Letters from Pinto
18 August 2004
Dear All,
probably I didn't make myself clear.
The grades are on the EE40 class website, don't look for them on
bearfacts.
Here is the link:
http://wwwinst.eecs.berkeley.edu/~ee40/Summer04/Grades.htm
Again, be honest we yourself first of all, with other students secondly
and we me thirdly.
CIAO
A.
17 August 2004
Dear All,
the grades have been posted on line. You'll find a link on the webpage.
It is mandatory for me to enter the final grades tomorrow before 4 PM.
CIAO
A.
17 August 2004
Sorry,
there are errors on the final grades
A.
17 August 2004
Sorry,
It is so late that I might have done some errors in assigning grades.
If you have concerns of this kind please let me know (but be
considerate,
don't try to ask for a better grades just to give it a try).
Few words before saying good night:
For some of you I was really sorry because I think you could have
gotten a
better grade. For some of you, instead, I know that you probably don't
really deserve what you got.
But again, I do not understand why those numbers have to be given and
this
is the root of the problem.
Good night
A.
16 August 2004
A lot of students cannot make it tomorrow, so let's reschedule it for
Wednesday August 18th form 12PM to 1PM in 277 Cory Hall.
I know that some of you still cannot make it and I'll let them know the
grade by email.
See you then
A.
16 August 2004
Sorry I forgot time and place
WHEN: Tomorrow, 08/17/2004 5PM
WHERE: 277 Cory Hall, the usual place
WHY: Discussion of final exam.
CIAO
A.
16 August 2004
Dear All,
Let's meet tomorrow, Tuesday August 17th to discuss the final together.
Thanks
A.
12 August 2004
My Dear Students,
If I'm allowed to say a word then: "Thanks".
This is taken from a song: "Zion" by Lauren Hill

[...]
But then an angel came one day
Told me to kneel down and prey
For unto me a man child would be born
Woe this crazy circumstance
I knew his life deserved a chance
But everybody told me to be smart
Look at your career they said
"Lauren baby use your head"
But instead i chose to use my heart
[...]

