electronics knowlege at BSEE level

This is the place for any magazine-related discussions that don't fit in any of the column discussion boards below.
Post Reply
rocket scientist
Posts: 25
Joined: Mon Jan 03, 2005 1:01 am
Location: san diego
Contact:

electronics knowlege at BSEE level

Post by rocket scientist » Sun Jan 30, 2005 12:05 am

I have recently been interviewing candidates for an entry level E.E. position at my company. I ask simple electronics questions to evaluate candidates. What I find is that what I think are simple questions stump almost all of them. These are students with four years of college training in EE, so I am wondering if I am getting a bunch of dim bulbs, or if my expectations are just too high for this level with no experience. My two basic questions are:<p>1)analog electronics: design a simple passive lowpass (or highpass) filter<p>2)digital electronics: design a half-adder using AND and OR gates. <p>Any educators or recent graduates out there have feedback on this? Remember, this has to be answered 'on-your-feet' at a job interview.

terri
Posts: 404
Joined: Sun Nov 07, 2004 1:01 am
Location: colorado
Contact:

Re: electronics knowlege at BSEE level

Post by terri » Sun Jan 30, 2005 1:20 am

Probably just a question of real-life practice. <p>I could answer the filter thing if I were caught flatfooted like that because I did that not too long ago. But the half adder, I'd have to go back in the books and at least glance at the page before I said "Oh, OK, sure!" I guess that would make me a dim bulb.<p>I think maybe you're expecting a little too much by catching them flatfooted in a high-pressure situation. Maybe giving them a circuit and asking them what it does might be more appropriate. At least then it will give them a visual pattern to get a handle on it, as opposed to just an abstract verbal "pop-quiz." This would probably give you a better idea of their thinking processes, as opposed to whether they just happened to have read the particular textbook sections on those particular devices in the last year or so.<p>One of the parameters of an adequate test question is that some proportion of the "testees" can answer it. If a question can not be answered by anyone in your selected test group (i.e., BSEEs), then the question has no value as a predictor of future performance. And "future performance" is what you're really trying to evaluate. <p>And I would suspect that if one of them could answer it, all you would have is an employee who happened to know what you happen to know.<p>Personally, I'd rather have a not-so-educated assistant who would bash and slash and mash away at a problem until he understood it and solved it, than one who could simply reiterate what he'd learned, but could not or would not really analyze the problem in depth.<p>After all, even a horse can be trained to "count" to five.<p>[ January 30, 2005: Message edited by: terri ]</p>
terri wd0edw

User avatar
MrAl
Posts: 3862
Joined: Fri Jan 11, 2002 1:01 am
Location: NewJersey
Contact:

Re: electronics knowlege at BSEE level

Post by MrAl » Sun Jan 30, 2005 4:21 am

Hello there,<p>I think that many will be able to do the
filter design without any trouble, but i would
bet most dont remember the difference between
a 'half adder' and a 'full adder'. Perhaps
remind them what that is.
Remember that someone on the job probably has
access to the internet, reference books, etc.<p>
Here's one that stumps most of them...
can you find the answer?<p>Given three inputs i1, i2, i3
generate three outputs that are the exact
complement of the three inputs so that<p>o1=not(i1)
o2=not(i2)
o3=not(i3)<p>Sounds easy, and it is, if you're allowed to
use three inverters. The three inputs get
inverted using the three inverters and you're done.<p>Too bad that's not the case :-) You're only
allowed to use two inverters (yes, that's only
TWO (2) inverters, not three (3) ), but you're
allowed to use as many AND and OR gates as you
would like.
The three outputs have to generate the
complement of the three inputs exactly as three
simple inverters do, but without using any more
than two inverters and as many AND and OR gates
as you like.<p>This is not a trick question either!<p>
Good luck!
Al
LEDs vs Bulbs, LEDs are winning.

alby
Posts: 10
Joined: Sun Jan 30, 2005 1:01 am
Contact:

Re: electronics knowlege at BSEE level

Post by alby » Sun Jan 30, 2005 4:23 am

I teach both, Electrical Engineering and Electrical Engineering Technology at a large university (that used to have a winning football team).<p>The BSEE program that we teach is highly theoretical with very abstract concepts, lots of high-level math and a minimum of hands on experience.<p>The BSEET program has only the math requirements needed at each step of the process and lots of design and hands on experience.<p>I believe that for the requirements you are asking, you would have much better results interviewing graduates of a BSEET program.<p>Al

cato
Posts: 366
Joined: Sun Sep 07, 2003 1:01 am
Contact:

