Conservapedia - User contributions [en]

Talk:Transistor

2009-03-22T14:51:52Z

PMorgan: /* Images */ new section

Can someone please account for the discrepancy between the first statement in the article and and the entry from from Wikipedia?

"The first three patents for the field-effect transistor principle were registered in Germany in 1928 by physicist Julius Edgar Lilienfeld, but Lilienfeld published no research articles about his devices, and they were ignored by industry. In 1934 German physicist Dr. Oskar Heil patented another field-effect transistor. There is no direct evidence that these devices were built, but later work in the 1990s show that one of Lilienfeld's designs worked as described and gave substantial gain. Legal papers from the Bell Labs patent show that Shockley and Pearson had built operational versions from Lilienfeld's patents, yet they never referenced this work in any of their later research papers or historical articles. The Other Transistor, R. G. Arns"

--[[User:AvengingAngel|AvengingAngel]] 17:51, 27 April 2007 (EDT)

== Images ==

I've done the best I can to describe how an FET works. However, it's pretty difficult without a diagram! It will be even harder with BJTs without being able to point to an energy band diagram. [[User:PMorgan|PMorgan]] 10:51, 22 March 2009 (EDT)

Transistor

2009-03-22T14:45:17Z

PMorgan: /* Function */ Added a simple explanation of how an FET works. Need to add BJT description too

The '''transistor''' is a device used to switch electrical signals on and off, or to amplify them (make them larger). It was invented at Bell Labs in Murray Hill, [[New Jersey]], by scientists William Shockley, Walter Brattain, and John Bardeen from the University of Minnesota.

==Function==

Modern transistors are so small that designers make heavy use of [[quantum theory]]. However, this isn't important for everyday use of the devices and a simple explanation of transistors is given below. There are two basic types of transistor: field-effect transistors (FETs) and bipolar junction transistors (BJTs).

=== Field-effect transistors ===

A field effect transistor contains a thin strip of [[semiconductor]] called the "channel". A pair of metal contacts are put at either end of the channel, allowing it to be connected into a [[circuit]]. These contacts are called the "source" and the "drain". The rest of the channel is coated with an [[insulator]] to stop any unwanted currents from entering or leaving.

Finally, a third metal contact called the "gate" is placed on top of the insulator. When a battery is connected between the gate and source, the insulator stops current getting through. Instead, the electrons in the channel are all pushed away from the gate. In other words, they can only move through a very thin part of the channel, making it difficult for current to flow between the source and drain. The [[resistance]] of the channel therefore depends on the [[voltage]] at the gate. If a big enough voltage is placed on the gate, the electrons can be pushed completely out of the channel and no current can flow at all.

The first transistors were made of [[germanium]], but more modern devices are made of [[silicon]]. Some modern devices use [[silicon-germanium]] alloys or [[gallium arsenide]].

==History==

Brattain and Bardeen usually worked without much supervision, as Shockley worked mostly from home. Their mission was to create the first amplifier using semiconductors.

Bardeen and Brattain were a perfect partnership, as Bardeen was a brilliant theoretician and Brattain a genius at experiments.

In December 1947, Bardeen had the insight that electrons formed a barrier on the surface, and Brattain worked that insight into a point-contact transistor. It used strips of gold foil on a plastic triangle, held in contact by a slab of germanium.

Shockley improved it to become the junction (sandwich) transistor. He mostly built it in a hotel room in Chicago. Once perfected, this was more durable than the point-contact transistor, and far easier to make. Upon this the semiconductor industry was built.

Bell Labs announced the invention to the public on June 30, 1948. Bell Labs engineer John Pierce gave it the name "transistor", a combination of "trans-resistance" with the names like thermistors.

Bardeen, Brattain, and Shockley made very little money from their invention. Others, like Gordon Moore and Robert Noyce in founding Intel, made a fortune. This was true even though Shockley himself saw the potential and started the company upon which Silicon Valley was based.

