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History of the LED — the Movie

timothy posted more than 5 years ago | from the some-dude's-bright-idea dept.

Hardware Hacking 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."

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LED: The Movie (5, Funny)

illumastorm (172101) | more than 5 years ago | (#25867419)

It was such an enlightening experience.

YouTube Illumination (2, Informative)

ibane (1294214) | more than 5 years ago | (#25867567)

here [youtube.com] .

Re:YouTube Illumination (1)

jacquesm (154384) | more than 5 years ago | (#25868103)

'cats whisker' != a primitive led, it's a primitive diode, but it does not produce any light, visible or otherwise.

Re:YouTube Illumination (1)

lysergic.acid (845423) | more than 5 years ago | (#25868375)

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.

Re:YouTube Illumination (-1)

jacquesm (154384) | more than 5 years ago | (#25868421)

an led produces light continuosly, a crystal detector (the proper name for this device) produces tiny sparks when you make the contact but that doesn't mean it's an led any more than your cars' sparkplug is.

Re:YouTube Illumination (0)

jacquesm (154384) | more than 5 years ago | (#25868463)

hm... mod me down please !

It seems that it is possible to get a point contact diode like this to emit light sporadically.

Re:YouTube Illumination (0)

Anonymous Coward | more than 5 years ago | (#25869439)

Why didn't you check BEFORE making such pretentious, professorial-sounding declarations of absolute truth?

Re:YouTube Illumination (1)

jacquesm (154384) | more than 5 years ago | (#25871363)

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 wording of the summary suggests with 'primitive kind of led' that that was its intended function, it was not. It was a 'primitive kind of diode', and with the right combination of crystal and current you can apparently make one light up.

Re:YouTube Illumination (1)

kandela (835710) | more than 5 years ago | (#25869017)

Well the ones on my cat never do! He seems to be powered (the engine is purring) but no light? What do I do?

Re:YouTube Illumination (1)

John Miles (108215) | more than 5 years ago | (#25870979)

Very few electronic parts will fail to produce light, if biased properly.

Sockpuppet Illumination (0)

Anonymous Coward | more than 5 years ago | (#25868603)

here [slashdot.org]

Re:LED: The Movie (2)

inKubus (199753) | more than 5 years ago | (#25869601)

The LED Museum [att.net] seriously will enlighten you. What a classic.

The video was good, also.

Re:LED: The Movie (1)

berend botje (1401731) | more than 5 years ago | (#25870727)

The LED museum was great when the guy running it kept to the history and technology of LEDs. The last few years he "reviews" flashlights and assorted crap. His prose, coupled with the byzantine webdesign, is hardly worth the very few bits of knowledge contained in the site. He had a good thing going, but he blew it.

happy holidaes (1)

negRo_slim (636783) | more than 5 years ago | (#25867431)

glad to see more selection in LED holiday lighting this year, the price premium is a bitch tho... but provides such a superior shine. anyways... where am i?

LIPSTICK (0)

Anonymous Coward | more than 5 years ago | (#25867627)

But can I get an LED to match the shade of lipstick this dude(?) is wearing????

SOLAR LEDs are the killer! (1)

spoco2 (322835) | more than 5 years ago | (#25868179)

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 (3, Funny)

lessthanpi (1333061) | more than 5 years ago | (#25867449)

This movie is to diode for

Re:Illuminating film (4, Funny)

MarkRose (820682) | more than 5 years ago | (#25867671)

Like, you can only resist the current of electronics jokes until the intensity of desire becomes too much and you breakdown, right?

Re:Illuminating film (5, Funny)

TheRealMindChild (743925) | more than 5 years ago | (#25867865)

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"

Re:Illuminating film (2, Funny)

syousef (465911) | more than 5 years ago | (#25869969)

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.

Re:Illuminating film (0)

Anonymous Coward | more than 5 years ago | (#25870211)

that groaning noise
it means people are in pain

Re:Illuminating film (2, Funny)

mudshark (19714) | more than 5 years ago | (#25870517)

You call that funny? It's just ionic.

Thanks! I'll be here all week. Tip your servers and avoid the crab louie like the plague!