Re: electronics knowlege at BSEE level

Post by cato » Sun Jan 30, 2005 6:42 am

There was almost no lab or design work in my BS curriculum. I probably would have been able to draw you an RC filter and talk about 1/RC as the time constant. The half adder was probably covered in my sophomore year and so, I would have been fuzzy about that.<p>All that said, I think the kid that can answer your questions is the one you want to hire. He/she is clearly the one that loves electronics and has been working with these concepts on his or her own.<p>Your problem is that Everyone is looking for that kid. You're competing with HP, TI, IBM and Graduate School for that kids time. Good Luck<p>Maybe you should look for an older engineer, that has been used up and spit out of the corporate system as out of date, or too expensive.....

User avatar
philba
Posts: 2050
Joined: Tue Nov 30, 2004 1:01 am
Location: Seattle
Contact:

Re: electronics knowlege at BSEE level

Post by philba » Sun Jan 30, 2005 9:14 am

A lot depends on what you are looking for. I have recruited for Smart, Creative and Energetic engineers. Those are things that cant be taught. If I start with good material, the rest is a lot easier. So that's what I grill them for.<p>Over 25 years, I have interviewed several hundreds of college grads for entry level engineering positions. What I like to do is ask questions that demonstrate the thinking process, not rote knowledge. I agree that the questions you pose are thinking ones but could require a bit too much recall of specifics. Specifics that can be gotten from a book so it may not be a good test of their design skills. The real test is do they understand how to take the formulas and apply them to a real problem.<p>As an example, one of my favorite questions for software engineers was to design a quadrature encoder in software. The output should be the direction of rotation - CC or CCW. I describe the set up, let them position the sensors and so on. There are many ways to solve the problem and the process they take in getting there tells me lots about their thought process. There are a lot of problem you can pose that will let you inside their heads. I like problems that you can add complications to as they solve them to see how well they handle changes.<p>Another approach I like a lot is to discect a project they have done. I ask them what was their best project and then drill down on it. What did they do? Why did they do it the way they did? What was hard, easy? How would they do it differently? <p>I will eliminate any candidate that can't come up with ways they could have done it differently - good engineers are ALWAYS thinking about how to improve their project. Also, I take a dim view of candidates that can't recall details of their best project - either they have a lousy memory or didn't do as much as they claim.<p>Phil

L. Daniel Rosa
Posts: 400
Joined: Tue Dec 25, 2001 1:01 am
Location: Bellingham, WA
Contact:

Re: electronics knowlege at BSEE level

Post by L. Daniel Rosa » Sun Jan 30, 2005 10:02 am

I can make the half adder with one AND and one XOR, but not an inclusive OR. Did I misread the question?

Enzo
Posts: 276
Joined: Tue Sep 14, 2004 1:01 am
Location: Lansing, Michigan, USA
Contact:

Re: electronics knowlege at BSEE level

Post by Enzo » Sun Jan 30, 2005 11:26 am

I used to do a lot of digital control design, but I don't recall off the top of my head what exactly half adder means. I might even be using one at the moment.<p>What do you want these people for? A degree means you have studied the material, but have no practical experience. They either have to work and get that, or you have to provide it. I have studied many things over the decades, but I would have to bone up on much of it if quized. Certainly anything to do with RF would be forgotten. Of course these days I am solid with vacuum tubes. WHo knew?<p>I agree with Philba. I would rather hire someone who can use his head and hands rather than someone who can design a circuit but couldn't build it or find it on a board. I hire technicians, not engineers, so my needs are maybe different.<p>Absolutely the first thing I ask a candidate is to read the color code on a resistor I hand him. But much of my interview revolves around my trying to see how curious the guy is and how he thinks about things. How deeply does he think about things. WHen I walk onto an airplane, I am not simply going to my seat, I am checking out how the hinge is made for the door, and the construction of things. I am checking out technologies I don't see every day. I want a guy like that. For a tech job, I think I would rather have the self taught guy who has been fixing things in his basement for a year than the kid right out of an associates degree program. AT least the basement guy knows how to take something apart. I will teach the tech what he needs to know for the job if he has the basic understanding of electronics.<p>I want to know what a guy is interested in. He might be into electronics or computers, and if so I want to know if he really cares what is inside and what it can do. Maybe electronics is his job, but he really likes model railroads or maybe motorcycles. OK, is he really into it, or is it just a merit badge. I want to know if he has thought about the various ways of making tiny trees for his train, or if he really knows much about his bike.<p>You are hiring his head, not his resume.<p>When I was in school we had to remember formulae and stuff. Nowdays they allow crib sheets, because it is not so important that you can learn some lengthy formula as it is you know which formula to use and when. Your green school grads have everything stored in their heads as lessons they had. it will come back if they look at it. Real world experience makes the difference.<p>ANd why not consider out of work older engineers. SOme might not want to work at entry level salary, but others just want to be out there doing the work. DOn't hire the ones demanding big salaries. Hire the ones that want to do the job.

