Monday, August 26, 2019

Crystal Fire #6

After World War II the people at Bell Labs could resume its focus on basic research and development. The middle chapters of Crystal Fire give many details about this period through the early 1950s. They learned many things about the electrical property of different elements, compounds, combinations, of solid state devices. They also encountered mysteries about these things that prompted further research. They also had to spend considerable time obtaining samples of materials absent undesired impurities or optimal amounts of desired impurities. Patents were filed and there were concerns about patents already in place, what exclusive rights the military might want, and what progress was being in other labs such as at Purdue University.

There were two types of transistors invented at Bell Labs during those years – the point contact invented by John Bardeen and Walter Brattain and the junction type spearheaded by William Shockley.

In June 1951 Bell Labs gave a press conference about transistors. The star of the show was the junction transistor. Perhaps its most remarkable feature was its extremely low power consumption, about one-millionth of conventional vacuum tubes. It also amplified signals with far greater efficiency than the point-contact transistor.

The point-contact transistor was still used in the Bell System. Practical use of it came earlier. It entered mass production at Western Electric (a subsidiary of AT&T), servicing complex switching equipment to permit direct dialing and bypassing traditional telephone operators.

But the point-contact transistor never made it to the commercial marketplace in a big way. Apart from transient usage in hearing aids and military equipment, the only important applications it ever found came in the Bell System. Other manufacturers were reluctant to put significant capital into its production, especially after the recent breakthrough by Shockley’s team. The future belonged to the junction transistor and its offspring.

Wednesday, August 21, 2019

Crystal Fire #5

Walter Brattain began working at Bell Labs in 1929. Mervin Kelly was a researcher at Bell Labs who became its director of research in 1936. He envisioned telephone switches being electronic rather than mechanical. William Shockley was Kelly’s first hire after a hiring freeze was lifted in 1936. Kelly hired Shockley for the latter’s knowledge of quantum mechanics. Shockley took Kelly’s vision as a guiding light. For the next several years, Bell Labs grew its research staff with specialists in quantum mechanics. In 1937 Clinton Davisson of Bell Labs won the Nobel Prize for his experiments that electrons behaved like waves.

Brattain and Joseph Becker studied the papers of Walter Shottky and Nevill Mott (neither at Bell Labs). The papers said that whenever a metal and a semiconductor come into contact, a double layer of charge crops up – positive on one side and negative on the other – because of the difference in work functions of the two materials. This leads to a kind of “hill” that electrons must surmount if they are to cruise from one side to the other. “Because this hill is asymmetric, with a steep cliff on the metal side and a shallow slope on the other, electrons move far more readily from semiconductor to metal than in the opposite direction." This finally provided a satisfactory explanation of rectification, which had mystified scientists for 65 years. Shockley, Brattain, and Becker attempted fabricating devices to make use of this effect. Not only was progress slow, it was interrupted with work on topics like radar, submarine detection, mines, and torpedoes due to World War II.

Friday, August 16, 2019

Crystal Fire #4

Bell Telephone Labs grew around the efforts of American Telephone & Telegraph to develop vacuum tubes for long distance communication. Through a variety of gimmicks, the Bell System enabled transmitting telephone calls over 1000 miles by 1900. Beyond that distance, transmission deteriorated. For transcontinental service to become a reality, the company needed a “repeater” device to replenish the electrical signals at points along the line. AT&T installed a transcontinental line by 1915. Repeaters in Salt Lake City, Omaha, and Pittsburgh boosted the electrical signals.

In the 1920s and 1930s the new discipline of quantum mechanics was used to discover the movement of electrons and the properties of conductors, insulators and semiconductors. New theories superseded older ones. Walter Brattain began work at Bell Labs in 1929. He and colleague Joseph Becker became interested in copper-oxide rectifiers. Copper-oxide belonged to a new class of substances called “semiconductors.” They had some unique properties different from both conductors and insulators. Unlike metals, the conductivity increases with increasing temperature. Copper-oxide rectifiers, dubbed varistors”, began to replace bulky vacuum diodes throughout the Bell system. The speed at which this happened was restrained at Bell Labs by a lack of physicists with enough understanding of quantum mechanics and a hiring freeze during the Great Depression.