Re:Illuminating film (1)

lostguru (987112) | more than 5 years ago | (#25870671)

I'm not gonna tip my server, I'm afraid the power cable might come loose and I'd lose my really high uptime.

And if the disk crashed I'd be really screwed, all my backups are on it.

Re:Illuminating film (0)

Anonymous Coward | more than 5 years ago | (#25868093)

replace intensity of desire with potential :P

Re:Illuminating film (1)

MarkRose (820682) | more than 5 years ago | (#25869331)

Yeah, that's the word I was looking for! :(

Re:Illuminating film (0)

Anonymous Coward | more than 5 years ago | (#25867795)

No, one man with a gun can control 100 men minus the number of bullets in the gun. After that, it's game over.

Re:Illuminating film (1)

profplump (309017) | more than 5 years ago | (#25868845)

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 number of bullets (or even their existence at all) is immaterial.

Re:Illuminating film (1)

TheCarp (96830) | more than 5 years ago | (#25873475)

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 well when you remove the possibility of peaceful outcomes.

Humans aren't so different from other animals. Take a cat... cats want no fight with a person. They know they can't win. They will run and hide and take any out from a fight.... but back them into a corner, and you will find far less hesitation in their fight.

As the Mahareeshi Hashish Yogi said "Many heros were cowards who ran the wrong way".

-Steve

Re:Illuminating film (1)

Miseph (979059) | more than 5 years ago | (#25869187)

Even less if they're wearing kevlar...

Best not to overdrive them though (3, Interesting)

MichaelSmith (789609) | more than 5 years ago | (#25867455)

Once when I was a very young geek I had an array of LEDs set up for some purpose. I accidently added 10V to the power supply due to a lack of attention and bad UI design. Every single LED burst. It smelt horrible and I got out of there fast. Switched off the power supply first though.

Re:Best not to overdrive them though (5, Funny)

MarkRose (820682) | more than 5 years ago | (#25867599)

I think someone swindled you. They obviously sold you SEDs: Smoke Emitting Diodes. I got taken several times myself as a kid. It took me a while before I figured out how to spot proper components that kept the magic smoke inside.

Re:Best not to overdrive them though (2, Funny)

MichaelSmith (789609) | more than 5 years ago | (#25867771)

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.

Re:Best not to overdrive them though (1)

MarkRose (820682) | more than 5 years ago | (#25867841)

One of my favourite tricks was making transistors sublimate. I was proficient lol

Re:Best not to overdrive them though (1)

renderitchaos (786314) | more than 5 years ago | (#25868931)

I learned two things in 4 years of Engineering: 1. You can't push on a rope. 2. Electronics run on smoke. If the smoke escapes, it won't work. Someone subsequently pointed out that Rule #1 needed modification: 1. You can't push on a rope - unless it's frozen.

Re:Best not to overdrive them though (0)

Anonymous Coward | more than 5 years ago | (#25868299)

Thank you. I was just about to do that, but now I won't.

Re:Best not to overdrive them though (1)

lysergic.acid (845423) | more than 5 years ago | (#25868517)

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 cathode in a commercial LED, and why does it matter?

Re:Best not to overdrive them though (2, Informative)

mysidia (191772) | more than 5 years ago | (#25868825)

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]

Re:Best not to overdrive them though (2)

HopeOS (74340) | more than 5 years ago | (#25869809)

Actually, diodes are typically made from two separate pieces of material that are joined. One side has a slight negative charge, the other positive. At the junction where they meet, the electrons rearrange across the boundary to balance out. This new arrangement leaves a "gap" where there are fewer electrons than are needed for current to freely cross.

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 mode, then the voltage potential increases the gap, and current is blocked.

In the case of light emitting diodes, as electrons cross the gap, some of them trigger photons. This happens in a deterministic manner, so the color is normally the same for each one.

-Hope

Re:Best not to overdrive them though (1)

dunkelfalke (91624) | more than 5 years ago | (#25868837)

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.

