Nobody would ever seriously run a production LED system like this. Typical forward voltage of white LEDs is around 3V. Supplying rectified AC would waste 97% of the energy on US 110V, thus making it less efficient that a halogen bulb and producing lots of heat in the resistor.
The things contain a switch mode power supply, like just about every small mains powered device nowadays. The SMPS converts input to a current output for LEDs, which is what they need for best efficiency. It does this on both halves of the AC cycle. This added complexity contributes to the cost, but not as much as you might think.
Early LED bulbs that ran off cheap transformers used for SELV lighting used series resistors, but the current is very variable and they are, basically, crap. They got away with it because big arrays of cheap LEDs were used. A long term solution really needs not more than two or three high power LEDs in an envelope, because this helps to drive down cost. But this requires an advanced power supply.
Thanks for responding. This could do with some mod points but I can't mod and post...so I'll respond. It's interesting to think about what is happening here. It's possibly unhelpful to refer in the same sentence to "current" and "electrons" but I know what you mean, though I would rephrase it a little to help my own understanding. The "current" did not cause the carbon atom to give off electrons; rather, the potential difference enabled some electrons to pass along the carbon chain until they left the tip, and the path of the emerging electrons was probabilitistically interfered with in a way that reflected the solution of the Schroedinger wave equation for the outer electrons of the end atom. That's a very interesting experiment. The benefit of using carbon atoms in a molecule is that the bond angle presumably locks the orientation of the P orbitals sufficiently to enable the experiment. So for many atoms it simply wouldn't work, and what we are seeing here is not an image per se but something more like the result of the Rutherford/Geiger/Marsden experiment. It looks like a significant experiment, but the summary is quite wrong as to what is being shown.
Why? Because the "orbitals" are actually solutions of the Schroedinger Wave Equation. They are images or a probability distribution in abstract space. Electrons are not clouds or points, they are things we don't really understand but describe by means of quantum mechanics. So I am deeply suspicious of the picture, because there is no physical object of that shape to image.
Although I was making a sarcastic point - it's a bunfight for lawyers - this will inevitably result in litigation. It is potentially very anti-competitive. Now, what do you want? A strong European Competition Commission that takes consumer issues seriously and is prepared to take on multinationals who want monopolies, or a weak ECC and the sort of high prices and restrictive contracts that are the norm in the US?
And who do you want in court? Elderly lawyers who don't understand this newfangled mobile phone stuff, or specialists who have studied the subject, worked with both providers and Government departments, and understand the issues?
Let me reiterate:not only are you nasty, you are clearly totally unqualified to comment on the subject.
You might also like to consider, insofar as you are capable, that perhaps if companies were not so monopolistic and their bosses - who get paid far more than even the richest lawyers - not so greedy, the need for corporate lawyers would rapidly dry up.
I think the submitter means "disagreed", or "argued" not "debated". I expect that in the early stages quite a lot of people debated the subject, but when the results become clear they stopped arguing and there was a general agreement
Yes, I know it's pedantry, but some of us like to live in a world where different words mean different things that make a useful distinction. And now, please, do get off my lawn before my dog comes and pees on your shoes.
Replying to myself (sorry) I note how quickly my original comment was modded down as "redundant" despite not, in fact, being redundant. It looks to me like the Dianetics Foundation (excuse the term, but I'm sensitive about using the word "church" in this context)slashdot-watcher ran out of mod points rather quickly.
I would defend my use of the term "Pyramid scheme". Pyramid schemes are not illegal. It's Ponzi schemes which are illegal, i.e. those which promise impossible returns by using the assets of low-level entrants to pay a return to high-level members. Most businesses nowadays are in fact pyramid schemes of one sort or another, e.g. Ford manufacture cars but appoint distributors who appoint authorised dealerships, and successful individuals may move up the chain. As I understand it, the DF is a classic pyramid scheme in which recruits may progress to higher levels, at which they in turn recruit to levels below them. The main and obvious difference between, say, the DF and the Catholic Church is that in the Church you can become Pope while never having contributed money to the cause, while I do not believe that is true of the DF
I don't see why Scientology is interested in the matter. It's not as if they're a religion. They haven't even suggested the protection of pyramid schemes.