Exactly. One day, I decided to take you, a group of children and not
only,
and let you enter a new world. This has been my mission.
It is not about electronics, It is not about money, It is not about
glory
and It is not even about resume.
What is "It" then?
There are very profound questions to which we don't know how to answer:
Where do we come from?
Why are we here? Or, why were we born?
Where are we going?
Compared to this questions, what is a common source amplifier becomes
ridiculous. It is not only if we put it in a broader context, the
context
of global knowledge.
Born again in a different world and
instruct you how to live in it; this should be all teachers' goal. I
believe that in the world of knowledge "Everybody's life deserve a
chance"
regardless of race, money, and even IQ.
The songs then go ahead and says:
"Now the joy of my world is in Zion" (Zion is her son).
Yes, today the joy of my world is in the wonderful class to which I say
goodbye.
Be free from stereotypes.
Best
Alessandro
11 August 2004
I have posted lec. 14,16,19.
Lec. 14 and 16 are on mosfet, lec. 19 is on logic minimization.
Goodnight
A.
10 August 2004
Answers to some questions tha tI have received:
____________________________________________________________________
I'm not quite sure what you mean by the output range being V_DSmax 
V_Dsmin. I found the output to equal V_GD (although I can write the
output in terms of V_DS if I need to.) Then I found the output range to
be
V_GDmax  V_GDmin = V_DS. Am I doing this correctly? I also got V_DS as
the maximum input range.
A: The input rage is limited by the small signal approximation because
I'm
asking "what is the input range in order for the small signal analysis
to
hold". So you have to consider this. For the output range, you have to
keep the transistor in saturation!!!!
_________________________________________________________________
I have a small problem . I am taking this other class this summer, and
the
exam for that class is bering held during the class hours
that is from 1011:30 am on thursday itself, and you have put the exam
from 111:30 pm....so i cannot make it, would it be possible for you to
shift the exam by 1 hour instead of starting at 11 could you start at
12
pm, so that i can make it to the exam, as my ECON exam is in Dwinelle
and
its quite a walk from Dwinelle to Cory.
A: The final is going to be on Th. from 12 to 2PM
____________________________________________________________________
It seems that to put Vgs > Vt, VI needs to be negative (and Vi <
VI).
Is this what you're intending? Or am I completely missing something?
A: I think this is correct. Anyway, I received a lot of questions of
this
type. Basically you know what you should do but you are afraid to make
mistakes. Then, it is true that this is the age of man (or the age of
reason) as opposed to the age of Heroes (or the age of immagination)
(thi is taken from Giovan Battista Vico).
_______________________________________________________________________
For A.2 and C.1, the small signal expressions, we should assume that
r_d
is not 0, right? The C.1 gain expression is pretty complicated when
r_d1
and r_d2 are nonzero.
A: Designing a PDA that can make phone calls, play DVDs, surf the
internet
while having his battery last in 20days is complicated. The expressions
could be long but still lagebraic...
_______________________________________________________________________
Using DeMorgan laws (x + y)' = x'y' ==> x + y = (x'y') in computing
S3,
S3 should be equal to (b'(a'c')'(ac)')' instead of b'(a'c')'(ac)',
because
S3 = (b'(a'c')')' + ac = (b'(a'c')'(ac)')'.
Thus, we don't need to have one more nand gate added to the output in
order to get S3, because S3 can be obtained by using 4 inverters and 3
nand gates as shown in figure 2.
A: Right
________________________________________________________________
In A, ( as you have corrected in class) your equation of I sat is I = k
(Vgs  Vt) ^2; did you mean there to be a factor of in the equation? I
mean is it supposed to be I = k/2 (vgsvt)^2?
A: Yes
_____________________________________________________________________
In B2, did you mean for the capacitor to be discharged when t=0? If you
let the capacitor to be charged, then isn't the circuit going to start
in
sat mode and then stabilize in sat mode?
A: For t<0 the transistor is in cutoff. So the capacitor can charge at
VDD
because basically the transitor is an open circuit.
____________________________________________________________________
Professor Pinto, can you fix the deadline for the hw at some time, so
that you can post the solution, and we can understand the problems
fully
for the
final.
A: If most people agree, the deadline could be fixed on Wednesday by
5PM.
____________________________________________________________
9 August 2004
My dear Students,
I have posted lab 13, as usual no prelab is required during exam week.
I have to apologize for not having all the lectures posted but I have
three deadlines in one month and I have to spend also some time for
research. I'll do my best.
CIAO
A.
6 August 2004
Dear Students,
This email is long but please read it till the end because there are a
lot of important things.
I have posted solution to HW3. Please read it! Especially the last two
problems because most of you have done them by intuition without
following a method.
I have posted lecture 18, you may want to take a look at it before
tomorrow's class.
There are some people that didn't finish the lab where you were
supposed
to put everithing together. If you want to debug and finish your
experiment then you can go to lab whenever it is open even it is not
your
session.
The final exam is going to be on 8/12 and not 8/13 because some
students
have problems in coming the 13th. I suggest to meet at 11AM, work on
the final until 1.30PM. Then I will go for lunch at Jupiter and if you
want we can go together.
Goodnight
CIAO
A.P.
03 August 2004
has been posted.
This hw might seem complicated but it's not.
Do the practice problems from the book first and then start with the
HW.
CIAO
A.
31 July 2004
Lab 11 and 12 have been posted online.
Please take a look at them.
Have a nice weekend
A.
27 July 2004
Dear students,
I have posted solutions to HW2 and lecture 10 (which you don't really
care
about now).
I have to correct myself. In an excess of formality I gave you a
formula
for computing the modulus of a ration of two complex numbers.
Even if the formula is correct, Renaldi was right and you can just
compute
the ratio of the two abs.
so if z1 and z2 are complex number then
z1/z2 = z1/z2
So now, citing one on my favorite scientists
"Do not worry about your problems with mathematics, I assure you mine
are
far greater" (I'm pretty sure that you knoe who the guy is).
Good night
A.
27 July 2004
Since I really care about your stress level (you might want ot consider
that stress causes memory loss) and since some of you asked, HW3 due
date
is posteponed to Friday 5PM sharp.
This time I ask you to turn in the homework on time, late homework will
not be graded.
CIAO
A.
26 July 2004
Is now online.
If you have time, take a look at it before tomorrow morning.
There is no prelab to turn in.
As usual, we could have a review session tomorrow night.
Unfortunately the whole day if pretty busy.
I could do it from 8PM till 9PM.
I'll be there at 8PM if somebody shows up...
CIAO
A.
26 July 2004
Dear All,
Lab 9 is online. Since you have a midterm on Wednesday I'm not
requiring
you to do any prelab.
The report is required as usual.
CIAO
A.
20 July 2004
Dear All,
I received the following feedback:

I think it is VERY IMPORTANT that you do the basic stuff we need to
learn in EE40, provide more explanation and easy examples BEFORE you
talk you about extra stuffs (that are not in previous years)

Thank you very much for sending it!
There is an on line poll to understand whether it is a common feeling.
Please vote, it is very important for me to understand how should I
proceed with lectures. Also if you want to send me a more complete
answer, please feel free to drop me a line in the feedback form.
Thanks
Alessandro
A NOTE FROM THE INSTRUCTOR

There are no problems for me in adjusting my style to your needs.
Actually, it would be much easier for me to reuse previous years slides
(or material in general) and to follow the book. Preparing the kind of
lectures that I'm giving is very time consuming for me because I have
to
simplify them as much as possible.
There are so many important details that I'm omitting from lectures
that
makes it very difficult to explain you things. Still, I think that you
have now a pretty broad knowledge that allows you to design complex
systems (but maybe you have not yet realized it). For instance, I think
you can easily sketch the block diagram of a television: form power
supply to the CRT driver circuit, to sound elaboration.
Sorry for being to tough with you.
CIAO
A.
18 July 2004
I received few questions concering HW2.
I'm answering to the mailing list because the questions could be
usefull for
everybody.

1. Should we assume that the v in question A can be a sinusoidal
voltage
source (similar to what the textbook does on p. 157), or is it a DC
source?
I'm asking this because if v is a sinusoidal voltage source, it can
affect
the values of A and B in question A.3.II.
A)
Yes, we assume that it is a sinusoid and we do a steady state
sinusoidal
analysis.
V will affect A and B only by its angular frequency. A and B will not
depend
on time because the relation that you will find (which invole sin and
cos)
must be valid at any time so the time dependency will be lost (as I
have
shown in class).

Concerning homework problem C part 2. Knowing that the circuit actually
models a circuit with a capacitor with the initial voltage Vcc*R2/(R1 +
R2),
resistor R3, and a voltage generator initially set at Vcc, I was
trying to
find the time when the capacitor will be discharged and recharged until
the
voltage across it is equal to the current Vy, Vcc*R2/(R1 + R2), after
when
the source Vcc will change polarity to Vcc. My circuit looks like
this:
ground  capacitor  R3  voltage source Vcc  ground.
Using Kirchoff Voltage Law, I got Vcapacitor + Vcc = IR3. Also
utilizing the
equality I = C dv/dt, I changed the function into a differential
equation
and attempted to solve for Vcapacitor with respect to time.
Unfortunately,
the answer came out to be Vcap = e^(t/R3). Since function of e would
never
be negative, the voltage across the capacitor, consequently Vx, will
never
reach
Vcc*R2/(R1 + R2). Not able to find the time in which Vx reaches Vy, I
cannot calculate the period of one cycle, and eventually the frequency,
correctly.
A)
I think the problem is the solution of the differential equation. The
solution should be something like
Vc=Vcc*R2/(R1+R2) e ^(t/(R3*C))  (1e^(t/(R3*C))*Vcc
This equation can give a Vc as low as Vcc.

I'm not sure how to analyze the circuit given in question C) of this
week's
assignment. Since the input voltages are not initially the same, I'm
assuming we need to do some sort of transient analysis, but I'm not
sure
what model we should use for the opamp. Do we just use the standard
model
with the large input resistor and highgain dependent source, defining
parameters as needed? Or am I totally missing the correct method
altogether? Also, I'm not sure why the output will oscillate if there
is
only one reactive element in the circuit, wouldn't this be a
firstorder
circuit, implying that the output should decay exponentially?
A)
Yes this is a good approach. Use a voltage controlled voltage source
with
and infinite gain and an input conductance equal to 0.
Remember that this circutis is not linear so you cannot apply the
resoning
of the second order circtuit. If you have a linear system that in order
to
oscillate it must be a second order circuit (or mode that second order,
also
there is a condition in order to have ascillation which is that the
second
order equation has two imaginary conjugate roots).