Re:Best not to overdrive them though (2)

HopeOS (74340) | more than 5 years ago | (#25869615)

When I was younger, I used the Radio Shack TI99-4/A power supplies to drive breadboard projects since they were readily available. One evening when I turned on the supply, the 555 on the breadboard exploded raining parts all over the dining room. My dad looked in, suggested I check my wiring. All the wires came up, and I rewired it meticulously. When I applied the power the second time, same result. A quick sanity check revealed that the power supply was outputting 25V on the 5V line. Made me wonder what kind of glorious failure modes the TI99 computers experienced.

-Hope

Re:Best not to overdrive them though (1)

MichaelSmith (789609) | more than 5 years ago | (#25870661)

I think I convinced a 14 pin TTL package to explode once but it blew out through the belly and just made a scorch mark on the PCB.

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.

Re:Best not to overdrive them though (1)

Anynomous Coward (841063) | more than 5 years ago | (#25871701)

Ah, you've been there too.

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.

warning don't try at home! (0)

Anonymous Coward | more than 5 years ago | (#25867459)

"making your own 'Cat's Whisker' â" a primitive LED made from a metal-semiconductor point-contact junction forming a Schottky barrier diode"

Man is my cat pissed at me.

Re:warning don't try at home! (5, Interesting)

Sanat (702) | more than 5 years ago | (#25867537)

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 (1)

Nicolas MONNET (4727) | more than 5 years ago | (#25868257)

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.

Re:warning don't try at home! (1)

vvaduva (859950) | more than 5 years ago | (#25868713)

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.

Re:warning don't try at home! (1)

elgatozorbas (783538) | more than 5 years ago | (#25868905)

Your name isn't Hertz by any chance?

Re:warning don't try at home! (1, Funny)

Anonymous Coward | more than 5 years ago | (#25869061)

Cool, Richard Dean Anderson is posting to slashdot!

Foxhole Radio (2, Interesting)

EkriirkE (1075937) | more than 5 years ago | (#25869613)

Soldiers in the (first) 2 World Wars used to make radios out of rusted razors, a safety pin (a cat's whisker diode) and a coil of wire (to tune)

http://bizarrelabs.com/foxhole.htm [bizarrelabs.com]

Baby Blues. (3, Interesting)

Ostracus (1354233) | more than 5 years ago | (#25867499)

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. (3, Funny)

MarkRose (820682) | more than 5 years ago | (#25867707)

So in other words, you're saying... they came out of the blue?

Re:Baby Blues. (2, Insightful)

fxkr (1343139) | more than 5 years ago | (#25867753)

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. (5, Informative)

Anpheus (908711) | more than 5 years ago | (#25867825)

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.

Re:Baby Blues. (1)

fxkr (1343139) | more than 5 years ago | (#25867917)

Electrical tape works wonders, though.

So does the 'off' switch...

Re:Baby Blues. (2, Interesting)

MarkRose (820682) | more than 5 years ago | (#25868019)

Except when some marketing genius decided to make the standby light a blue one...

Re:Baby Blues. (1)

Hal_Porter (817932) | more than 5 years ago | (#25870153)

At least it doesn't blink, like the power led on Dells in standby mode. What were they thinking?

Re:Baby Blues. (1)

glindsey (73730) | more than 5 years ago | (#25872333)

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?"

Re:Baby Blues. (1)

Fumus (1258966) | more than 5 years ago | (#25873027)

My Samsung SyncMaster 226BW has a blinking blue light when on standby...

Re:Baby Blues. (1)

Muad'Dave (255648) | more than 5 years ago | (#25872255)

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) all the time. Ouch!

Re:Baby Blues. (1)

cheater512 (783349) | more than 5 years ago | (#25868053)

I prefer the soldering iron approach. :)
30 seconds later no more lights.

Re:Baby Blues. (5, Funny)

Anonymous Coward | more than 5 years ago | (#25868761)

I might try this sometime. Should I apply the soldering iron to the LED or the product designer?

Re:Baby Blues. (1)

DNS-and-BIND (461968) | more than 5 years ago | (#25870649)

That would tend to void your warranty. Best to design the product without the bright LEDs. However, blinky lights are one of the things that customers like when they buy a product at the store, so it looks like the problem is here to stay. If you've got a choice between the ZhangTai DVD player with colored lights, and the RonsonCo DVD player that is a slim gray box that sits unobtrusively out of the way, you're going to pick the blinky one every time, especially if it's $0.99 cheaper than anything else on the shelf.