Everything you write can be said of physicists and engineers (and indeed many other professions.) That's why this is bullshit. Musicians are not a special breed. Recording companies are simply trying to do what no other business has ever done, spend ridiculous amounts of money not to spread the word about good music, but to restrict what gets sold to a limited few by ensuring only they get publicity. They make their money by throttling the market, not widening it. That's why it's so expensive.
Music in the past was about live performance. This required a lot of musicians. The recording companies then discovered they could change it to an industry that depended almost entirely on recordings, thus killing off a lot of the demand for live performance. Did they compensate those out of work musicians? No. So why should they be paid now? How is their case different?
In fact, as you should know, everything in the way of computer hardware can be constructed from either nor or nand gates. These have no concept of addition, only two logical operations (or/and plus negation. Although boolean algebra is conventionally included in mathematics, it is actually the core discovery of computer science. Building on that, every arithmetic operation can be carried out by a suitable combination of logical functions along with a storage element - which can be physically implemented using logic devices, but is not conceptually so implemented.
You cannot build a computer using nothing but addition.
Most modern computers (by quantity) are basically communications devices. Although we have converted the processes of communication to mathematical operations, this is to fit in with the way a computer works. We manage to speak to one another without the use of mathematics. We do not see the function of a mobile phone or a netbook as being "to perform mathematical calculations".
Early data processing machines (like Hollerith card analysers) were designed to perform select and sort operations which they did using logical functions, but they did not do calculations. You wanted to know who in a brigade had a particular skill, you fed in the punched cards for the brigade, and the output stack delivered the ones whose holes coincided with the setup. Colossus was intended to do code breaking by high speed (for the time) data processing, but it did not do general purpose calculation. So yes, this is a meaningful distinction.
The original US tube-based computer (I forget the acronym) had about 5000 tubes, each of which had a MTTF of around 2-3000 hours. Many people thought that it would break down too often to be of any use. But the designers had realised that what kills tubes is turnon (when the filament carries more current because it is low resistance) causing filament damage and thermal shock damage to the envelope. If the tubes were warmed up slowly and then left on all the time, there would be an infant mortality phase but then the machine would get more reliable with time as the tubes got into the depths of the bathtub life curve.
Pedant note: although "all the time" or "always on" have more letters than "24x7", they are quicker to say and more meaningful. Why do we have this horrible cypher?
Alan Turing (genuflect three times) calculated that gin (i.e. 60% water/40% ethanol) was as good as mercury. But it wasn't "exotic" enough to be approved for use.
Sorry, it was the Poles obtained German Enigmas and took them to the UK. The news that the Germans relied on Enigma was important, but the main reason the British were able to beat Enigma was that the Germans were insufficiently careful in its use. When the system changed later in the war, the Royal Navy (NOT the USN, contrary to the lies of Hollywood) acquired a naval Enigma machine from a sinking German submarine. (They also captured a German weather boat at one point.)
It is simple fact that many cryptographic systems are uncrackable in the absence of all knowledge of how they work - but in the real world keys must be exchanged somehow, and encryption must always have a mechanism, and these are always potential vulnerabilities.
It's in one of the HSE discussion documents. There's a lot of other information there, but this one caught my eye. I didn't record the link at the time, I'm afraid, but the alphas from uranium have practically no penetrating power, and when the uranium is in clad pellets nothing will come out.
This is the most intelligent comment on this thread so far, why it is posted as AC I cannot imagine. It reminds me of a brilliant comment on the assembly of nuclear fuel rods: that they are so nonradioactive that they can be assembled by hand. The operators wear gloves, not to protect them from the fuel, but to protect the fuel from their fingers.
One screwdriver is usually all that's needed. Extract discs, rub firmly with fine glasspaper, break or bend with lump hammer, label and store in drawer for future reference. I find it takes about 5 minutes. Your co-workers may appreciate the drive magnets to amuse their kids.
