Ohm's Law Problem
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From: Jim Thompson on 15 Feb 2010 20:46 On Mon, 15 Feb 2010 20:36:31 -0500, Bitrex <bitrex(a)de.lete.earthlink.net> wrote: >Joerg wrote: >> Joel Koltner wrote: >>> "Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com> wrote >>> in message news:11sin51vdubl64ouhcgn3b2omf36q111in(a)4ax.com... >>>> Everyone is making it too difficult. Just write it down in sequence, >>>> the answer falls right out... >>>> http://analog-innovations.com/SED/OhmsLaw_SED_JustWriteItDown.pdf >>> >> >> Ohm's law? I thought that had been repealed ... :-) >> >> >>> That's the same as what I ended up doing (in the later part of my >>> post), except that you use "V3/100" rather than just "I" for the >>> current in the lowest resistor. :-) >>> >>>> At MIT, I was spared (*) from Guillemin's obtuseness, I had Harry B. >>>> Lee for passive circuit analysis ;-) >>> >>> I had a guy who was a pretty talented teacher (he'd won a couple >>> awards for it, and I found him quite understandable), although he had >>> little if any real-world design experience. >>> >>> I'd read some of Guillemin's book, and while I think the guy was >>> pretty darned sharp, I disagree with his notion that you have to have >>> an incredibly thorough understanding of network analysis down pat >>> before you can get useful circuit design or analysis done. ... >> >> >> Sadly, that's the kind of notion that drives potential EE candidates >> away, at least from analog. And now we have a serious shortage of those. >> They think they have to be a rocket scientists to be able to thrive and >> make money in analog. Which is wrong. I learned the majority of my >> skills by "winging it". IOW I built RF stuff before I knew squat about >> any of that. And it actually worked, some still does. >> >> Note to potential candidates: If an author or professor says something >> like what must have been stipulated in this book, that you must be a top >> notch network analyst, do not listen. It's much more important to >> experiment, experiment, experiment, get a "feel" for what works, _then_ >> dive into the theory. Not the other way around. Just my 2 cents. >> >> Whew. Now I feel better ... >> > >Here's a question I'd like an honest answer to: I've studied analog >design for a long time as a hobby, but I was never able to attend a >university program of study for it during my 20s due to a series of >illnesses, and having to work hard when I was well enough to stay >afloat. I'm now 30, and I'm fortunate to currently be in a stable >enough situation to attempt a degree. I love EE, and would like >to study it formally, but if the future is truly as bleak for US >engineers (particularly ones who who will be at least 35 before they >land their first job) I should probably really let that sink in before >starting. You'll never learn much about circuit design in a course. You'll learn some useful fundamentals. But to be a circuit designer take those fundamentals, and a compendium of circuits, like AoE, and ANALYZE them. (Be dubious of the explanations in books). UNDERSTAND WHY they work. THEN you can be a designer. I was tinkering with circuits (and FLAMING many) for years before I went off to MIT. Now I was lucky, landing at Motorola just at the bare beginnings of integrated circuits. I still learn something new every day. When that stops hopefully my heart will stop at the same time ;-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
From: Joerg on 15 Feb 2010 20:57 Bitrex wrote: > Joerg wrote: >> Joel Koltner wrote: >>> "Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com> wrote >>> in message news:11sin51vdubl64ouhcgn3b2omf36q111in(a)4ax.com... >>>> Everyone is making it too difficult. Just write it down in sequence, >>>> the answer falls right out... >>>> http://analog-innovations.com/SED/OhmsLaw_SED_JustWriteItDown.pdf >>> >> >> Ohm's law? I thought that had been repealed ... :-) >> >> >>> That's the same as what I ended up doing (in the later part of my >>> post), except that you use "V3/100" rather than just "I" for the >>> current in the lowest resistor. :-) >>> >>>> At MIT, I was spared (*) from Guillemin's obtuseness, I had Harry B. >>>> Lee for passive circuit analysis ;-) >>> >>> I had a guy who was a pretty talented teacher (he'd won a couple >>> awards for it, and I found him quite understandable), although he had >>> little if any real-world design experience. >>> >>> I'd read some of Guillemin's book, and while I think the guy was >>> pretty darned sharp, I disagree with his notion that you have to have >>> an incredibly thorough understanding of network analysis down pat >>> before you can get useful circuit design or analysis done. ... >> >> >> Sadly, that's the kind of notion that drives potential EE candidates >> away, at least from analog. And now we have a serious shortage of >> those. They think they have to be a rocket scientists to be able to >> thrive and make money in analog. Which is wrong. I learned the >> majority of my skills by "winging it". IOW I built RF stuff before I >> knew squat about any of that. And it actually worked, some still does. >> >> Note to potential candidates: If an author or professor says something >> like what must have been stipulated in this book, that you must be a >> top notch network analyst, do not listen. It's much more important to >> experiment, experiment, experiment, get a "feel" for what works, >> _then_ dive into the theory. Not the other way around. Just my 2 cents. >> >> Whew. Now I feel better ... >> > > Here's a question I'd like an honest answer to: I've studied analog > design for a long time as a hobby, but I was never able to attend a > university program of study for it during my 20s due to a series of > illnesses, and having to work hard when I was well enough to stay > afloat. I'm now 30, and I'm fortunate to currently be in a stable > enough situation to attempt a degree. I love EE, and would like > to study it formally, but if the future is truly as bleak for US > engineers (particularly ones who who will be at least 35 before they > land their first job) I should probably really let that sink in before > starting. For a good analog guy it does not look bleak at all. But as Jim