Re:Baby Blues. (1)

berend botje (1401731) | more than 5 years ago | (#25870751)

I have several hundred of those old pale yellowy/green LEDs that you really have to look at to see if it's on.

If some gadget has a bright LED I replace it with one of those. No more glare for me!

Re:Baby Blues. (1)

nategoose (1004564) | more than 5 years ago | (#25868227)

My new alarm clock uses them to illuminate the display and it's been keeping me from getting to sleep at night. I think I've devised a way to deal with it though -- window tint the display!

Re:Baby Blues. (1)

bill_mcgonigle (4333) | more than 5 years ago | (#25870177)

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 a red lightbulb in the kids' nightlight doesn't cost much.

Re:Baby Blues. (-1, Redundant)

Anonymous Coward | more than 5 years ago | (#25868315)

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?

Maybe I'm all wrong and there is something about blue light that stimulates us humans the wrong way.

Re:Baby Blues. (1)

arielCo (995647) | more than 5 years ago | (#25868357)

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)

Re:Baby Blues. (1)

basicio (1316109) | more than 5 years ago | (#25868501)

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'.

Re:Baby Blues. (1)

toddestan (632714) | more than 5 years ago | (#25869377)

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?

Re:Baby Blues. (1)

basicio (1316109) | more than 5 years ago | (#25870093)

Because blue is a different wavelength of light, which appears a lot more intense to our eyes.

Re:Baby Blues. (0)

Anonymous Coward | more than 5 years ago | (#25868577)

What was wrong with the cheap red leds? I am staring at two bright blue leds on my new computer, they are quite distracting.

Re:Baby Blues. (1)

rrohbeck (944847) | more than 5 years ago | (#25869957)

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.

Re:Baby Blues. (0)

Anonymous Coward | more than 5 years ago | (#25870779)

Really? I love them.

But that's just because I like the color blue.

Re:Baby Blues. (1)

my $anity 0 (917519) | more than 5 years ago | (#25867759)

They are still a few times more expensive to produce than the red ones. I guess they just look that much cooler? Also, we're talking about $.25 vs $.10, if there's one LED on the product, that's not a huge difference.

Re:Baby Blues. (1)

NeilTheStupidHead (963719) | more than 5 years ago | (#25867911)

Blue LEDs have been around since the 70s but not common until the 90s. A couple Japanese researchers in the 80s developed a new method for growing GaN crystals which made blue LEDs brighter and less expensive.

Re:Baby Blues. (3, Informative)

MidnightBrewer (97195) | more than 5 years ago | (#25869747)

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... (1)

djupedal (584558) | more than 5 years ago | (#25867503)

'A History of Light and Lighting' [mts.net] (4.5 Billion BC to 2005...) makes no mention of Mr. Holonyak...perhaps someone needs to build a fire under Mr. Williams.

Good video, small flaw. (3, Informative)

colinmc151 (714382) | more than 5 years ago | (#25867943)

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?

Re:Good video, small flaw. (1)

Muad'Dave (255648) | more than 5 years ago | (#25872345)

I don't know if the crystals are large enough, but most DIY stores carry carborundum grinding media. You can get some pretty good-sized chunks on a rotary sanding pad. Plus, there are mineral [rocksandminerals.com] and radio [xtalman.com] shops online.

Re:Good video, small flaw. (1)

rasputin465 (1032646) | more than 5 years ago | (#25873093)

In Imperial Russia, Czar makes diode out of YOU!

Silicon, not Silicone (3, Informative)

phage434 (824439) | more than 5 years ago | (#25868121)

Can't anyone keep the difference between silicon and silicone straight? Silicon: element, component of semiconductors (and some blue LEDs made from silicon carbide); Silicone: compound, used for breast implants

Re:Silicon, not Silicone (0)

maird (699535) | more than 5 years ago | (#25868215)

This being slashdot, the error is probably just wishful thinking!

Re:Silicon, not Silicone (0)

Anonymous Coward | more than 5 years ago | (#25869953)

It seems some of the folks involved with Make are greater experts in self-promotion than in technology.

