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EE42 / 100 – Course Introduction and Fundamental Concepts

Reading Material:Chapter 1

EE42/100 – Vivek Subramanian Slide 1-1

Course Outline / Requirements• Professor

– Vivek Subramanian, EECS– 513 Sutardja Dai Hall (SDH)

• Lectures– Wednesdays and Fridays, 4pm-5:30pm, 10 Evans

• Office Hours– Thursdays, 2pm-3pm– Fridays, 3pm-4pm– Or, you can email me for an appointment if you aren’t able to

make regular office hours• go to http://www.eecs.berkeley.edu/~viveks/schedule.htm• Pick a free time on my schedule• Email me and wait for confirmation


TAs

• tbd


The Textbook• Circuits

– By Ulaby and Maharbiz– NTS Press

• Why?– Good text with lots of real-

world examples– Cheaper than competitors– Maharbiz is now @

Berkeley, and may give you some lectures if scheduling requires / permits

– Coordinates better between EE40/42/100


Course Plan• We will generally follow the content of the text, but with important

additions / subtractions• The course notes are your primary guide, and they are

INTENTIONALLY sparse so you HAVE to attend lecture• EE100

– Homework: 15%– Tests (approx. 1/month): 40%– Final Exam: 30%– Lab: 15%

• EE42– Homework: 15%– Tests (approx. 1/month): 50%– Final Exam: 35%


Policies• Tests

– No makeup exams– If you clear your absence ahead of time, or have a documented

medical excuse, your grade will be averaged from your other tests• Homeworks

– You can miss 1 HW– Else, your lowest score will be dropped

• Cheating– No excuses; I will seek the maximum penalty and fully follow the

department policy (except, I don’t allow repetition of work under *any* circumstance) http://www.eecs.berkeley.edu/Policies/acad.dis.shtml


Peek inside a cell phone


Cell phone architecture


Cell phone by EE courses


EE “Layers”


Some EE history and highlights


Power supplies for all occasions


Piezoelectricity

• Electricity generated by mechanical deformation– Stretching, compressing, etc.– Rochelle salt (potassium sodium tartrate,

KNaC4H4O6) can generate kV when struck!


Making Rochelle Salt

Heat until bubbling stops

Voila! Home-made Rochelle salt

(polycrystalline)


Crystallizing from Solution– Select a nice-looking crystal from the lot and use it as a seed for

recrystallization.– Make a saturated solution of the crystals you did not choose for the seed. – Use a small thread to suspend the seed into the middle of this solution.

– Leave the whole thing alone to evaporate. Growth takes place around the seed, generally at the rate of about a centimeter

per day or two


It’s hammer time!– Once a good-sized crystal is produced, place it on some tissue paper and

let dry completely.– Use a thin layer of Vaseline to place 2 aluminum foil electrodes on

opposite crystal faces. – Connect small neon bulbs to these electrodes.

These bulbs will light up when the crystal is struck. It is possible to light up ~10 bulbs in series, indicating

voltages of about 1000 volts!


Make your own batteries

• To make a battery, take two dissimilar metals and immerse in an electrolyte. – Eg: a penny, a nickel, and a paper towel soaked

in salt water (or vinegar, or ketchup, or lemon juice, or a potato or...).

You’ll get about 0.5V open circuit, with a peak short circuit current of

0.5mA.


Before those pesky cell phones….


Telegraphy


Transatlantic communication


Radio through the agesSpark gap transmission – Marconi, 1985

AM Radio – Fessenden, 1906

Short Wave Radio – Fessenden, 1906

FM Radio – Armstrong, 1931

Digital Radio – XM Corp., 2000


First radio broadcast

Marconi, Hertz, etc., 1880s - 1900

Essentially, a giant spark plug transmitting broadband digital information!


Hertz’s cellphone?

Hertz used a spark-gap as a detector as well. Unfortunately, since detection was visual (i.e., a visible spark had to be generated by the

incoming signal), the power requirements were quite large.

This would not have boded well for those of us with metal dental work


The first live sport broadcast

In 1899, Marconi contracted with the New York Herald and the Evening Telegram to provide up-to-the minute coverage of the

America’s cup Yatch Race

Marconi made quite a few bucks on this deal, and this set up….


The first “Network” ratings wars

Since there was money to be made….

1901 America’s CupMarconi

Lee de Forest

Clearly, the world needed a tuned wireless broadcasting system

American Wireless Telephone &

Telegraph


Semiconductors, diodes, coherers, and other black magic

The birth of the wireless age


The first radio receiver - coherers

Black magic at its best – even today, no one can fully explain how a coherer works! A tube filled with loosely packed metallic powder

Normally has a high resistance (M), but goes to a lower resistance (K) when exposed to an EM signal. It needs to be “whacked” with a hammer to take it back to it’s

high resistance state

Marconi EE42/100 – Vivek Subramanian Slide 1-27

What is AM radio anyway?

