Sound Waves, Phonograph, Stylus, Piezoelectric & Magnetic Cartridges, Thermionic Emission, Vacuum Tube, PN-Junction, Transistor and Amplifier

Posted by PITHOCRATES - May 2nd, 2012

Technology 101

The First Phonographs used a Stylus attached to a Diaphragm to Vibrate the Air and a Horn for Amplification 

Sound is vibration.  Sound waves we hear are vibrations in the air.  A plucked guitar string vibrates.  It transfers that vibration to the soundboard on the guitar body.  The vibration of the soundboard vibrates the air inside the guitar body.  Amplifying it.  And shaping it.  Giving it a rich and resonant sound.  Creating music.  And we can reverse this process.  Taking these vibrations from the air.  And putting them into a piece of wax.  Via a vibrating needle.  Or stylus.  Cutting wavy grooves into wax.  And then we can even reverse this process.  By dragging a stylus through those same wavy groves.  Causing the stylus to vibrate.  And if we transfer those vibrations to the air we can hear those sound waves.  And listen to the music they make.

The first phonographs could reproduce sound.  But they didn’t sound very good.  The first phonographs were purely mechanical.  A stylus vibrated a diaphragm.  The diaphragm vibrated the air.  And a horn attached to that diaphragm was the only amplification.  Sort of like cupping your hands around your mouth when shouting.  Which reinforced and concentrated the sound waves.  Making them louder in the direction you were facing.  Which is how these early phonographs worked.  But the quality of the sound was terrible.  And played at only one volume.  Low.

Electric circuits changed the way we listen to music.  Because we could amplify those low volumes.  By changing the vibrations created from those wavy grooves into an electrical signal.  The first phonographs used a piezoelectric cartridge.  Which the stylus attached to.  The piezoelectric cartridge converted a mechanical pressure (the needle vibrating in the wavy groove) into electricity.  Later phonographs used a magnetic cartridge.  Which did the same thing only using a varying magnetic field.  The vibration of the needle moved a magnet or a coil through a magnetic field.  Thus inducing a current in a coil.  Then all you needed was an amplifier and a loudspeaker to make sweet music.

Small Changes in the Control Grid Voltage of a Vacuum Tube make Larger Changes in the Plate Voltage

The first amplifiers used vacuum tubes.  Things that once filled our televisions and stereo systems.  Back in the old days.  Up until about the Seventies.  A vacuum tube operated on the principle of thermionic emission.  Which basically means if you heat a metal filament it will ‘boil off’ electrons.  The basic vacuum tube used for amplification consisted of a cathode and an anode.  Or filament and plate.  And a control grid in between.  Sealed in, of course, a vacuum.  Creating the triode.  The cathode (filament) and anode (plate) created an electric field when connected to a large power source.  The cathode is negative.  And the anode is positive.  When negatively charged electrons are ‘boiled off’ of the cathode the positive anode attracts them.  The greater the heat the greater the thermionic emission.  And the greater the current flow from cathode to anode.  Unless we change the electric field to inhibit the flow of current.  Which is the purpose of the control grid.

Small changes in the control grid voltage will make changes in the large current flowing from cathode to anode.  That is, the larger current replicates the smaller signal applied to the control grid.  This allows the triode to take the low voltage from a phonograph cartridge and amplify it to a higher voltage with enough power to drive a loudspeaker.  Which is similar to diaphragm and horn on the first phonographs.  Only the amplified electric signal moves a lot more air.  And better materials and construction create a better quality sound.  Amplifiers with vacuum tubes make beautiful music.  High-end audio equipment still uses them to this day.  Including almost all electric guitar amps.  So if they have the highest quality why don’t we use them elsewhere?  Because of thermionic emission.  And the heat required to ‘boil off’ those electrons.

Vacuum tubes worked well when plugged into line power.  Such as a radio in a house.  But they don’t work well on batteries.  Because it takes a lot of electric power to heat those filaments.  And you need pretty big batteries to get that kind of electric power.  Like a car battery.  But even a car battery didn’t let you listen to music for long when parked with the engine off.  Because those tubes drained that battery pretty fast.  So there were limitations in using vacuum tubes.  They draw a lot of power.  Produce a lot of heat.  And tend to be pieces of furniture in your house because of their physical size.

Small Changes in the Base Current of a Transistor is Replicated in the Larger Collector-Emitter Current

The transistor changed that.  Making music more portable.  Thanks to semiconductors.  Material with special electric properties.  Based on the amount of electrons in the atoms making up this material.  Atoms with extra electrons make material with a negative charge (N-material).  Atoms missing some electrons make material with a positive charge (P-material).  When you put these materials together the N and the P attract each other.  Electrons cross the junction and fill in the holes that were missing electrons.  And the ‘holes’ cross the junction and fill in the spaces where there were excess electrons.  (When an electron moved, say, from right to left it made a hole and filled a hole.  It made a hole where it once was.  And it filled a hole where it now is.  So it looks like the hole moved from left to right when the electron moved from right to left.)  Neutralizing the N-material and the P-material.  But creating a charged region around the junction.  And it’s this electron flow and hole flow that make these PN junctions work.  When you add a third material you get a transistor.  Made up of three parts (NPN or PNP).  Emitter, base, and collector.