Tuesday, August 13, 2019

Crystal Fire #3

Americans were latecomers to the quantum revolution. Europeans led the way in forming deeper and more fundamental insights about the quantum world. It was in the application of the new theoretical insights and experimental techniques that U.S. scientists excelled in the 1920s. They explored the internal structure and intrinsic properties of solids: color, hardness, conductivity, and so forth.

In the last quarter of the 19th century, physicists became fascinated with cathode-ray tubes. In 1895 Roentgen discovered X-rays – so-called because he didn’t know what they were. X-rays excited the imagination, but much mystery about them remained. Were they waves or particles? Physicists searched for zebra-striped interference patterns like visible light produced. But if X-rays had wavelengths a thousand times shorter than visible light, any suitable diffraction grating would need spacing a thousand times smaller, less than a billionth of a meter. Nobody knew how to make such a fine grating. In 1912 two of Roentgen’s students found a wreath-like pattern of brights spots against a dark background directing X-ray beams onto a crystal of copper sulfate. Other crystals produced similar patterns. Max von Laue thought the interference patterns were caused by a three-dimensional lattice of objects within the crystals. William Henry Bragg and his son extended von Laue’s insights. All three received a Nobel Prize for their work.

Scientists could then peer inside crystals, where the atoms appeared to be arranged in layers, like eggs stacked in crates.

Physicists began to recognize the conductivity of metals had something to do with the availability of electrons within them. An excellent conductor like copper has plenty of free electrons. Good insulators, like glass or wood, have essentially none.

Chapter 3 has more about other discoveries in physics, such as Rutherford’s discoveries of the inner structure of atoms and Schrรถedinger’s wave equation. I will skip the details to stick to the main story of the book and avoid possible errors trying to summarize it.

Practical-minded Americans like Walter Brattain had little interest in the airy philosophical debates such as occurred between Niels Bohr and Albert Einstein. They were busy applying the new quantum tools to their study of matter. Plenty of unsolved problems about the nature and structure of atoms, molecules, metals, and crystals awaited exploration with the new methods.

Sunday, August 11, 2019

Crystal Fire #2

A long strand of aluminum or copper wire tacked to the roof of a house or strung between trees served as an antenna to capture radio signals. Electrons in the wire oscillated back and forth as these waves passed, like corks bobbing on water. Another wire coiled around a cylinder provided a tuning device to select the specific radio frequency transmitted by a station and to eliminate unwanted signals. And a pair of earphones translated the tiny pulses of electric current back into the words or sounds that had been spoken or played into a microphone at the station.

A crystal detector converted the back-and-forth alternating current in the antenna and tuning circuit into one-way bursts of direct current required by the earphones. Exactly how crystals worked had been a mystery until the 1920s, despite their having been used. In 1874 Ferdinand Braun discovered that currents in crystals flowed more readily in one direction, and with a sharp wire tip pressed into a crystal face flowed in a single direction. This is called rectification.

Hearing about Marconi’s difficulties in sending signals long distances relying on a spark between two electrodes starting in the mid-1890s, Braun developed a new kind of sparkless transmitter, which eventually allowed transmitting voice and music, not mere Morse code.

Chapter 2 of Crystal Fire also gives personality and biographical sketches of Brattain, Bardeen, and Shockley.

Friday, August 9, 2019

Crystal Fire #1

Crystal Fire is a book about the invention of transistors, microchips, integrated circuits, and the birth of the information age.

On December 23, 1947 William Shockley arrived at his workplace, Bell Labs, eager for some news. Shockley was head of the solid-state physics group, and two people in his group had made an exciting discovery. The two were John Bardeen and Walter Brattain. Using little more than a slab of germanium, a thin plastic wedge, and a strip of gold foil, they had recently boosted an electrical signal almost a hundredfold. It was dubbed “transistor.” It was an archetypal moment, akin to 70 years earlier when Alexander Graham Bell said, “Mr. Watson, come here. I want you.”

Shockley had been seeking ways to fashion a solid-state device to replace the bulky, unreliable switches and amplifiers commonly used in phone equipment. By January, 1948 Shockley had figured out the important details of his own “junction” design – different from Bardeen’s and Brattain’s “point contact” design – which he believed would be more reliable and easier to mass-produce.