Fessenden's Brant Rock station, circa 1906


Demodulation


Early Transmitters

Poulsen transmitter (1914) -Rotating motor creates periodic spark


Early Detectors

The Marconi magnetic detector – uses effect of impinging E field to cancel internal magnetic field. Digital only

Vacuum tube detector –rectifies to allow “envelop detection”. True AM radio.


A history of semiconductors

• 1st description of semiconducting behavior by Carl Ferdinand Braun in 1874 – galena (PbS)– iron pyrites (FeS2 ,commonly known as fools’ gold)– tennantite/tetrahedrite (Cu3AsS3-4/Cu3SbS3-4)– chalcopyrites (CuFeS2/Cu2S•Fe2S3)

• 1st group IV semiconductors 3 decades – Gen. Henry Harrison Chase Dunwoody discovered SiC’s

semiconducting nature in 1907.– At nearly the same time, Greenleaf Whittier Pickard discovered that

silicon was an excellent semiconductor.


Cat’s Whisker Diodes• Pickard studied over 30,000 combinations of minerals and

contacting wires (whimsically known as catwhiskers) – most common: zincite (ZnO) and bornite (Cu5FeS4), – Pickard named it the Perikon detector, for PERfect pIcKard

cONtact.

Pickard was clearly a better scientist than a product marketeer!


Semiconducting PenniesCuO is a passable semiconductor• Obtain a penny dated no earlier than 1983.

– Older pennies are a homogeneous alloy of copper and zinc (in 95/5 ratio), and the zinc poisons the action.

– Newer pennies are almost entirely zinc, on which has been electroplated a 10-15m coating of very pure copper.

• Clean the penny thoroughly – Do not use abrasives (remember, the

copper coating is exceedingly thin).


The point-contact penny diode• Rinse and dry• Bake in a preheated oven (at least 500F) for 15-30 minutes.

– Turn off the oven and let it cool. Verify that the pennies are now covered uni-formly with a nice, dark brownish film.

• For a catwhisker– Use a bent safety pin,

using the lightest touch. – A pencil lead is even

better because it has a little more “give” to it


Crystal Radio

Simplest AM radio – was the basic radio receiver concept through the 1920s


Even better crystal radios…

• Use RF power for amplification as well…


The “Fox-hole” Radio (1940s)

• Rusty razer blade (Fe2O3)• Gillette “Blue Pal” – thin oxide coated

blade


The Audion

The first triode, patented by de Forest, but probably stolen from

Fleming


Armstrong RadiosArmstrong invented amplification

schemes that dramatically improved reception quality, and allowed the use of

small antennae

De Forest watch – Good ol’ Lee hated Armstrong with a vengeance and claimed that Armstrong was a hack. Unfortunately, de Forest couldn’t even explain how his “invention”, the Audion, actually worked, while

Amstrong could.Armstrong committed suicide when he wrongfully lost a lawsuit to de

Forest


Tuned Frequency ReceiversUntil the widespread takeover of the radio waves by FM, creative people designed amazing

sophisticated AM receivers

Problem: The available tuned circuits were far from ideal, so adjacent frequencies were also detected

Solution: Use multiple stages to successively increase selectivity

How do you tune a circuit?


Tuning multiple amplifiers

Multiple rotary capacitors all tied to the same splindle

Problem: Misalignment could degrade selectivity


Superheterodyne RadioProblem with TFR – required high frequency amplifiers

Solution – reduce freqency to workable value and then use TFR – called the superheterodyne receiver

Superheterodyne recievers dominated AM radio for 40 years, finally being replaced by digital AM radios


Transistors


Early transistor-based systems


How does a transistor work?


The Integrated Circuit


Why are IC’s important?


State of the art IC’s


Circuits


Analog Circuits


Digital Circuits


Computers


Units, Multiples, Notation


Charge and Current


Charge & Current• Unit of charge = coulomb


Charge and Current


Counting Charge


Motion of Charge


Time dependence of Current


Example: Charge Transfer

• Given:

Determine: (a) q(t)(b)

Solution:


Example: Charge Transfer (cont.)

(b)


Voltage


Voltage


Reference/Ground• Choose reference point for potential • Assign potential at reference = 0, called ground• Now all potentials are relative to ground terminal


Measuring Voltage & Current

• Voltmeter: measures voltage without drawing current• Ammeter: measures current without dropping voltage


Open Circuit & Short Circuit• Open circuit: no path for current flow (R = )• Short circuit: no voltage drop (R = 0)


PowerRate of expending or absorbing energy

vidtdq

dqdw

dtdwP

Energy conservation

Units: watts

0P

One watt = power rate of one joule of work per second. 1 W = 1 A x 1 V


Circuit Elements: Independent Sources


Circuit Elements: Dependent Sources


I-V for Sources

• Current/voltage fixed for independent sources– What does a non-ideal source

look like?• Dependent sources vary with

reference voltage/current– What are units for slope?


Example: Dependent Source

• Given:

Determine:

Solution:

Source is CCVS


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