To get the electrons and holes flowing you start applying voltages across the junctions.  A large current will flow from the collector to the emitter.  Similar to the current flow in a tube from cathode to anode.  And a small base current will change that current flow.  Just like the control grid in a vacuum tube.  Small changes in the base current will make similar changes in the larger collector-emitter current.  Just like in a vacuum tube, the larger current replicates the smaller signal applied to the ‘control’.  Or base.  This allows the transistor to take the low-level signal from a phonograph cartridge and amplify it to a higher level.  Just like a vacuum tube.  Only with a fraction of the electric power.  Because there are no filaments to heat. 

Low power consumption and the small physical size allowed much smaller amplifiers.  And amplifiers that everyday batteries could power.  Creating new ways to listen to music.  From the pocket-size transistor radio.  To the bigger stereo boombox.  To the iPod.  Where the basic principle of how we listen to music hasn’t changed.  Just how we vibrate the air that makes that music has.


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Boolean Algebra, Logic Gates, Flip-Flop, Bit, Byte, Transistor, Integrated Circuit, Microprocessor and Computer Programming

Posted by PITHOCRATES - February 1st, 2012

Technology 101

A Binary System is one where a Bit of Information can only have One of Two States 

Parents can be very logical when it comes to their children.  Children always want dessert.  But they don’t always clean their rooms or do their homework.  So some parents make dessert conditional.  For the children to have their dessert they must clean their rooms AND do their homework.  Both things are required to get dessert.  Or you could say this in another way.  If the children either don’t clean their rooms OR don’t do their homework they will forfeit their dessert.  Stated in this way they only need to do one of two things (not clean their room OR not do their homework) to forfeit their dessert. 

This was an introduction to logic.  George Boole created a mathematical way to express this logic. We call it Boolean algebra.  But relax.  There will be no algebraic equations here.

In the above example things had only one of two states.  Room cleaned.  Room not cleaned.   Homework done.  Homework not done.  This is a binary system.  Where a bit of information can only have one of two states.  We gave these states names.  We could have used anything.  But in our digital age we chose to represent these two states with either a ‘1’ or a ‘0’.  One piece of information is either a ‘1’.  And if it’s not a ‘1’ then it has to be a ‘0’.  In the above example a clean room and complete homework would both be 1s.  And a dirty room and incomplete homework would be 0s.  Where ‘1’ means a condition is ‘true’.  And a ‘0’ means the condition is ‘false’.

Miniaturization allowed us to place more Transistors onto an Integrated Circuit

Logic gates are electrical/electronic devices that process these bits of information to make a decision.  The above was an example of two logic gates.  Can you guess what we call them?  One was an AND gate.  The other was an OR gate.  Because one needed both conditions (the first AND the second) to be true to trigger a true output.  Children get dessert.  The other needed only one condition (the first OR the second) to be true to trigger a true output.  Children forfeit dessert. 

We made early gates with electromechanical relays and vacuum tubes.  Claude Shannon used Boolean algebra to optimize telephone routing switches made of relays.  But these were big and required big spaces, needed lots of wiring, consumed a lot of power and generated a lot of heat.  Especially as we combined more and more of these logic gates together to be able to make more complex decisions.  Think of what happens when you press a button to call an elevator (an input).  Doors close (an action).  When doors are closed (an input) car moves (an action).  Car slows down when near floor.  Car stops on floor.  When car stops doors open.  Etc.  If you were ever in an elevator control room you could hear a symphony of clicks and clacks from the relays as they processed new inputs and issued action commands to safely move people up and down a building.  Some Boolean number crunching, though, could often eliminate a lot of redundant gates while still making the same decisions based on the same input conditions. 

The physical size constraints of putting more and more relays or vacuum tubes together limited these decision-making machines, though.  But new technology solved that problem.  By exchanging relays and vacuum tubes for transistors.  Made from small amounts of semiconductor material.  Such as silicon.  As in Silicon Valley.  These transistors are very small and consume far less power.  Which allowed us to build larger and more complex logic arrays.  Built with latching flip-flops.  Such as the J-K flip-flop.  Logic gates wired together to store a single bit of information.  A ‘1’ or a ‘0’.  Eight of these devices in a row can hold 8 bits of information.  Or a byte.  When a clock was added to these flip-flops they would check the inputs and change their outputs (if necessary) with each pulse of the clock.  Miniaturization allowed us to place more and more of these transistors onto an integrated circuit.  A computer chip.  Which could hold a lot of bytes of information. 