In HW#2 A.4), I think you assumed that the gain of 2nd order circuit is
1.
So you gave us the problem A.4) " I) Solve the equation : sqrt(A^2+B^2)
=
1/sqrt(2) "
But I think the gain of this 2nd order circuit is not 1.
(It depends on values of R1, R2, C1, C2).
And even though the gain is 1, the equation, sqrt(A^2+B^2) = 1/sqrt(2),
is
too complex to solve by hand.
A)
The gain depends on the frequency of your circuit. There are two
frequencies
for which the gain is 1/sqrt(2). You have to find them.
Hope this helps.
Ps.: only two students asked a review for the lab so I think I'm not
going
to do it also because I have to leave at 5.45PM.
CIAO
A.
16 July 2004
My Dear Students,
Lab7 is online.
The prelab is a little bit long and I know that this lab is not easy.
Look at it without fears, you are the master and the circuit is your
puppet
don't ever feel that it is the other way around (is like with dogs, if
you
are afraid of them they will byte you).
If you have problems understanding the circuit, it is no your fault by
is
your instructor fault.
So if there are many requests I could spend 1 hour on Sunday (from 5PM
to
6PM) with you to explain the circuit.
Have fun!
CIAO
A.
14 July 2004
Dear All,
I have added:
a link to software for mac os
Other classes around US under links>education
References to books you might want to borrow/buy under
Pubblications>References
Please, don't borrow the books from the library forever. Borrow them,
study
the part that you need in 30 minutes (maybe *copy* the pages in your
mind)
and return it.
Have fun
CIAO
A.
13 July 2004
Dear All,
Sorry for the late notice.
Lab 6 is on line. Since it is late, the prelab is very easy.
The report though, has two questions that you are supposed to answer
to.
The first is a yes or no question, the second will require you to
reason a
little bit.
Have fun
A.
PS.: you would probably like to look at the notes from today's class.
I'm
going to post them in 10 minutes.
13 July 2004
Somebody asked me the spice netlist but I don't remember who.
I'm sending what comes out form 5spice.
Hope this helps.
CIAO
A.
12 July 2004
Dear All,
HW2 is online.
I know that this class is very intensive, I also know that I'm pushing
math
too much (maybe) while you are more interested in seeing practical
circuits,
but please spend a little time in trying to understand the homework.
Don't
do the homework just because it is a duty, try to give your own
interpretation to the problem and to understand the hypothesis and
their
implication (i.e. the results).
Tomorrow, I don't know if I can start with semiconductors. I think we
need
to do the following first:
1)Fix few things: thevenin and norton equivalence and a general method
to
analyze circuits with opamps
2)Find a way of analyzing RLC circuits.
Remember one thing. We know how to solve circuits (nodevoltage and
meshcurrent). We always try to reduce whatever new problem to standard
analysis methods.
Things you'll see tomorrow are all aimed to that.
Goodnight (even if night is almost over)
A.
10 July 2004
Lab 5
Is on line.
There is a prelab this time.
Goodnight
Alessandro
9 July 2004
Dear All,
I posted solutions to most of the review problems (which I posted this
morning).
I hope this can help.
But "There is a flip side to that coin" (Robert de Niro, Heat, 1995), I
could not prepare the lab. I'm going to do it now.
CIAO
A.
8 July 2004
Dear All,
Remember the class tomorrow (Th) from 5 to 7PM in 277 Cory Hall. After
class
I can review few things and solve problems if you want.
LABS

The second step you have to do is to build a tone controller. In order
to do
that you need to be able to measure bandwidth an other things.
Friday will be dedicated to the use of scope and function generator.
Since
Friday is also midterm day, I will not require any prelab but please
STUDY
for the midterm.
HOMEWORK

Even if the homework is ready I will not post it until tomorrow because
I
don't want to look at it before the midterm. Please, FOCUS on the
midterm
only.
I will post few problems tomorrow morning before 9AM. Please work on
them so
that we can go over them in the review session.
CIAO
A.
3 July 2004
Dear All,
Lab3 is on line. Go to labs>lab3.
There are few questions that you have to answer and turn in at the
beginning
of the lab.
CIAO
A.
28 June 2004
Dear All,
Tomorrow's lab is going to be on Spice, a program for circuit simulation.
Please, take a look to the manual (which is posted under "Labs" on the
class website). If you want to can intall one of the millions of versions of
spice (I have put a link on the labs page).
Besides the elegant thory that I have shown you in class, I have to say
that spice uses the MNA (modified voltage analysis) to solve circuits which
is the nodevoltage analysis where you add as many extra equations as
voltage sources (in order to avoid a postprocessing phase to retrive the
original topology).
Homework 1 is posted online. Use the method that you prefer: MNA,
transformation, supernode, supermesh etc. but you have to use both
nodevoltage and meshcurrent. If you really want to undestand I
suggest you
to try evething that bounce in you mind and verify that the result is
always
the same.
There is a link on the website for anonymous feedback. It is very
important
to me, just click on the link and drop me a line.
Thanks
CIAO
A.
