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Job interview help! Good analog primer?

Discussion in 'Electronic Design' started by Lewin A.R.W. Edwards, May 12, 2004.

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  1. Hi all,

    I'm going to a second-round job interview next Monday, and I've been
    forewarned by the first-round interviewer that I will be asked
    questions on analog and RF topics (basic op-amp circuits, transistors
    used in switching and amplification apps, superhet receivers and AM
    transmitter).

    I'm not being expected to demonstrate extreme skill (my primary
    function is firmware and digital, analog and particularly RF are not
    my strong point - and I made this clear to them before ever coming in)
    but I would like to have as good a briefing as possible. He
    recommended the ARRL Radio Comms handbook, which is totally
    unavailable near me (libraries, bookstores, etc). I ordered a copy
    from amazon, but I'm worried that it won't arrive in time.

    So, can anyone suggest other references that are either available
    online, or likely to be in Barnes and Noble? I'm looking for
    introductory overview type information rather than detailed
    down-to-the-last-electron info.

    AAMOI: the interview technique he used was, among other things, to
    give me a large mixed-signal schematic and a stuffed board, and leave
    me to look at it for 15 minutes, then I had to describe as far as
    possible the function of the various blocks in the circuit. I did
    tolerably well on that. But the second part of the test was 15 minutes
    with a snippet (~10 pages) of assembly source for a micro I'd never
    used. THAT was fun. Didn't do at all well on that. Oh well. I hope the
    aim was to observe behavior under stress :)

    Any assistance will be karmically rewarded :)))
     
  2. John Larkin

    John Larkin Guest

    Win Hill's book, The Art of Electronics, would be a good cram course.
    It's available everywhere.

    John
     
  3. Joe Legris

    Joe Legris Guest

    How about applying for a job for which you are actually qualified? If
    you cannot answer these questions without cramming even your digital
    "skills" are bogus. I seem to recall your last job at Digi-Frame (?) and
    your heart-rending series of accounts of their financial difficulties
    and your resulting "ethical" dilemmas. Where are your ethics now?
     
  4. CBFalconer

    CBFalconer Guest

    I have my doubts that it will be too helpful. That is full of
    cookbook formula, and very little basic theory, which makes it a
    useful reference. At least it used to be so.

    You might do well snooping around university stores and looking
    for books used in some of the introductory courses. Similarly any
    technical schools in your area.

    Taking your subjects in order, to my mind the critical facets are:

    op-amps: Feedback.

    transistors: leakage currents, breakdown voltages, beta.

    superhet: sum/difference frequency to get constant frequency IF.
    There are systems with tunable IFs also (IF = intermediate
    frequency). Image frequency rejection.

    AM transmitter: Output amplifier classes (A, B, C) and
    modulation. Class C and modulation don't mix very well.

    Sounds like a place that would value all my ancient obsolete
    knowledge.
     
  5. Bob F.

    Bob F. Guest

    What about electromagnetic theory, antennas, transformers, microwaves. Do
    you need to know any of this? Good luck cramming it all in this weekend!

    To further hasten your generation's tendencies to cheat rather that take the
    time to actually LEARN a subject, let me offer you the following
    second-round technical interview tips:

    It sounds to me like they'll be doing something like showing you simple
    operational amplifier circuits and asking you to decide if its an
    integrator, a differentiator, a voltage follower, an inverting amplifier.
    Learn what these op-amp configurations and their gain equations look like.
    For example, the gain equation of an inverting amplifier is A = -RF/RI
    (Just to clue you in here, 'A' is the symbol for Gain, 'RF' symbolizes the
    feedback resistance, 'RI' symbolizes the input resistance).

    If they are testing you on transistors, they'll probably ask you "Is this a
    P-N-P, or an N-P-N?" "Is this a push-pull amplifier" You might actually
    try memorizing the transistor symbols so that you can differentiate a
    bipolar transistor from a FET.