Japanese engineers like Masaru Ibuka and Akio Morita, who founded Sony Link title, were successful in improving the manufacturing of transistors.

==Significance==
Transistors created a revolution in [[electronics]].

Prior to the transistor, electronics relied on vacuum tubes. Vacuum tubes made possible very sophisticated electronics, including broadcast radio and television as we know them, radar, and the first electronic computers.

But vacuum tubes are large, expensive, power-hungry, and unreliable. Vacuum tubes use filaments like light bulbs. A typical tube consumes as much power as a ten or twenty-watt bulb. When turned on, tubes need many minutes to "warm up" and stabilize. During this time, radios do not hold their tuning and "drift" away from stations.

Like light bulbs, vacuum tubes have a short life. Eventually the filament burns out and the tube needs to be replaced.

In a home radio with six tubes, tube failure was only a nuisance. In an electronic computer—like the 17,468-tube ENIAC—it was disastrous, because with that many tubes some would always be failing.

The telephone company was concerned with tubes as well. Telephone signals cannot travel thousands of miles under the sea without amplification. Built into the cable every few miles were ''repeaters,'' electronic amplifiers to keep boosting and restoring signal strength. It is not easy to replace a tube when it fails in a cable on the sea floor.

And the military, which was starting to use electronics, was concerned because tubes are made of glass and are fragile, unable to withstand G-forces and vibration.

The transistor ushered in the "solid-state revolution," and another revolution called "miniaturization." Compared to tubes, transistors were at least a hundred times smaller, used a hundred times less power, and were extremely stable and reliable. At first, the transistor changed things in small ways. The book-sized portable radios that used small tubes were displaced by pocket-sized "transistor radios." Over time, transistors completely reshaped the way in which electronics could be used and the things that could be done with it.

A computer made out of transistors did not require continuous component replacement, and because of the stability of transistors it could be turned on and just start working properly within seconds. Transistorized circuits could withstand military conditions, in missiles for example, making electronic guidance systems much more feasible.

Originally "miniaturization" simply meant replacing light-bulb-sized tubes with jelly-bean-sized transistors. But a second breakthrough occurred in the 1960s, when engineers realized that the same technology used to create a single transistor on a semiconductor wafer could be used to create many interconnected transistors. Over time, engineers learned to put dozens, hundreds, thousand, and eventually millions of transistors onto a single chip, launching the "digital revolution."

[[Category:Technology]]

Transistor

2009-03-22T13:44:26Z

PMorgan: We need to state clearly what a transistor actually is first!

The '''transistor''' is a device used to switch electrical signals on and off, or to amplify them (make them larger). It was invented at Bell Labs in Murray Hill, [[New Jersey]], by scientists William Shockley, Walter Brattain, and John Bardeen from the University of Minnesota.

==Function==

There are two basic types of transistors, field effect transistors, which use an electric field to control how conductive a channel of semiconductor is, and bipolar junction transistors which work by modifying the level of electric charge in certain semiconductors.

==History==

Brattain and Bardeen usually worked without much supervision, as Shockley worked mostly from home. Their mission was to create the first amplifier using semiconductors.

Bardeen and Brattain were a perfect partnership, as Bardeen was a brilliant theoretician and Brattain a genius at experiments.

In December 1947, Bardeen had the insight that electrons formed a barrier on the surface, and Brattain worked that insight into a point-contact transistor. It used strips of gold foil on a plastic triangle, held in contact by a slab of germanium.

Shockley improved it to become the junction (sandwich) transistor. He mostly built it in a hotel room in Chicago. Once perfected, this was more durable than the point-contact transistor, and far easier to make. Upon this the semiconductor industry was built.

Bell Labs announced the invention to the public on June 30, 1948. Bell Labs engineer John Pierce gave it the name "transistor", a combination of "trans-resistance" with the names like thermistors.

