrive them though (Score:4, Interesting)
Re:Best not to overdrive them though (Score:5, Funny)
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It took me a while before I figured out how to spot proper components that kept the magic smoke inside.
Yeah I tried resistors for that but they often became Smoke Emitting Resistors too.
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ok, since you guys are electronics geeks, can you answer this question for me--if an LED is just a silicon carbide/gallium arsenide/etc. crystal with two electrodes attached, then why does it matter which way the current is flowing? it seemed like in the YouTube video he just arbitrarily clipped an electrode onto one end of the SiC crystal, and then randomly touched the needle to the crystal in different places to create light.
in other words, what determines which end is the anode and which end is the catho
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Different points on the crystal have different electrical properties/conductivity.
The fact that it generates light when the probe touches a point does not necessarily mean that the crystal itself is a diode.
But certain points on the crystal may have diode-like properties.
http://en.wikipedia.org/wiki/Semiconductor#Explaining_semiconductor_energy_bands [wikipedia.org]
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If the diode is wired up in the forward mode, then the voltage potential helps close the gap, and current flows.
If the diode is wired up in the reverse mo
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well, when i was young, i put a red led into the 230V mains. the head part of the led went off like a bullet and stuck 1 cm deep into the wall.
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OTH seeing that you were using a breadboard maybe it took off under rocket power. Hmm that gets me thinking. 555s are pretty cheap you know.
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I got my first LEDs from Radio Shack. The packaging specified 1.5V forward voltage, so I figured an AAA cell would be fine. Not.
While Proust recalled his childhood through the taste of madeleines [wikipedia.org], a true geek gets zapped back by the smell of smoking epoxy.
Re:warning don't try at home! (Score:5, Interesting)
When I was a kid we would take a blue blade (old type of razor blade) and a piece of graphite from a lead pencil and by judiciously touching it just right would act as a diode and thus a receiver.
We made a one piece headset from a cardboard tack box and would wrap wire around a form with a small magnet glued inside on one side of the tackbox and the coil glued to the other side.
The first portable radio I ever saw other than the home made variety had small tubes in them and ran on batteries.
You must be old (Score:2)
My late grand father used to do that, too, when he was a kid. In fact I believe his own father had done that, too.
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Yeah, same here, except I would steal the small speaker from a public phone...ahh...the good old times in a communist country: no parts to buy, but plenty to steal from the common pot.
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Cool, Richard Dean Anderson is posting to slashdot!
Foxhole Radio (Score:2, Interesting)
http://bizarrelabs.com/foxhole.htm [bizarrelabs.com]
Baby Blues. (Score:4, Interesting)
Interesting. Thing I wonder is I remember when blue LEDS were difficult and expensive to produce. Now almost every piece of equipment I have has a blue LED on it.
Re:Baby Blues. (Score:4, Funny)
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Blue LEDs have the highest intensity.
Also, they look cool, and now they are affordable. I mean, you couldn't get them, now you can, therefore you do.
Re:Baby Blues. (Score:5, Informative)
Oh god please, don't say they look cool. If one more thing in my house has a blue LED I'm never going to be able to get a night's sleep ever again. The damn things are like portals into a strange neon blue hell.
Electrical tape works wonders, though.
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Electrical tape works wonders, though.
So does the 'off' switch...
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At least it doesn't blink, like the power led on Dells in standby mode. What were they thinking?
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At least it doesn't blink, like the power led on Dells in standby mode. What were they thinking?
Oh, that's easy: "How can we rip off Apple's 'heartbeat' sleeping light, but make it more annoying?"
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So does the 'off' switch...
Interesting difference between the US and UK: while I was puttering around Scotland, I noticed that all electronic equipment had a real off switch - not just a mamby pamby standby switch. I like the idea of being able to turn stuff off for real, not just into 'save 10%' standby mode.
The first instance I can remember of something not being 'off' when off was a TV back in the 70's (?) that was marketed as being 'instant on'. It must've kept all the filaments hot (or at least warm)
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I prefer the soldering iron approach. :)
30 seconds later no more lights.
Re:Baby Blues. (Score:5, Funny)
I might try this sometime. Should I apply the soldering iron to the LED or the product designer?
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If some gadget has a bright LED I replace it with one of those. No more glare for me!
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My new alarm clock uses them to illuminate the display and it's been keeping me from getting to sleep at night.
yeah, there's some research into this. Get a red clock. Apparently other colors screw with your melatonin levels because your evolutionary ancestors needed to be more weary of being eaten on nights with a full moon. It's been implicated in leukemia in children since melatonin also has an anti-cancer effect. How sound the theory is I don't know, but at least it helps me sleep better and putting
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Maybe the source of your grief is not so much the blue hue as the intensity of the glow - the halo would contribute to the eeriness. Ever tried to tame them with something translucid, like window film or magic marker? You could also change the series resistor, if available.