    Can you spot the difference between a low-pass filter and a high-pass
    filter? Didn't think so, why don't you look that one up too!

    Can you spot the difference between a capacitvely-coupled circuit and a
    transformer-coupled circuit? Do you even know what capacitors and
    transformers are?

    During your interview, be don't miss the flux-capacitor, its a common
    component usually attached between Vcc and Gnd.

    Good luck and let us know how you do!
     
  6. Dbowey

    Dbowey Guest

    cbfalconer posted, among other things:

    << AM transmitter: Output amplifier classes (A, B, C) and modulation. Class C
    and modulation don't mix very well. >>

    Actually, class C and modulation mix very well. For high-level (plate)
    modulation, the class C RF amplifier provides the non-linear function required
    for modulation of the RF signal.

    Don
     
  7. Rob Turk

    Rob Turk Guest

    If you want ARRL books, find a Ham Radio Outlet shop (www.hamradio.com) near
    you. They usually have the entire ARRL line of documentation readily
    available. If you're outside the USA, call your local ham radio group and
    ask where to get those books.

    But as the other posters already suggested, I can only wish you luck in
    reading that much info, let alone understand it. Would you be able to tell a
    Colpitts oscillator from a Hartley after reading the basics on transistors
    or opamps? I doubt it. Best is to be fit for the interview and keep an open
    mind. That might work better than being dead-on-arrival from studying all
    weekend...

    Rob
     
  8. Dbowey

    Dbowey Guest

    Joe Legris posted to Lewin:

    << How about applying for a job for which you are actually qualified? If you
    cannot answer these questions without cramming even your digital "skills" are
    bogus. I seem to recall your last job at Digi-Frame (?) and your heart-rending
    series of accounts of their financial difficulties and your resulting "ethical"
    dilemmas. Where are your ethics now? >>

    Well, Joe, where are your ethics?

    Do you really just "seem to recall," or do you in fact recall? One should not
    run off at the mouth about things of which they are not certain.

    I'm certain you are a jerk.
     
  9. maxfoo

    maxfoo Guest

    maybe LTspice?
    http://www.linear.com/software/


    Remove "HeadFromButt", before replying by email.
     
  10. Al Cohen

    Al Cohen Guest

    Ouch. Analog is very non-trivial.

    First, I'd second the recommendation of another poster by suggesting
    Horowitz & Hill's "The Art of Electronics" as a good all-around reference.

    Don Lancaster is an amazing resource, www.tinaja.com.

    If I were looking for a firmware person, the most I could reasonably
    expect them to understand would be op-amp circuits. In general, at
    least in the real world, most analog circuits are built of little blocks
    that usually revolve around an op-amp with some feedback from output to
    input. Common building blocks include:

    - inverting amplifiers
    - non-inverting amplifiers
    - filters (a big topic - lots of variations here)
    - comparators (sort of like op-amps with no feedback)
    - integrators
    - instrumentation amplifiers

    A little on transistors. Transistors are usually brought in to boost
    current-handling capabilities when op-amps can't cut it, although there
    are many other uses for transistors as well.

    There's about a billion other things that one can know about analog
    circuits; but it takes years and years of frying things to learn most of it.

    Good luck!

    Al Cohen
    www.alcohen.com
     
  11. How about applying for a job for which you are actually qualified? If

    Charming. Yes, I also eat small kittens for breakfast, rob the
    elderly, kick puppies, and routinely throw kindergarteners in front of
    buses.

    I would not bother applying, let alone going to a first-round
    interview, for a job that I couldn't do. What on earth would be the
    point? They would know within ten minutes that I didn't have a clue. I
    described my analog knowledge as rudimentary and RF as practically nil
    up-front, before even coming in for an interview. I simply haven't
    needed such knowledge in the jobs I've worked, and my education has
    been project-driven for most of my working life.

    As I understand it, the context of this info is primarily being able
    to understand what the analog peripherals are doing without being too
    much of a load asking questions of the design team. The duties in the
    job description do NOT include RF or analog design.