Re:Silicon, not Silicone (1)

Hal_Porter (817932) | more than 5 years ago | (#25870185)

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.

Re:Silicon, not Silicone (1)

rubycodez (864176) | more than 5 years ago | (#25870333)

silicone is not a single compound, there are many different silicones which are polymers containing silicon.

Silicon carbide tools as LED (0)

Anonymous Coward | more than 5 years ago | (#25868265)

Has anyone experimented with a SiC coated tool as an LED? SiC coated tools are easier to find than SiC crystal.

Nice to be reminded! (1)

javelinco (652113) | more than 5 years ago | (#25868481)

It's nice to be reminded that making shows like these actually take some talent, experience and skill. Decent programs require actors who can deliver the lines convincingly (and sympathetically), script writers who understand the difference between first and third person perspective, and editors that can figure out how to make the different camera angles show us what's being talked about, instead of what's happening somewhere else.

What am I saying? Production values on this are just bad enough, it reminds me that even the crappy shows on television have SOME work put into them.

Thanks!

Risky Business (2, Insightful)

arachnoid (873176) | more than 5 years ago | (#25868693)

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/temperature relationship contradicts naive assumptions about electrical conductors.

To say this concisely, unless you have an unlimited semiconductor budget, "boys and girls, don't try this at home!"

Re:Risky Business (1)

nwf (25607) | more than 5 years ago | (#25868777)

I read that you should consider the internal resistance of the battery, which as I recall, was rather high in those coin-size batteries.

Re:Risky Business (1)

EkriirkE (1075937) | more than 5 years ago | (#25868985)

The only time I've ever had an LED go out on me without a resistor was when I was little and put one on a 9V.

Re:Risky Business (1)

MidnightBrewer (97195) | more than 5 years ago | (#25869749)

If you finish watching the movie, he actually goes on to say exactly that, and shows how to properly wire it with a resistor.

Re:Risky Business (1)

rdnetto (955205) | more than 5 years ago | (#25870133)

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.

Re:Risky Business (1)

mspohr (589790) | more than 5 years ago | (#25871065)

It's actually very safe to put a blue or white LED directly across a 3 volt battery. If you look at a graph of these diodes voltage versus light output, it's fairly linear in the area of 3 volts. The voltage drop across the diode is 3 volts so you don't need a resistor. It's not until you get above 4 volts that you get into the smoke generation range.

Re:Risky Business (1)

Dahan (130247) | more than 5 years ago | (#25871111)

The Photon Micro-Light [laughingrabbitinc.com] series of keychain LED flashlights have the LED connected straight to a lithium coin cell battery or two. Mine uses a pair of CR2016s, and has worked fine for years. You need to take into consideration the resistance of the battery.

Re:Risky Business (1)

Alioth (221270) | more than 5 years ago | (#25871219)

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 you want, and they will provide that current and let the voltage arrive at whatever it needs to be for that current to flow.

He's no James Burke (3, Insightful)

tkohler (806572) | more than 5 years ago | (#25870395)

If by "Connections-like" you mean appeals to nerds and involves history of technology, fine, but that is where the similarity ends. That being said, this was worth watching. The Silicon Carbide trick was cool.

Philips Lighting and LED's (1)

Rogue Pat (749565) | more than 5 years ago | (#25870715)

Back in the day, Philips had the slogan "Let's make things better" [wikipedia.org] .
However, some of my friends working at the Lighting Division changed that to "LED's make things better" :-)

Connections-like? How? (2, Informative)

catmistake (814204) | more than 5 years ago | (#25870761)

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.

New Pixar movie? (0)

Anonymous Coward | more than 5 years ago | (#25871975)

Can we rename it to 'LED-E'?

And in the opening credits, instead of the bouncing lamp dude, we'd have an LED-E himself.

Go back to the real beginning, please. (1)

SlideRuleGuy (987445) | more than 5 years ago | (#25872595)

So they didn't go back to the real beginning, which was the publishing by H. J. Round of the discovery that a silicon crystal would emit light when a current was passed through it? The credit for first discovery needs to go to an Englishman, not a Soviet... http://en.wikipedia.org/wiki/H._J._Round/ [wikipedia.org]
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