A friend who works at a startup was recently explaining that the company’s biggest problem at the moment is its inability to find suitable engineering talent.
As a barometer, one of the "questions" it poses to interviewees is this:
You have a 10V ideal voltage source in parallel with a 5Ω resistor. What is the impedance?
So far, no one has answered correctly. (The answer is provided at the end, in case you want to take a shot at it.)
My friend says, “Engineering students today can't answer basic engineering questions. And we aren't talking about tier 2 or 3 universities, either.”
She tells the story better than me, so here are her words:
This is a well-known problem, one which I have discussed/commiserated with friends from two other firms with the same issue. One is in Massachusetts and the other is in Texas, so clearly this isn’t just a regional thing.
When you look at these people's resumes, all is sunshine and rainbows. When you ask them questions about their accomplished projects, it becomes clear that they have no clue what these so-called projects were really about. They can't answer. And not just undergrads; we rarely interview undergrads. We are talking about folks with MSs and PhDs.
Some are specialized to the point of absurdity, which I suppose makes some sense if you are going to be writing a thesis, but because they lack basic understanding of the underlying physics, they really don't know their specialties all that well, either. Plus, many have difficulty communicating in English.
The bottom line is that the schools are to blame. They should not be graduating people who do not understand the material they were taught.
She went on, including what she considered unrealistic salary expectations, but you get the gist of it. Are you seeing a similar situation out there? Tell us about it in the comments section below.
Spoiler alert: The answer to the question is 0. It's a trick question. The amount of the voltage is irrelevant. The key phrase is "ideal voltage source." The real purpose was to see if they knew what an ideal voltage source was.
Dave, missing a single question like this may not mean that an applicant is unqualified or incompetent. After all, everybody tends to be just a little nervous during an interview. On the other hand, repeatedly failing to notice significant details before claiming to solve a problem (the classic "Ready! Fire! Aim!" sequence)) certainly should raise a red flag about whether an applicant will be a net gain or net loss to the team.
It's been more than a quarter of a century since my engineering student days ended far short of graduation, but seeing a question about a circuit consisting of 2 devices in parallel was enough to make me stop and think "Wait a minute!" instead of "Too easy!" If I consider my knowledge of circuits to be not much better than an electrician's apprentice, what should I demand from folks who are applying for a position which will require them to identify and solve much more nuanced problems than this?
And one more thing, before I'm distracted again (I have my IT hat on tonight doing server maintenance and I'm writing while monitoring update installations).
The engineers and managers in the example are poster children of why hiring morons is bad for business. I told them. I sketched on the white boards. I showed excel charts of test data and they just stared vapidly. I did everything short of beating it into their thick heads with a bat and they never understood. They could not grasp why one couldn't use banana plugs and 18AWG wire for 160A. They failed to start early to counter the longer lead times of the wire, connectors and high-power test board components. With the professional ones, the shortcomings were surmountable through teamwork. But half were too inept even for that. They're precisely the kinds of people the trick questions are devised to root out.
Steve Jobs had interesting terminology for the flood of such people that inevitably pours into a company as it ages; He called it the "bozo explosion". Get the first few in, interview standards decline and in they all pour. Then the company fails in buiness.
Hi Dave, One never asks a single question in an interview. Instead, there is a pattern of questions to assess... 1.) How the candidate thinks, 2.) What the candidate knows. The trick questions are one quick and effective means of differentiating people who think from the rote memorization robots.
In the long run, how the college educated candidates think is more important than what they know -both for the company and for themselves. The university provides both candidates with basic training. Beyond that, I have the competency to train either candidate in what I need them to know. But the independent thinker will grow beyond the training and achieve success when faced with new problems but the rote memorization robot won't. And, the robot is at a career disadvantage because 9/10 engineering managers DON'T have the competence or patience for training.
Ultimately, the distinction is intellectual discipline vs. intellectual laziness. Like a virtuoso musician or professional athlete, the thinker takes initiative to maintain an intellectual edge through constant study, review and practice. Excellence is a disipline.
The question is really very simple and there is no excise for an EE missing it. Upon missing the second question of that nature, the job opportunity is lost. Sorry, but its like a car mechanic not knowing what tool removes an oil filter, or an accountant not being able to add -it betrays a fundamental deficiency in the skills of the trade.