pointed out you don't really learn much about real design in courses, you've got to do that on your own. The reason why I did my masters was so I'd have the degree in my hands. The only times I ever needed it was for visas from governments etc. Nobody else ever asked about it. How did I learn design? Mostly through the ARRL Handbook, cuts, bruises and umpteen spools of solder :-) -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Joel Koltner on 15 Feb 2010 21:13 "Bitrex" <bitrex(a)de.lete.earthlink.net> wrote in message news:bLGdna6-WNqGauTWnZ2dnUVZ_gqdnZ2d(a)earthlink.com... > I'm now 30, and I'm fortunate to currently be in a stable enough situation > to attempt a degree. I love EE, and would like > to study it formally, but if the future is truly as bleak for US engineers > (particularly ones who who will be at least 35 before they land their first > job) I should probably really let that sink in before starting. The future isn't bleak at all, IMO; electrical engineering jobs will continue to pay well above average for the foreseeable future, even if the jobs do become scarcer in the U.S. What kind of electrical engineering would you like to do? There are some areas where, OK, you really do need to be well-above-average in your intellect to make a go of things (people like Ulrich Rohde or Charles Wenzel definitely don't play with kids' gloves), but I'm convinced that for anybody who manages to make it through college with decent grades and a good understanding of what they were taught, your ultimate limitations usually tend to be largely self-imposed based on how much time and effort you're willing and able to put into self-study rather than your innate abilities. I would suggest that you take a few digital logic classes and a few programming courses -- there are TONS of jobs out there for anyone who can manage to write a little C code for a microcontroller or a little Verilog for an FPGA, and many of those jobs are fundamentally pretty easy; they can tide you over while you're figuring out what you really want to do and find yourself a job doing it. Objectively you may well be at a disadvantage from the twenty-somethings graduating with their BSEEs today, but keep in mind that of those kids, a very large percentage view engineering as just a 9-5 job and will never expend much if any effort outside of work to improve their skills. Your years of having electronics as a hobby will give you a leg-up here. ---Joel
From: RST Engineering on 15 Feb 2010 23:54 On Mon, 15 Feb 2010 17:57:57 -0800, Joerg <invalid(a)invalid.invalid> wrote: >For a good analog guy it does not look bleak at all. But as Jim pointed >out you don't really learn much about real design in courses, you've got >to do that on your own. The reason why I did my masters was so I'd have >the degree in my hands. The only times I ever needed it was for visas >from governments etc. Nobody else ever asked about it. > >How did I learn design? Mostly through the ARRL Handbook, cuts, bruises >and umpteen spools of solder :-) I just put the empty of my first spool of solder I used in RST Engineering in a jewel window case on the wall. It was on my very first RST project in 1973 and I opened my second one-pound spool on the replacement for that first product about a year ago. Of course, I may have used bits and pieces of other spools from time to time, but the date I wrote on that first spool is still valid ... Thanksgiving Day, 1973. As my brother the football star (and PhD economist) once noted, "Damned few like us, and none to replace us." Jim
From: David L. Jones on 16 Feb 2010 01:02
Jon Kirwan wrote: > On Mon, 15 Feb 2010 09:36:26 -0800, "Joel Koltner" > <zapwireDASHgroups(a)yahoo.com> wrote: > >> "Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com> >> wrote in message news:11sin51vdubl64ouhcgn3b2omf36q111in(a)4ax.com... >>> Everyone is making it too difficult. Just write it down in >>> sequence, the answer falls right out... >>> http://analog-innovations.com/SED/OhmsLaw_SED_JustWriteItDown.pdf >> >> That's the same as what I ended up doing (in the later part of my >> post), except that you use "V3/100" rather than just "I" for the >> current in the lowest resistor. :-) >> >>> At MIT, I was spared (*) from Guillemin's obtuseness, I had Harry B. >>> Lee for passive circuit analysis ;-) >> >> I had a guy who was a pretty talented teacher (he'd won a couple >> awards for it, and I found him quite understandable), although he >> had little if any real-world design experience. >> >> I'd read some of Guillemin's book, and while I think the guy was >> pretty darned sharp, I disagree with his notion that you have to >> have an incredibly thorough understanding of network analysis down >> pat before you can get useful circuit design or analysis done. >> Something like his "Introductory Circuit Theory" strikes me as a >> good graduate-level course! (Be weary of any book with the term >> "introductory" in its title...) >> >> My opinion here is that in the real world your approach or mine (or >> superposition if you insist) tends to be rather more productive and >> insightful than Jon's somewhat pedantic approach. As soon as you go >> down the path of, "well, this is how SPICE sets up the equations," I >> think you're largely giving up on gleaning insight directly from the >> equations themselves and have to run sweeps or Monte Carlo >> simulations to get some back. <snip> > > I actually take a very different view. And I'll tell you > why. When the infinite resistor grid problem showed up here > for the first time _I_ saw it (and it has, more than once, as > I participated in at least two such instances), the method > for setting up the closed solution integral as well as > forumlating a trivial numerical solution was obvious to me > _because_ of that "pedantic approach." It provides a very > broadly applicable method that applies across many fields and > provides a useful thinking tool that will serve well no > matter where you find yourself. It's much more fun to just built it and measure it: http://www.eevblog.com/2009/08/15/eevblog-25-the-infinite-resistor-puzzle/ Dave. -- ================================================ Check out my Electronics Engineering Video Blog & Podcast: http://www.eevblog.com |