jimandy
Posts: 570
Joined: Sat Dec 04, 2004 1:01 am
Location: Birmingham AL USA
Contact:

Re: electronics knowlege at BSEE level

Post by jimandy » Sun Jan 30, 2005 2:19 pm

For a quick test on the digital side I would have the candidate write out the truth tables for the primary logic units: "and", "or", "xor". If he (she) doesn't understand truth tables they'll have serious problems in digital design,
"if it's not another it's one thing."

rocket scientist
Posts: 25
Joined: Mon Jan 03, 2005 1:01 am
Location: san diego
Contact:

Re: electronics knowlege at BSEE level

Post by rocket scientist » Sun Jan 30, 2005 10:46 pm

All of the above feedback is very useful. Sounds like you guys would make great interviewers. I will try to incorporate these ideas in the next round. Thanks.

Bernius1
Posts: 349
Joined: Sat Sep 21, 2002 1:01 am
Location: NY
Contact:

Re: electronics knowlege at BSEE level

Post by Bernius1 » Mon Jan 31, 2005 3:03 am

R.S., I had to post; couldn't resist (pardon the pun !).
I'm an unedumacated hobbyist, who rediscovered electronics about 18 months ago. I'd take a minute on the half adder, but I'd get it.
I say your questions are not overboard. An engineer supposed to be making you money should also know what a Karnaugh Map is. And he should be able to describe the difference between Chebyshev , Sallen-Key, and Bessel filters with pros & cons. And he(she) should know why a 2nd/3rd/4th order filter is so named (not to mention 'T' and 'pi' filters !). What trade magazines do they subscribe to ? What problem are they now tackling ?
If you saw my 'overdrive' post, you caught me amidst my fumbling. As it turns out, the ckt is a LOG amp, where the feedback loop is self-overdriving, operating in common base mode. I chose cap's on the bases to act as a zero-crossing-, or slope-change- detector, because I want the distortion to always be a harmonic of the input signal. When I get it right , I'll post the schematic. After that, my next paper tiger is a cascading RF comb filter, like a sniffer, to quickly give the strongest local signal. Should be a textbook 'op-amp-cookbook' design with a few comparators. (And VAKITS.COM has SMT IC kits for $9.99 !!) Why belabour the point ? Because if a sofa-spud ( couch potatoe ) like myself can envision and pursue these things, then EVERY BSEE should. Just an opinion.
Thanks....George
Can't we end all posts with a comical quip?

JB-82-Delft
Posts: 9
Joined: Wed Jan 19, 2005 1:01 am
Location: Delft
Contact:

Re: electronics knowlege at BSEE level

Post by JB-82-Delft » Mon Jan 31, 2005 5:22 am

1st year knowledge here...

rocket scientist
Posts: 25
Joined: Mon Jan 03, 2005 1:01 am
Location: san diego
Contact:

Re: electronics knowlege at BSEE level

Post by rocket scientist » Mon Jan 31, 2005 6:57 pm

Hi no_vice<p>These kids out of college are not even close to what you are talking about. I think the reason is that electronics was never their hobby. As a result they have no experience going into school, and almost none coming out. Also, EE is now a profession that is all over the map, and I would guess electronics is a small fraction of what they study. They study things like learning machines, optimal signal processing, pattern recognition, Bayesian methods, likelihood prcessing, neural networks, software engineering bla bla bla, and probably have very little time left for the electrical or the engineering stuff.

Post Reply

Who is online

Users browsing this forum: No registered users and 35 guests