To Program Computers we used Assembly Language and High-Level Programming Languages like FORTRAN

The marriage of latching flip-flops and a clock gave birth to the microprocessor.  A sequential digital logic device.  Where the microprocessor checks inputs in sequence and based on the instructions stored in the computer’s memory (those registers built from flip-flops encoded with bytes of binary instructions) executes output actions.  Like the elevator.  The microprocessor notes the inputs.  It then looks in its memory to see what those inputs mean.  And then executes the instructions for that set of inputs.  The bigger the registers and the faster the clock speed the faster this sequence.

Putting information into these registers can be tedious.  Especially if you’re programming in machine language.  Entering a ‘1’ or a ‘0’ for each bit in a byte.  To help humans program these machines we developed assembly language.  Where we wrote lines of program using words we could better understand.  Then used an assembler to covert that programming into the machine language the machine could understand.  Because the machine only looks at bytes of data full of 1s and 0s and compares it to a stored program for instructions to generate an output.  To improve on this we developed high-level programming languages.  Such as FORTRAN.  FORTRAN, short for formula translation, made more sense to humans and was therefore more powerful for people.  A compiler would then translate the human gibberish into the machine language the computer could understand.

Computing has come a long way from those electromechanical relays and vacuum tubes.  Where once you had to be an engineer or a computer scientist to program and operate a computer.  Through the high-tech revolution of the Eighties and Silicon Valley.  Where chip making changed our world and created an economic boom the likes few have ever seen.  To today where anyone can use a laptop computer or a smartphone to surf the Internet.  And they don’t have to understand any of the technology that makes it work.  Which is why people curse when their device doesn’t do what they want it to do.  It doesn’t help.  But it’s all they can do.  Curse.  Unlike an engineer or computer scientist.  Who don’t curse.  Much.


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FUNDAMENTAL TRUTH #11: “Before you condemn capitalism, imagine a world without professional sports, movies, cell phones and tampons.” -Old Pithy

Posted by PITHOCRATES - April 27th, 2010

PEOPLE HAVE SOME strong opinions about capitalism.  Both good and bad.  So what is it?  What is capitalism?

Merriman Webster OnLine defines it as:

An economic system characterized by private or corporate ownership of capital goods, by investments that are determined by private decision, and by prices, production, and the distribution of goods that are determined mainly by competition in a free market.

To explain this let’s start by explaining what it replaced.  In fact, let’s go further back.  A few hundred years when life truly sucked by our standards.  During the Middle Ages, people barely lived.  People worked very hard and had little time off.  When they did they usually spent it sleeping, being sick, dying or being dead.  You grew or killed what you ate.  You built your own house.  You made your own clothes.  You died probably no further than a short walk from where you were born.  And you worked your whole life somewhere in between.

Think of peasant or serf.  That’s what most were.  Tied to the land.  You had no choices.  If you were born on the land you worked the land.  Until you died.  The land owned you and someone owned the land.  You worked the land at the grace of the owner.  You helped produce his food and, in return, he let you have a small parcel of land to grow your food.  There was a bond of loyalty between landlord and tenant.  Land and protection in exchange for backbreaking, never-ending labor.  Doesn’t sound good until you consider the alternative.  Death by famine.  Or death by murder at the hands of roving bands of outlaws.

Improvements in farming led to more food production.  Eventually, there were food surpluses.  This meant not everyone had to farm.  Some could do other things.  And did.  They became specialists.  Artisans.  Craftsmen.  Cities grew in response to commerce.  People went to market to trade for things they wanted.  Then they started using money, which made getting the things they wanted easier (it’s easier to go to the market with a coin purse than with a sack of grain or a side of beef).  Life got better.  People enjoyed some of it.

THUS BEGAN THE rise of a middle class.  Those city folk making things or doing something.  They were good at what they did and people gladly paid for what they did.  These specialists then improved what they did and thought of new things to do.  They created things to make their work easier.  These individual specialists grew into manufacturing shops.  The cost of production only limited their output.  And banking solved that problem.

Alexander Hamilton, one of America’s Founding Fathers, was a capitalist.  And he thought big.  Money is nice but what can it get you?  A few things for the home?  Something for the wife?  Maybe some new farm tools.  Good stuff, yes, but nothing big.  Lots of little sums of money all over the place can buy lots of little things.  But when you pool lots of little sums of money you get one big-ass pile of it.  That money is now capital.  And you can do big things with it.

And that’s what banking has given us.  People with ideas, entrepreneurs, could now borrow money to bring their ideas to market.  And this is, in a nutshell, capitalism.  The free flow of ideas and capital to make life better.  Making life better wasn’t necessarily the objective; it’s just the natural consequence of people mutually partaking in a free market.