Gandolf should just have handed the ring over one of the eagles, eagle flies off to Mt. Doom and disposes of the Preciouss while the Nazgul are looking for Frodo, nearly three volumes of tedium no longer need to be read.
Surely this decision to plead guilty has opened the floodgates. If taking money off the gullible and statistically challenged is racketeering, now is the time to invest in companies that build prisons in the US.
After all, Madoff was operating a Ponzi scheme. This guy told the gamblers the truth about what he was doing, and they gave him money voluntarily.
The US medical industry already represents 16% of the GNP and is higher than any other developed country, including the ones that have "socialist" health systems. Under your present system costs have already "skyrocketed". In the US, healthcare is already rationed by (a) ability to pay and (b) the attempts of insurance companies to maximise shareholder return. In Europe, we just happen to think that our health systems are best managed by people who answer to the electorate rather than people who answer to shareholders. I think that's called "democracy" rather than "socialism".
And encouraging the Australians every step of the way. (NZ is trying to expand its IT economy, this kind of application of projectile to pedal extremity is just the kind of thing they need.)
I've done a more extensive post below, but basically the broad brush explanation of why the sky is blue is not university level and can be explained with a piece of broken glass, a flashlight, a glass of water and a few drops of milk. It can be explained to someone with a reading age of 10 (I did an experimental practical-based class in basic science back in the early 70s, with test subjects aged 8-10, so I think I know something about this.) The mistake many people make on these threads is to assume that explanation stops at a certain level, and that is the "why". It does not. Explanation goes down many levels, and needs to be parked at a level suitable for the person being explained to. The ignorance of your wife's family is a criticism of poor science curriculum development.
A lot of people above are posting about "Why is the sky blue" being a hard question, Rayleigh scattering, etc. etc. But this is to miss the context, which is telling children. The level of an explanation depends on the ability of the explained-to person to understand.
From this point of view, all that is needed is to be able to explain light from the sun is made up of all colors (no need to explain wavelengths) - which you can demonstrate with a bit of broken glass, no need for an official prism - and are then most of the way to the rainbow explanation - and that the blue light from the sun is spread out more by the atmosphere. You can demonstrate scattering simply by putting a little milk in a glass of water and shining a flashlight through it. This is a level of explanation suitable for a child under, say, 13, and already introduces a number of ideas about optics.
As for where babies come from, even quite small children are quite safe with the idea that babies grow inside their mothers. Rural children can hardly avoid knowing this by the age of 3 or so. They need reassurance that it won't happen to them, yet, and they need a gradual increase of detail until they reach puberty. But they don't need to know about DNA, cell fission, fertilisation and so on in order to understand what causes pregnancy and how to avoid it until it's actually wanted.
Personally, I blame not so much the dumbing down as the increasing formalism of science teaching. The criticism of science teaching in Brazil made by Richard Feynmann is now valid in much of the West today. We actually need to teach ideas with simpler, more familiar equipment rather than the special manufactured experiments in school labs, otherwise how can people see the relevance? The example above, of someone suddenly realising that mayonnaise is an emulsion, is a good one.
Back in the 17th century he suggested sending encrypted messages by various nonobvious means, for instance firing a gun at intervals that represented a binary code, or making prick marks through certain letters in a book. In effect, back to steganography.
Steganography was very big at the time. For instance, some people believe that Wm Shakespere was involved in the King James Bible but could not be credited because, as an actor, he was not respectable. Find the King James Version, find psalm 46, find 46th words from the start and the end. The nice thing is it could be pure coincidence, which is a core principle of staganography.
Slashdot Mirror
The things contain a switch mode power supply, like just about every small mains powered device nowadays. The SMPS converts input to a current output for LEDs, which is what they need for best efficiency. It does this on both halves of the AC cycle. This added complexity contributes to the cost, but not as much as you might think.