Bardeen, Brattain, and Shockley made very little money from their invention. Others, like Gordon Moore and Robert Noyce in founding Intel, made a fortune. This was true even though Shockley himself saw the potential and started the company upon which Silicon Valley was based.

Japanese engineers like Masaru Ibuka and Akio Morita, who founded Sony Link title, were successful in improving the manufacturing of transistors.

==Significance==
Transistors created a revolution in [[electronics]].

Prior to the transistor, electronics relied on vacuum tubes. Vacuum tubes made possible very sophisticated electronics, including broadcast radio and television as we know them, radar, and the first electronic computers.

But vacuum tubes are large, expensive, power-hungry, and unreliable. Vacuum tubes use filaments like light bulbs. A typical tube consumes as much power as a ten or twenty-watt bulb. When turned on, tubes need many minutes to "warm up" and stabilize. During this time, radios do not hold their tuning and "drift" away from stations.

Like light bulbs, vacuum tubes have a short life. Eventually the filament burns out and the tube needs to be replaced.

In a home radio with six tubes, tube failure was only a nuisance. In an electronic computer—like the 17,468-tube ENIAC—it was disastrous, because with that many tubes some would always be failing.

The telephone company was concerned with tubes as well. Telephone signals cannot travel thousands of miles under the sea without amplification. Built into the cable every few miles were ''repeaters,'' electronic amplifiers to keep boosting and restoring signal strength. It is not easy to replace a tube when it fails in a cable on the sea floor.

And the military, which was starting to use electronics, was concerned because tubes are made of glass and are fragile, unable to withstand G-forces and vibration.

The transistor ushered in the "solid-state revolution," and another revolution called "miniaturization." Compared to tubes, transistors were at least a hundred times smaller, used a hundred times less power, and were extremely stable and reliable. At first, the transistor changed things in small ways. The book-sized portable radios that used small tubes were displaced by pocket-sized "transistor radios." Over time, transistors completely reshaped the way in which electronics could be used and the things that could be done with it.

A computer made out of transistors did not require continuous component replacement, and because of the stability of transistors it could be turned on and just start working properly within seconds. Transistorized circuits could withstand military conditions, in missiles for example, making electronic guidance systems much more feasible.

Originally "miniaturization" simply meant replacing light-bulb-sized tubes with jelly-bean-sized transistors. But a second breakthrough occurred in the 1960s, when engineers realized that the same technology used to create a single transistor on a semiconductor wafer could be used to create many interconnected transistors. Over time, engineers learned to put dozens, hundreds, thousand, and eventually millions of transistors onto a single chip, launching the "digital revolution."

[[Category:Technology]]

Talk:Quantum well

2009-03-21T12:33:12Z

PMorgan: tried to clear it up

Can you explain the relation between energy levels and colors of light? (And please spell [[color]] without the British 'u'.) --[[User:Ed Poor|Ed Poor]] [[User talk:Ed Poor|Talk]] 11:15, 20 March 2009 (EDT)
: An "energy level" just means "a particular amount of [[energy]]", nothing more. I've tried to clear that up. I've also really broken the description down into tiny bite-sized pieces. Is it OK to become an article again yet? [[User:PMorgan|PMorgan]] 08:33, 21 March 2009 (EDT)

Quantum well

2009-03-21T12:32:13Z

PMorgan: More improvements. Made description much clearer... broke things down into tiny pieces!

A '''quantum well''' is a device for storing [[electron]]s or other charged particles. They are used in many different types of modern technology, including computers, lasers and solar panels.

== Trapped particles ==
Imagine a ball rolling into the [[Grand Canyon]], it will fall to the bottom and cannot get back out unless a lot of energy is given to it (for example, someone at the bottom of the well could fire it out of a cannon!). A '''quantum well''' works in a very similar way. Electrical forces keep charged particles (such as [[electron]]s) inside the well, just like [[gravity]] keeps a ball inside the Grand Canyon.

