MWagner_MA

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Sr. Electronics Engineer

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MWagner_MA

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  • 01.16.2018
  • Teardown: A better Chinese 12V adapter
  • Hi Mike, yeah in-spite of the weird name they make some very reliable power supplies. I work for a medical test equipment firm and have first hand knowledge of that over the last 6-years. Typically metal cased supplies, AC-DC, in the 24V/250-300W range, and a few thousands units per year.
  • 01.01.2018
  • Avoiding blood pressure measurement errors
  • Yeah, definitely an instrumentation error. I would have the doc take a reading conventionally, then use my cuff. At this point, I only trust readings taking in a doctors office by trained staff. Once these vendors need to get approved by insurance, then I suspect the accuracy will improve, because they would be liable for a lawsuit then.
  • 01.02.2018
  • How long should T&M gear be supported?
  • I expect to use test equipment for AT LEAST 10yrs. An oscilloscope is a "fundamental" measurement tool that doesn't really go obsolete. We have several Agilent scopes that are 6+yrs old and expect to continue to use them for another 4-5yrs+. People forget the days of Hewlett Packard where instruments that were 10yrs old were purchased on the used market and used for another 10yrs! I have a multi-meter that is 30yrs old and is as accurate as the day I bought it! 3yr life is WAY too short.
  • 01.01.2018
  • Avoiding blood pressure measurement errors
  • John, I would be interested in hearing your experience with the accuracy of such devices. I gave up trying after (2) devices almost never matched what was measured in the doctors office. So clearly there is much work to be done in this sensing area to bring the accuracy more in-line with conventional methods. I tried AND medical and Microlife from Costco, both had errors as much as "30" counts which is very high considering a "good" number is 120/70
  • 01.03.2018
  • A lifetime designing PCBs: Focus on functional specs
  • I don't know what you are talking about. What I consider a "good design practice" allows creative talent to contribute, and adjusts requirements as needed during the projects I have worked on. It boils down to have the right talent in the right places (customer facing, systems engineering, device engineering). The "golden spec" is a myth. Put the wrong people in, and any design process will fail. Use what ever process if more efficient for the team.
  • 01.03.2018
  • A lifetime designing PCBs: Focus on functional specs
  • I've enjoyed your series so far Charles. Functional specs are so important especially as companies may be trying the "Agile" development technique, what I consider "trial and error". (not my idea of a good time) I still believe it is better to spend a little time up front and think a bit first before jumping into a task and thrashing or worse "this is what we have done before"...keep the articles coming Charles.
  • 12.19.2017
  • Thoughts on the circuits you should publish
  • Thanks for the kind words Steve. The part I didn't comment on is that I don't agree a reason for the questionable quality of some articles is NOT due to the caliber of editors at Aspencore as is the time to review deeply technical articles and the desire to keep material fresh and spur discussion. Your background at Burr Brown and TI is enough to get my attention as a reputable engineer. I started my analog career designing in Burr Brown parts and now TI is one of my "go to" vendors for such parts. Happy Holidays Steve.
  • 12.19.2017
  • Thoughts on the circuits you should publish
  • Jerry, well done. Now, more than ever it is "let the buyer beware", or in this case the reader. I always advise junior engineers, don't use another engineer's circuit unless you either a. know the reputation of the designer, or b. take the time to understand the circuit fully. Early in my career I got 'hosed' by problem designs. No offense to university professors, but circuits offered by them are suspect from the start as their career path didn't involve designing for production, rather they have been doing it to teach or for research. These are very different paths requiring different skill sets that are developed over time.
  • 12.13.2017
  • Sensing body dehydration
  • It looks like your signal-to-noise (or delta between hydrated and de-hydrated) is too high to be really useful. You might want to consider some analog processing with low Voffset op-amps to get better data, buffered, then feed that into the microcontroller.
  • 11.10.2017
  • Are “beam array” headlights in automotive’s future?
  • I understand that it may not be 1:1, but it will certainly have more elements than current designs. I'm just tired of people saying "gee wiz, look at this!", and having it last only 2yrs. We can't even make microwave ovens anymore...our current GE was at first DOA, then the current one no longer has under-unit lighting..dead... in less than 2yrs. I'm glad GE doesn't build automotive lighting! (I hope :-))