Early LED bulbs that ran off cheap transformers used for SELV lighting used series resistors, but the current is very variable and they are, basically, crap. They got away with it because big arrays of cheap LEDs were used. A long term solution really needs not more than two or three high power LEDs in an envelope, because this helps to drive down cost. But this requires an advanced power supply.
Thanks for responding. This could do with some mod points but I can't mod and post...so I'll respond. It's interesting to think about what is happening here. It's possibly unhelpful to refer in the same sentence to "current" and "electrons" but I know what you mean, though I would rephrase it a little to help my own understanding. The "current" did not cause the carbon atom to give off electrons; rather, the potential difference enabled some electrons to pass along the carbon chain until they left the tip, and the path of the emerging electrons was probabilitistically interfered with in a way that reflected the solution of the Schroedinger wave equation for the outer electrons of the end atom. That's a very interesting experiment. The benefit of using carbon atoms in a molecule is that the bond angle presumably locks the orientation of the P orbitals sufficiently to enable the experiment. So for many atoms it simply wouldn't work, and what we are seeing here is not an image per se but something more like the result of the Rutherford/Geiger/Marsden experiment. It looks like a significant experiment, but the summary is quite wrong as to what is being shown.
Why? Because the "orbitals" are actually solutions of the Schroedinger Wave Equation. They are images or a probability distribution in abstract space. Electrons are not clouds or points, they are things we don't really understand but describe by means of quantum mechanics. So I am deeply suspicious of the picture, because there is no physical object of that shape to image.
And who do you want in court? Elderly lawyers who don't understand this newfangled mobile phone stuff, or specialists who have studied the subject, worked with both providers and Government departments, and understand the issues?
Let me reiterate:not only are you nasty, you are clearly totally unqualified to comment on the subject.
You might also like to consider, insofar as you are capable, that perhaps if companies were not so monopolistic and their bosses - who get paid far more than even the richest lawyers - not so greedy, the need for corporate lawyers would rapidly dry up.
This merger makes me very happy indeed. One of my kids is a lawyer specialising in telecoms competition issues. Recession? What recession?
Yes, I know it's pedantry, but some of us like to live in a world where different words mean different things that make a useful distinction. And now, please, do get off my lawn before my dog comes and pees on your shoes.
I would defend my use of the term "Pyramid scheme". Pyramid schemes are not illegal. It's Ponzi schemes which are illegal, i.e. those which promise impossible returns by using the assets of low-level entrants to pay a return to high-level members. Most businesses nowadays are in fact pyramid schemes of one sort or another, e.g. Ford manufacture cars but appoint distributors who appoint authorised dealerships, and successful individuals may move up the chain. As I understand it, the DF is a classic pyramid scheme in which recruits may progress to higher levels, at which they in turn recruit to levels below them. The main and obvious difference between, say, the DF and the Catholic Church is that in the Church you can become Pope while never having contributed money to the cause, while I do not believe that is true of the DF
I don't see why Scientology is interested in the matter. It's not as if they're a religion. They haven't even suggested the protection of pyramid schemes.
Music in the past was about live performance. This required a lot of musicians. The recording companies then discovered they could change it to an industry that depended almost entirely on recordings, thus killing off a lot of the demand for live performance. Did they compensate those out of work musicians? No. So why should they be paid now? How is their case different?
You cannot build a computer using nothing but addition.
Early data processing machines (like Hollerith card analysers) were designed to perform select and sort operations which they did using logical functions, but they did not do calculations. You wanted to know who in a brigade had a particular skill, you fed in the punched cards for the brigade, and the output stack delivered the ones whose holes coincided with the setup. Colossus was intended to do code breaking by high speed (for the time) data processing, but it did not do general purpose calculation. So yes, this is a meaningful distinction.
Pedant note: although "all the time" or "always on" have more letters than "24x7", they are quicker to say and more meaningful. Why do we have this horrible cypher?
Alan Turing (genuflect three times) calculated that gin (i.e. 60% water/40% ethanol) was as good as mercury. But it wasn't "exotic" enough to be approved for use.