A second important difference is that quantum wells are very small (about 1000th of the width of a human hair). At these scales, [[quantum mechanics|quantum effects]] come into play. This means that the electron may only have certain, fixed amounts of electrical [[energy]]. Think of this as being like standing on a ladder - you can only stand on the rungs, not the gaps in-between.

When the electron moves up its ladder of permitted energies, it must absorb exactly the right amount of energy to do so. This is like putting enough effort into raising your leg to reach the next rung of the ladder without overstepping it. Similarly, when the electron moves down its ladder of permitted energies, it gives out a burst of energy of exactly the right size.

== Packets of light ==
[[Einstein]] won a [[Nobel prize]] by showing that the energy in a beam of light is actually contained in lots of small packets called [[photon]]s, rather than being spread out evenly in the beam. The energy stored in each photon depends on the color ([[frequency]]) of the light. Red or [[infrared]] light has its energy stored in lots of low energy photons, while blue or [[ultraviolet]] light has its energy stored in a smaller number of high energy photons.

== Putting it all together... ==
We know now that electrons absorb or emit fixed sized bursts of energy when they move up or down inside a quantum well. We also know that each color of light is made of packets of energy of a fixed size. If we shine light on a quantum well, then interesting things happen... If the photons in the beam of light contain just the right amount of energy, they can "push" electrons up to higher "rungs" on their ladder of energies! In other words, the quantum well turns light of particular colors into electricity of particular [[voltage]]s. Scientists and engineers have made many different kinds of light-detecting devices from quantum wells, including solar panels and some modern digital cameras.

Quantum wells work the other way round too. If we attach a battery to the quantum well, then we give lots of electrical energy to the electrons and they are able to "climb" high up their ladder of energies. Over time, they drop down the ladder and release bursts of energy of fixed sizes. This energy is stored inside photons, meaning that a beam of light comes out of the quantum well. Again, many useful devices have been made, including [[laser]]s and [[LED]]s.

Talk:Photon

2009-03-15T23:37:50Z

PMorgan: clearer explanation?

I did a major edit on the Photon page. As Richard Feynman himself said in his lectures to the public on QED, "photons are particles". The explanation of why they sometimes behave like waves should also be inserted into the quantum mechanics article, as it is a general feature of the theory.--[[User:Lemonpeel|Lemonpeel]] 13:19, 8 July 2008 (EDT)

:Can you explain how light can be both a wave and a particle? --[[User:Ed Poor|Ed Poor]] [[User talk:Ed Poor|Talk]] 13:43, 8 July 2008 (EDT)

It is not both. It is a particle. However, due to interference possibilities of amplitudes in quantum mechanics, it sometimes behaves like a wave. I am currently trying to explain this in the quantum mechanics page.--[[User:Lemonpeel|Lemonpeel]] 13:58, 8 July 2008 (EDT)

Not sure how to make the first few sentences more jargon-free. There's no elementary way to explain what integer spin is--it's just one of those things. Maybe you can describe bosons as mediators of forces between matter particles. Still if someone is actually looking up photon, they should see that it's a massless particle with spin 1 somewhere on the page.--[[User:Lemonpeel|Lemonpeel]] 14:06, 8 July 2008 (EDT)

:I seem to remember that Stephen Hawking gave a very nice analogy for the wave-particle duality in one of his books. It went something like this: A mediaeval monk travelled from England to Africa and saw a [[rhinoceros]] for the first time. When he came back, he described his observations to his fellow monks. He said, "when I looked at the front of the animal, it had a single horn". "You mean it was a unicorn?" asked the abbot. "Almost," he said, "but when I touched its skin, it felt like thick, scaly armour". "So it's a dragon?" asked the abbot.

:To summarise: the travelling monk described some observations and the abbot came up with a couple of theories. The first theory was that the rhinoceros was a unicorn based on the observation that it had a horn. The second theory was that the rhinoceros was a dragon, based on the observation that it had scaly skin. Each theory was very good at describing certain types of observation, but not very good for others. The important point is that the abbot didn't know the "true" nature of the rhinoceros, but he found some nice ways to describe its characteristics. Neither unicorns nor dragons walk among us, but they were used by the abbot as models to help him understand the characteristics of the rhinoceros.