    It has also been stated to me that if I'm offered the position, it
    will basically be conditional on my going back to school. Implication
    from that being that they understand I'm not a perfect match for every
    bullet point on their list, but they are willing to work with that.
    Also, as you doubtless well know, most job descriptions read "The
    ideal candidate will have 25 years' experience in designing spacecraft
    and nuclear submarines, at least one platinum solo R&B album, a
    distinguished military service record, a personal letter of
    congratulation from the Pope, and will be a former champion sumo
    wrestler and/or ballerina." Few hiring managers succeed in matching
    all bullet points on their wishlist.

    So, kindly don't make such accusatory statements without a solid basis
    of fact. People who matter read public forums like this. I believe I
    have a reasonably consistent and solid sense of ethics, and I KNOW I
    have an excellent comprehension of my own limitations, and I don't
    much care for people who jump to unwarranted conclusions and then
    slander me in public.

    Oh yes - As I recall, I also posted the previous thread to which you
    refer anonymously, so that it could not directly be associated with me
    (e.g. by potential acquirers of my current employer, who would
    perceive significantly diminished value in the company if I were to
    leave it). Some people - and you may have been one of them -
    successfully reverse-engineered my identity from my writing style,
    which is something I could not avoid. The ethical thing for you to do
    in such a case is to respect my desire to keep the original thread
    anonymous.
     
  12. Al Borowski

    Al Borowski Guest

    There's no reason to be condensending. And stereotyping an entire
    generation as 'cheaters' is just arrogant.

    Al
     
  13. (numerous pieces of humor). See my response to Legris, but I'm not as
    irritated at you as I am at him.

    When I say my analog knowledge is rudimentary, I don't mean I can't
    identify a transistor or use one in a simple switching or
    uncomplicated amplifier application, or use a Darlington pair to drive
    a motor, or put in a snubber diode to mitigate inductive kickback. I
    mean, for example, that I can't just glance at an op-amp configuration
    and know immediately what it is; I need to think about it and even
    then I don't always get it right. It's been a long time since I read
    about these things, and it's not information I've often had to think
    about or use, hence my lack of facility with it.

    As for RF, well, I don't do it.

    I'm not interested in acquiring several years' knowledge in a weekend;
    even if I wanted to try it, I am positive that any such attempt would
    be detected instantly by the people I'm talking to. I'm looking for a
    reference that will remind me of where the larger holes are in my
    knowledge, and will stretch some temporary walkways over the smaller
    holes.

    I'm not even sure it is worth my while spending the weekend on this
    rather than doing some of the actual work I have queued up, but I
    figure I should give it extra effort because the job sounds
    interesting. The world will not end if I don't get an offer.

    I think I gave too much contextual information in the question. I
    could simply have said "I was recommended this book as containing XYZ,
    what other book covers similar ground?" My mistake, won't happen
    again.
     
  14. (numerous pieces of humor). See my response to Legris, but I'm not as
    irritated at you as I am at him.

    When I say my analog knowledge is rudimentary, I don't mean I can't
    identify a transistor or use one in a simple switching or
    uncomplicated amplifier application, or use a Darlington pair to drive
    a motor, or put in a snubber diode to mitigate inductive kickback. I
    mean, for example, that I can't just glance at an op-amp configuration
    and know immediately what it is; I need to think about it and even
    then I don't always get it right. It's been a long time since I read
    about these things, and it's not information I've often had to think
    about or use, hence my lack of facility with it.

    As for RF, well, I don't do it.

    I'm not interested in acquiring several years' knowledge in a weekend;
    even if I wanted to try it, I am positive that any such attempt would
    be detected instantly by the people I'm talking to. I'm looking for a
    reference that will remind me of where the larger holes are in my
    knowledge, and will stretch some temporary walkways over the smaller
    holes.

    I'm not even sure it is worth my while spending the weekend on this
    rather than doing some of the actual work I have queued up, but I
    figure I should give it extra effort because the job sounds
    interesting. The world will not end if I don't get an offer.