It is simple fact that many cryptographic systems are uncrackable in the absence of all knowledge of how they work - but in the real world keys must be exchanged somehow, and encryption must always have a mechanism, and these are always potential vulnerabilities.
It's in one of the HSE discussion documents. There's a lot of other information there, but this one caught my eye. I didn't record the link at the time, I'm afraid, but the alphas from uranium have practically no penetrating power, and when the uranium is in clad pellets nothing will come out.
This is the most intelligent comment on this thread so far, why it is posted as AC I cannot imagine. It reminds me of a brilliant comment on the assembly of nuclear fuel rods: that they are so nonradioactive that they can be assembled by hand. The operators wear gloves, not to protect them from the fuel, but to protect the fuel from their fingers.
One screwdriver is usually all that's needed. Extract discs, rub firmly with fine glasspaper, break or bend with lump hammer, label and store in drawer for future reference. I find it takes about 5 minutes. Your co-workers may appreciate the drive magnets to amuse their kids.
Gandolf should just have handed the ring over one of the eagles, eagle flies off to Mt. Doom and disposes of the Preciouss while the Nazgul are looking for Frodo, nearly three volumes of tedium no longer need to be read.
When I was at school we practically worshipped our English teacher because her husband had been a roadie for Deep Purple.
After all, Madoff was operating a Ponzi scheme. This guy told the gamblers the truth about what he was doing, and they gave him money voluntarily.
The US medical industry already represents 16% of the GNP and is higher than any other developed country, including the ones that have "socialist" health systems. Under your present system costs have already "skyrocketed". In the US, healthcare is already rationed by (a) ability to pay and (b) the attempts of insurance companies to maximise shareholder return. In Europe, we just happen to think that our health systems are best managed by people who answer to the electorate rather than people who answer to shareholders. I think that's called "democracy" rather than "socialism".
And encouraging the Australians every step of the way. (NZ is trying to expand its IT economy, this kind of application of projectile to pedal extremity is just the kind of thing they need.)
I've done a more extensive post below, but basically the broad brush explanation of why the sky is blue is not university level and can be explained with a piece of broken glass, a flashlight, a glass of water and a few drops of milk. It can be explained to someone with a reading age of 10 (I did an experimental practical-based class in basic science back in the early 70s, with test subjects aged 8-10, so I think I know something about this.) The mistake many people make on these threads is to assume that explanation stops at a certain level, and that is the "why". It does not. Explanation goes down many levels, and needs to be parked at a level suitable for the person being explained to. The ignorance of your wife's family is a criticism of poor science curriculum development.
From this point of view, all that is needed is to be able to explain light from the sun is made up of all colors (no need to explain wavelengths) - which you can demonstrate with a bit of broken glass, no need for an official prism - and are then most of the way to the rainbow explanation - and that the blue light from the sun is spread out more by the atmosphere. You can demonstrate scattering simply by putting a little milk in a glass of water and shining a flashlight through it. This is a level of explanation suitable for a child under, say, 13, and already introduces a number of ideas about optics.
As for where babies come from, even quite small children are quite safe with the idea that babies grow inside their mothers. Rural children can hardly avoid knowing this by the age of 3 or so. They need reassurance that it won't happen to them, yet, and they need a gradual increase of detail until they reach puberty. But they don't need to know about DNA, cell fission, fertilisation and so on in order to understand what causes pregnancy and how to avoid it until it's actually wanted.
Personally, I blame not so much the dumbing down as the increasing formalism of science teaching. The criticism of science teaching in Brazil made by Richard Feynmann is now valid in much of the West today. We actually need to teach ideas with simpler, more familiar equipment rather than the special manufactured experiments in school labs, otherwise how can people see the relevance? The example above, of someone suddenly realising that mayonnaise is an emulsion, is a good one.
Steganography was very big at the time. For instance, some people believe that Wm Shakespere was involved in the King James Bible but could not be credited because, as an actor, he was not respectable. Find the King James Version, find psalm 46, find 46th words from the start and the end. The nice thing is it could be pure coincidence, which is a core principle of staganography.