:Scientists can only base their theories on observations. Some observations, like the [[photoelectric effect]] show that light behaves like a stream of classical particles. Other observations, like [[interference]] show that it behaves like a classical wave.
Scientists don't know the "true" nature of light, but they have found some nice ways of describing its behaviour. Just like the dragon and the unicorn, classical waves and particles don't really exist but they are very useful models to help us understand the characteristics of light.

:I hope that explanation helps! [[User:PMorgan|PMorgan]] 19:37, 15 March 2009 (EDT)

User talk:PMorgan

2009-03-14T14:03:06Z

PMorgan: rewritten

I moved your article out of mainspace, because it's not clear. Please rewrite it, with a 10 or 14 year old child in mind. --[[User:Ed Poor|Ed Poor]] [[User talk:Ed Poor|Talk]] 08:22, 14 March 2009 (EDT)
:Oops, I didn't realise that we were aiming for that sort of age group - I'm used to teaching it to 18-21 year olds, but I'll try to tone it down!

::Articles like this just need an introduction which assumes little or no previous knowledge. I know what [[potential energy]] is, because I studied physics - with the equations and everything. But most of our readers will have learned "science" as a collection of "facts". I doubt that one person in 100 has the foggiest idea of what potential energy is.

::Meet the reader where he is, and then bring him on an amazing journey to where you live! :-) --[[User:Ed Poor|Ed Poor]] [[User talk:Ed Poor|Talk]] 09:02, 14 March 2009 (EDT)
:::OK, I've tried to rewrite it. How does it look?

Quantum well

2009-03-14T14:01:13Z

PMorgan: rewritten to make things clearer

User talk:PMorgan

2009-03-14T12:28:54Z

PMorgan: I'll try!

Quantum well

2009-03-14T12:17:08Z

PMorgan: Created the article - anyone want to help?

A '''quantum well''' is a narrow dip in [[potential energy]], which can be used to store [[electron]]s or other charged particles. A quantum well could be created by sandwiching two materials together, such as a thin sheet of metal between two blocks of rubber. An infinitely deep quantum well would have a voltage of 0V in the middle, and infinity in the barriers.

Quantum wells are used in many modern devices, including lasers, light detectors, transistors (the computer you are using right now contains around a billion!). Some of the newest LCD computer monitors use quantum wells to give ultra-fast switching in their backlighting.

Sputnik (satellite)

2009-03-14T11:54:11Z

PMorgan: It was the size of a beach ball (over half a meter in diameter) i.e. much bigger than a basketball! I added NASA reference

'''Sputnik''' was launched in 1957 by the [[Soviet Union]] as the first spacecraft to carry a living being, a dog, into outer space.

*''Sputnik I'', launched [[October]] 4, 1957, carried an artificial satellite into orbit. It caused some concern in the [[USA]], that the Soviet Union were the first to launch a satellite into orbit. ''Sputnik I'' was about the size of a beach ball (58cm or 22.8inches in diameter),<ref>[http://history.nasa.gov/sputnik/ NASA's files on Sputnik]</ref> had antennas sticking out of it, contained a beeping radio transmitter<ref>CNN: Cold War Vol. 3 - Documentary</ref>, and weighed only 183 pounds.<ref>http://history.nasa.gov/sputnik/</ref> This success started the [[Space Race]] between the USSR and the USA.

*''Sputnik II'' carried a dog named Laika ([[Russian]]: Лайка) into space on November 3, 1957. Laika was originally a stray, and she died a while after the launch.

== See Also ==
*[http://history.nasa.gov/sputnik/ NASA's files on Sputnik]

==References==
<references />
[[Category:Space Exploration]]
[[Category:Space Race]]
[[Category:Cold War]]