Category Archives: Electronics

Motion Picture Aspect Ratios

Posted on 17-March-2015 by mathscinotes

I love old movies and one of the best is The Quiet Man. I recently picked up the Blu-Ray version and watched it with my wife this weekend. During the movie, my wife asked about the movies aspect ratio – it is not a widescreen movie. The Quiet Man was filmed in Academy Ratio (1.37:1), a ratio which was standardized by the Academy of Motion Picture Arts and Sciences in 1932. The Quiet Man was released in 1952, a year before the mass introduction of a plethora of widescreen film formats. Continue reading →

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Designing an LED Backlight

Posted on 16-February-2015 by mathscinotes

I was reading an application note by Texas Instruments yesterday on how to design an LED backlight for an LCD display (Figure 1). The article was interesting, but it did bother me because it presented a rather involved formula and did not provided any motivation for the formula, a derivation, or even definitions of the parameters used in the formula. Continue reading →

Posted in Electronics, optics | 3 Comments

Beautiful Spiral

Posted on 14-January-2015 by mathscinotes

Quote of the Day If a mistake is not a stepping stone, then it is a mistake. — Eli Siegel, "Damned Welcome" I have always been amazed at the beautiful curves that relatively simple functions can generate. I saw this … Continue reading →

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Clever Use of Different Solder Melting Points to Solve a PCB Problem

Posted on 8-January-2015 by mathscinotes

Just before lunch, some of the hardware folks here were having a discussion about a Printed Circuit Board (PCB) issue that had come up and how we had solved this issue in the past. During this discussion, one of the hardware managers reminded me of how he cleverly resolved a part problem we had a few years ago by using solders with different melting points. At the time, I thought his solution was brilliant and it saved us a bunch of time and money. His solution is worth documenting here. Continue reading →

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Unit Conversion and Significant Digits

Posted on 7-January-2015 by mathscinotes

Quote of the Day Negative results are just what I want. They're just as valuable to me as positive results. I can never find the thing that does the job best until I find the ones that don’t. — Thomas … Continue reading →

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Optimum Television Viewing Distance

Posted on 5-January-2015 by mathscinotes

Quote of the Day I am not a fast reader, I am a fast understander. — Isaac Asimov Introduction My wife has said that we are going to move into the 1990s and buy a High-Definition TV (HDTV). I am … Continue reading →

Posted in Electronics | 3 Comments

Industrial Design Sometimes Defies Logic

Posted on 2-December-2014 by mathscinotes

I just had one of those moments when my entire career flashed before my eyes – I hate when that happens. We have worked hard to make sure that our wireless products have only internal antennas because our product design experts said that we needed a "clean" external design. That means no external antennas sticking out. As part of this design effort, we have become very good at making internal antennas perform about as well as external antennas. Continue reading →

Posted in Electronics, Management | 2 Comments

Estimating the RMS Ring Voltage at a Telephone

Posted on 11-November-2014 by mathscinotes

Introduction I just saw a customer report of phone ringing issues with an old 2500 series phone (Figure 1). While these are good phones, they can be difficult for Fiber-to-the-Home (FTTH) deployments because they have 1 Ringer Equivalence Number (REN) … Continue reading →

Posted in Electronics, Telephones | Comments Off on Estimating the RMS Ring Voltage at a Telephone

Interesting Discussion on Lithium Battery Fire Hazard

Posted on 21-October-2014 by mathscinotes

We have all heard stories of the  fire hazards that lithium-ion batteries present – just to remind you, here is a partial list: Boeing Dreamliner Electric Cars Samsung Phones There have been many other documented "thermal events". I personally have … Continue reading →

Posted in Batteries, Electronics | 1 Comment

Network Data rates: Advertised Versus Actual

Posted on 20-October-2014 by mathscinotes

Introduction I often get questions from customers on what data rate can they expect from their particular network protocol, like Ethernet, MoCA, or HPNA. They often have expectations that have been set by marketing material and not reality. I thought … Continue reading →

Posted in Electronics | 1 Comment