    I think I gave too much contextual information in the question. I
    could simply have said "I was recommended this book as containing XYZ,
    what other book covers similar ground?" My mistake, won't happen
    again.
     
  15. Tim Auton

    Tim Auton Guest

    Why not the local university library? Over here (the UK) most are
    happy for you to wander in and use the resources if you say hello and
    stick to the rules. You can even borrow books for a moderate fee;
    borrowing from my local university library costs about £25 ($40) per
    year for non-students/staff.


    Tim
     
  16. So they have renamed book in addition to watering it down.

    If you can get a hold of an edition around 1990, the first few
    chapters should give just the right type of information you need. The
    official name in those days was "The ARRL Handbook for Radio
    Amateurs", which might help you locate it in a library.

    Unfortunately about 10 years ago the handbook was reorganised and
    watered down, making it less suitable as general electronics text
    book.

    Paul
     
  17. Mike Switch

    Mike Switch Guest

    I like this book for a quick refresher on topics I need to review:

    The Benchtop Electronics Handbook, Veley, Victor F.C., McGraw-Hill

    Probably available at Amazon, but possibly at your local library also.

    HTH,

    Mike
     
  18. Fred Bloggs

    Fred Bloggs Guest

    EXCELLENT RESPONSE! It is not like he is trying to review or "brush up",
    but the effort is more along the lines of acquiring material for an act.
    He should come clean and tell the interviewer he has no interest in
    analog whatsoever, doesn't know a thing about it, and doesn't want to
    know anything beyond the most essential information required for an
    application- the analog portion of anything he works on is best done by
    someone else.
     
  19. Fred Bloggs

    Fred Bloggs Guest

    Nah- it's called being realistic- most of your riffraff generation
    signed up for an EE major to get a "high paying" job- and aren't worth a
    sh_t- 80% are out of the industry within the first five years of
    graduation. I'd say that 90% of the present undergraduate population
    wouldn't have qualified for *any* education beyond high school by even
    1960 standards...they just don't have the endowment or work ethic to
    succeed in a legitimate curriculum.
     
  20. CFoley1064

    CFoley1064 Guest

    Subject: Job interview help! Good analog primer?
    Hi, Mr. Edwards. If I could add a few suggestions...

    * On follow-up interviews, they're interested in finding out other things
    besides your ability to pass an employment test. If he suggested the ARRL
    Handbook, you *have* to get that, and look it over. Get the most recent
    version (don't be dismayed by the high price -- if you're making this a career
    and you're serious about being an EE, the book is a necessity and will pay for
    itself many times over, whether you get this job or not). One of the goals of
    the second interview may be to see if you can follow instructions.

    * If you didn't ask for Fed Ex, get back to Amazon immediately and order one
    with the fastest possible shipping. You should get it by Saturday morning at
    the latest, which should be enough time to scan through the book, looking at
    the areas they specified. Put on a pot of coffee, and dedicate the weekend to
    it. You'd be amazed how much is in that wonderful book. When the other one
    arrives, you can return it.

    * Everyone who gets an EE has, of necessity, some gaps in their knowledge
    base. That's to be expected. After all, you've only got four years, and
    there's so much else to do in college. Long term, the junior engineer who will
    be the most successful fit is the one who is willing to spend some of his own
    time to get up to speed, and who will accept direction from the mentoring
    senior engineers. It seems to me you've been asked to spend some of your own
    time to get up to speed and accept some direction from a mentor here.

    * While you're at amazon, get The Art of Electronics, too. It's also a great
    investment.

    Sorry about the rather gruff reception you've gotten here. Engineers, even
    good ones, can be like that sometimes. The thing is, nearly all engineers
    respect proven competence, and that will develop with time. Just hold your
    head up, keep working, and do the best you can -- you proved in college that's
    good enough.

    Good luck with the interview (luck being the residue of hard work)
    Chris
     
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