It took a couple more years to perfect the techniques to grow germanium crystals. It took a few more years to figure out how to improve and mass-produce the “junction” design to replace the “point contact” design well underway in manufacturing.

Bardeen departed Bell Labs in 1951. Shockley departed in 1955 for Silicon Valley to start a transistor-making company. They and Brattain met again in Stockholm in 1956 to receive the Nobel Prize for inventing the transistor.

By the mid-1950’s physicists and engineers began recognizing the transistor’s significance. A small innovative company, Texas Instruments, began producing small, portable transistor radios. A little-known Japanese company named Sony soon surpassed Texas Instruments. By 1961 transistors were the basis of a billion-dollar semiconductor industry. The majority of transistors in that era were used in radar and guided missile systems.

Another more technical source about the history of transistors is here.

Sunday, August 4, 2019

Democratic demagogues about health insurance

I watched part of the Democratic presidential candidates’ debate on July 30-31. There was no shortage of demagoguery about health insurance.

Oft-mentioned was a “public option” as an alternative to Medicare for All. Except for being optional (for those not eligible for Medicare per current rules) rather than forced (Medicare for All), what exactly this meant when any of the candidates used the term was far from clear. It seems that each candidate expects each viewer to take it to mean whatever the viewer wants provided it’s very favorable. In other words, it’s like Barack Obama saying “hope and change” -- an empty warm fuzzy.

The term might refer to several different things. One of those things already exists – insurance purchased on the “marketplace exchanges” created by Obama’s Affordable Care Act. Anybody without health insurance can buy it that way. The coverage is provided by private insurance companies with the federal government having a heavy hand in controlling what’s available. Policies are guaranteed-issue, which translates to the applicants can’t be rejected for pre-existing conditions. (If a person applies for off-exchange insurance, the company can underwrite and possibly deny coverage.)

The most likely meaning is an expansion of Medicare. People not currently eligible for Medicare – mostly people less than 65 years old – could optionally enroll in Medicare. Unsaid is how much the premium would be. It seems the candidate wants the audience to simply believe it would be much cheaper than buying insurance in the private sector, or even free for many. The Medicare Part B premium is now $135.50 per month – more for higher income folks. People who aren’t eligible for free Part A coverage also pay premiums for that. The current amount can be up to $437 per month. A young person in good health could find private health insurance for much less than $135.50 per month.

A New York Times article is titled ‘How a Medicare Buy-In or Public Option Could Threaten Obamacare.’ How would it threaten it? The article hints premiums and reimbursement rates to providers. In other word, the devil is in the details, about which the candidates are silent.

Another kind of demagoguery often heard was the price of prescription drugs. It seems the candidates want the audience to believe the cost of drugs to patients is skyrocketing and drug makers and distributors are making exorbitant profits. Reality says different. This article – from the federal government’s Centers for Medicare & Medicaid Services – is titled ‘Medicare Part D premiums continue to decline in 2019’!

The ultimate demagogue, Bernie Sanders, said: “Right now, we have a dysfunctional health care system—87 million uninsured or under-insured, 500,000 Americans every year going bankrupt because of medical bills, 30,000 people dying while the health care industry makes tens of billions of dollars in profit.”

 The guy gets his “facts” from some fantasy world.

1. There are nowhere near 87 million uninsured. He included the weasel-word “under-insured.” By what standard – they have co-pays or deductibles or no dental insurance?
2. Whence his 30,000 people dying? About 2.8 million people died in the USA in 2017. Over 2 million of those were over age 65, with most of them on Medicare!
3. He probably meant “health insurance industry” rather than “health care industry” Anyway, do the 30,000 people die because the health care/insurance industry makes tens of billions of dollars in profit? If the industry made a much smaller profit, would the number dying be much less than 30,000?
4. How much does the health insurance industry pay in claims? More than $100 billion, but Bernie omits that inconvenient fact.
5. Bernie, ardent Marxist that he is, loves to deride profits. Hey, Bernie, near 100% of your salary and book royalties are profits. Profit = income minus expenses incurred to get that income, and your expenses are miniscule.

Friday, August 2, 2019