BTW, I'm not Rich's contact. I'm just a random Silicon Valley Analog/Power Temp Engineer with prior experience founding a couple of startups.
@PwrGeek: How confident are you that success on a single question like this is an accurate predictor that a candidate won't make the kind of mistake you describe? In my opinion, it's a weak indicator, at best.
The engineers in your example were aware of the test current shift in the 1A product, but they didn't think through what it would mean for the 40A product. Apparently, nobody asked them, and they didn't ask themselves. So it seems that it was a failure of imagination (at a forehead-slappingly basic level), not a failure of knowledge.
I think you'd be more likely to identify candidates who would be successful in this sort of situation by paying attention to what questions they ask, rather than how they respond to your questions.
Obviously, nobody is arguing that you should hire mediocre people. But "smart" and "clever" are not always the same thing. Asking trick questions helps to determine which candidates are clever. Listening to the questions candidates ask helps to determine which ones are smart.
Hi Ken E, good questions. The practical characteristics and skills these kinds of trick questions demonstrate are the tendency and ability to solve problems from clearly understood root principles. In an R&D setting, thats precisely the kind of guy to hire because he'll be faced with weird and unprecidented problems on a daily basis.
Basically, if the candidate can't handle this itty bitty simple ideal trick question, then there is no way he'll achieve excellence in an R&D setting where he'll be faced with tougher, more complicated curveballs in the real and much more messy world.
About a year ago, I watched a major R&D project fail and burn-up a pile of money because it was staffed by precisely the kind of engineers and managers that fail this kind of trick question. A first 1A version of the product had a 4x shift in the test current to 4A from 150C to -55C. Nobody was capable of thinking through that the 40A version would require a test current of 160A at -55C. This is just one example of the many areas where the team fell down in elementary ABC engineering tasks because the company hired mediocre people.
What the trick questions do is to screen out the medicre candidates early in the interview process so one can conentrate the on-site interviews on the really good people.
Sorry if this sounds elitist but hiring is like picking people for a neighborhood softball game -the best and brightest get picked first because one is playing to win. The difference is that the stakes are higher because if the company looses then all the employees lose their jobs.
PwrGeek and richnass, neither of you explain how an answer that 'no one' has gotten right is illuminating, or weeds out anyone. It weeds out everyone.
Niether has explained to this novice either, how a 'ideal' circuit with an impedence of zero demonstrates engineering practicalities, and that's what you hire for.
I disagree. Its a good weeder question that culls out the mediocre 90% that don't think. Another one along the same lines it a current source into a capacitor. The non-thinking people will draw an exponential curve from rote memory.
The people who fail those kinds of questions have weak independent thinking skills. Yes, a savvy manager can train them. But they will never excel on their own. In an R&D environment that requires creativity, resourcefulness, analytical refinement and the ability to think independently, they will never be more than mediocre. The design won't be right. They won't catch the bugs. The product will fail on the market. And the company will lose business.
Even worse, when they advance into management, they'll really mess things up because they'll direct business impulsively based on intuitive presumption instead of on disciplined analysis of facts.
I got the answer right and in 2 seconds. Its obvious.
I went to a career fair here at the university. Was starting to talk with one recruiter about their jobs offerings. The second question they asked was 'What's your GPA?' I told them, 2.97. He looks at me and says, 'We require at least 3.0.' I added, I got 2.97 while working full time!' They didn't care. So, they may have lost out on a good opportunity because a GPA was 0.03 too low. Oh well!
To be fair, this question was not used as the "should we or shouldn't we" hire this person. It was just one of many, many questions that the candiates were asked.
As the author notes; "So far, no one has answered correctly." So what is the value of the question, other than feeding the ego of the questioners?
To then tie such a useless question to the state of education, hardly strikes me as sound engineering on the part of the many people dissing modern education here. A statistician would laugh at this misdrawn conclusion.
I'm no EE, but my thought was immediately 5 ohms too. Seemed like a simple application of the impedence formula the total opposition to alternating current by an electric circuit, equal to the square root of the sum of the squares of the resistance and reactance of the circuit and usually expressed in ohms. If the 'total' opposition to current in a circuit with an 'ideal' power supply is zero, current is infinate. In this case, it's 2 amps, isn't ?
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