Then again, maybe I'm all wrong and there is something about blue light that stimulates us humans the wrong way.
(if you see the above in an AC post, that was me by mistake)
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Blue LED's do look cool. It's just that the collective mass of gadget designers have taken 'cool' and extrapolated it to mean 'must have fourteen per square inch of gadget'.
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The problem is that they all seem to feel like they need to put the flashlight-bright blue LEDs in everything. I've seen red LEDs that are just as bright, but I generally don't see them used as status indicators, so why are blue LEDs different?
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Because blue is a different wavelength of light, which appears a lot more intense to our eyes.
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Amen. I sit in front of large RAIDs from time to time and these days the drives all have blue activity lights. It drives me crazy and irritates my eyes after a while. Far worse than the good old green and red LEDs.
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Re:Baby Blues. (Score:4, Informative)
Yep. A Japanese researcher, Nakamura, finally figured out how to do it and the company he worked for made a fortune overnight. He finally had to sue them for royalties, since the company was making bank and gave him a measly $200 to show their appreciation).
He finally got a $190 million dollar settlement. The company actually made six times that in royalties, and the judge said that he was actually entitled to half, but Nakamura only asked for $190 million, so that's what he got.
http://search.japantimes.co.jp/cgi-bin/nn20040131a1.html [japantimes.co.jp]
And yet... (Score:2)
Good video, small flaw. (Score:4, Informative)
Overall a very good video, but there is a small flaw. The video incorrectly notes that Oleg Vladimirovich Losev was a scientist in Imperial Russia... While Oleg Vladimirovich Losev was born in Imperial Russia, by the time he was working on diodes, it was the Soviet Union.
Other than that, an excellent video that only left we with the question, where do you get chunks of carborundum?
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Silicon, not Silicone (Score:3, Informative)
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silicone is not a single compound, there are many different silicones which are polymers containing silicon.
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Guess which one geeks are more likely to get their hands on?
BTW, silicone is used as a sealant and makes a good lubricant, too. You know, for hinges and stuff. Yeah... hinges.
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I really hate this Nerd Chic thing. One look at the people doing it tells you they are not really nerds, more like art school hipsters. Hell the whole point of Nerds is that they don't like being in the spotlight and have a crap sense of aesthetics. Some douchebag self promotionist with a Mac and a CSS rich 'collaborative blogging' website is not a nerd.
Nice to be reminded! (Score:2)
What am I saying? Production values on this are just bad enough, it remin
Risky Business (Score:2, Insightful)
It's too bad the narrator tried to demonstrate his circuit-design skills. Near the end of the video he powers an LED by connecting it directly across a disc battery. The only reason he didn't burn up his LED is because the voltages and temperatures were just right, but even that lucky break might have evaporated over a matter of minutes as the LED warmed up. When operating LEDs, you always want to have a current-limiting resistor or circuit in place -- always. The reason is that an LED's voltage/current/tem
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I read that you should consider the internal resistance of the battery, which as I recall, was rather high in those coin-size batteries.
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If you finish watching the movie, he actually goes on to say exactly that, and shows how to properly wire it with a resistor.
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The reason is that an LED's voltage/current/temperature relationship contradicts naive assumptions about electrical conductors.
To be specific, its that while a resistor will have a potential difference (voltage) proportional to the supply voltage, an LED's potential will never exceed a fixed voltage (IIRC its 1.5 V). Once the voltage exceeds this, you basically have a short circuit.
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The battery *is* the current limiting resistor. Those little coin batteries have high internal resistances, and are often used to power LEDs without resistors because of this.
Even then, limiting current needn't be done with a resistor, in fact, the last thing you want for high power LEDs is a resistor because the resistor will waste tremendous amounts of energy. Instead, for power illuminators you want a current source (as opposed to a voltage source). There are ICs available to do this, you set the current
He's no James Burke (Score:3, Insightful)
Philips Lighting and LED's (Score:2)
However, some of my friends working at the Lighting Division changed that to "LED's make things better"
Connections-like? How? (Score:3, Informative)
Neat video. But each Connections episode starts with some piece of technology, and traces it back to its almost surprising and seemingly unrelated origins. This starts with the LED... and traces back to the origins of the LED. No fantastic and surprising connections there. About the only true similarities I see is that The LED narrator and James Burke apparently share the same hairstylist and optomitrist.
Go back to the real beginning, please. (Score:1)