BUT WHAT ABOUT the Soviet Union?  Didn’t they do big things, too?  They built jetliners.  They had a space program.  They had factories.  They did these and other things without capitalism.  They did these things for the good of the people, not for profits.  Isn’t that better?

Talk to someone who wiped their ass with Soviet-era toilet paper.  Let me save you the trouble.  It didn’t feel good.  Unless you enjoy the feel of sandpaper back there.  And to add insult to injury, you had to wait in line to get that toilet paper.  If it was available.

When you think of the Soviet economy you have to think of stores with empty shelves and warehouses full of stuff no one wants.  This is what a command economy does for you.  Some bureaucrat, not the consumer, determines what to sell.  And one person simply cannot figure out what a hundred million plus want.  To get an idea of how difficult this is, pick a movie that 4 of your friends would love to see.  Pick a couple of guys and a couple of girls.  For diversity.  And remove the possibility of sex completely from the equation.  Now pick.  Not so easy, is it?  Now try to pick a movie a hundred million people would love to see.  Can’t do it, can you?  No one can.  Because people are diverse.  One size doesn’t fit all.

Soviet president Mikhail Gorbachev asked Margaret Thatcher how she made sure her people had enough food to eat.  The Soviets were having difficulty feeding theirs.  In fact, they were importing grain from their archenemy.  The United States.  The answer to Gorbachev’s answer was that Thatcher did nothing to feed her people.  The free market fed her people.  Capitalism.

As far as those other big things the Soviets did, they acquired a lot of the knowledge to do those things through an elaborate network of espionage.  They stole technology and copied it.  And they were the first into space because their captured Nazi rocket scientists did it before our captured Nazi rocket scientists did.  (The seed of the space industry was the Nazi V-2 rocket that reigned terror on London and other cities during World War II).

(Lest you think that I’m ripping on the Soviet/Russian people, I’m not.  Just their economic system during the Soviet era.  Their people have suffered.  And persevered.  It was them after all who first threw back Napoleon in Europe.  And it was them who first threw back the Nazis in Europe.  They gave us Pyotr Ilyich Tchaikovsky, Sergei Rachmaninoff, Leo Tolstoy, Fyodor Dostoyevsky, Mikhail Dolivo-Dobrovolsky and, of course, Maria Sharapova to name just a few of the greats.  Good people.  Just sometimes bad government.  As in most nations.  Even in the U.S.)

SO WHAT IS the basic difference between capitalism and a command economy like that of the former Soviet Union?  Probably the freedom to take and accept risk.  Bankers take a risk in loaning money.  They analyze the risk.  If the return on the loan is greater than the risk, they’ll make the loan.  It’s their call.  And they’re pretty good.  Their successes are far greater than their failures.

Some loans are riskier than others.  There’s a greater chance of failure.  But it could also be the next, say, Microsoft.  Or Apple.  If so, even though there’s great risk, the potential of reward is so great that people will want to loan money.  They’ll buy junk bonds (high risk/high yield) or an initial public offering of stock.  They’ll risk their money for a greater return on their investment.  If it pays off.  And they don’t always do.  But good ideas with potential typically find financing.  And investors typically make more money than they lose.  It’s a pretty good system.  Capitalism.

WHEN YOU HAVE risk takers who choose to participate in the free flow of ideas and capital, great things happen.  Modern AC electrical power that we take for granted is invented (thank you Nikola Tesla for the genius and George Westinghouse for taking the risk).  You develop modern commercial jet aviation (thank you Boeing for the 707, 727, 737, 747, well, you get the picture).  You transform the world when you add impurities to semiconducting material and sandwich them together (thank you John Bardeen, Walter H. Brattain and William B. Shockley for the transistor).

These great things, along with others, give us professional sports (stadiums, transportation to and from the stadium, jetliners to take teams to other stadiums, oil exploration and refining for jet and car fuel, etc.).  They give us movies (financing, cameras and production equipment, special effects, theaters, popcorn, DVDs for home viewing, etc.).  They give us cell phones (cellular towers, switching networks, compact and long lasting batteries, interactive handheld devices, voicemail, email, texting, etc.).  And they liberated women to do whatever they want wherever they want by making feminine hygiene protection portable and plentiful (mass production, rail and truck transport, retail and vending outlets, etc.) and by providing convenient privacy (public toilet facilities with vending machines and disposal bins). 

Imagine any of these things provided by the same people who renew our driver’s license.  Do you think any of it would be as good?  Or do you think it would be more like Soviet-era life?  There’s so much we take for granted in capitalism because we can.  It’s a system that works on basic human nature.  It doesn’t require sacrifice.  It doesn’t depend on consensus.  It just needs the free flow of ideas and capital.  And great things follow.


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