Monthly Archives: May 2012

Computer Museum in Bozeman Montana

Posted on 25-May-2012 by mathscinotes

I am currently in Bozeman, Montana, and I just took a tour of the "Museum of Modern Human Progress," formerly known as the American Computer Museum. I was with one of my sons, and the museum provided us a great … Continue reading →

Posted in History of Science and Technology | Tagged | 4 Comments

Square Law Potentiometer Circuit

Posted on 25-May-2012 by mathscinotes

I do not have an immediate need for a circuit that generates an output voltage proportional to the square of the potentiometer setting, but this circuit was interesting enough that I thought I would document it here. I found it while looking for a logarithmic potentiometer circuit. Continue reading →

Posted in Electronics | 5 Comments

Another Circuit with a "Logarithmic" Characteristic

Posted on 23-May-2012 by mathscinotes

Electronics is my profession and my hobby (along with mathematics). For a hobbyist project of mine, I need an amplifier circuit with a programmable gain that varies exponentially with the setting on a potentiometer. When I design a circuit, I usually begin my design effort with a web search. I do not like reinventing the wheel. I found an old EDN article that has an interesting circuit, but the figures are not visible. I will reconstruct the circuit here based on the text description and make a small modification that makes it a bit more appropriate for my application. Continue reading →

Posted in Electronics | Tagged | 7 Comments

High Definition Television Bandwidth and Compression Math

Posted on 15-May-2012 by mathscinotes

As part of my job, I actually encountered one person who regularly watches 14 simultaneous HDTV feeds. He is a stock trader who works out of his home. He was displaying stock data from multiple markets on multiple televisions. Think about it -- 14 · 20 Mbps = 280 Mbps of television being watched by one person. Continue reading →

Posted in Electronics | 9 Comments

Great Electronic Computer History Talk

Posted on 5-May-2012 by mathscinotes

I just watched a great lecture by George Dyson on the early days (WWII era) of computer development and some of you may be interested in this topic as well. Dyson shares many stories about the legendary names in computer science: von Neumann, Turing, Eckert, etc. Dyson also had a special guest speaker at his lecture, Akrevoe Emmanouilides, who was a secretary working on the team developing MANIAC, an early computer. She is great! Continue reading →

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Interesting Ratiometric Temperature Measurement Approach

Posted on 4-May-2012 by mathscinotes

As you can tell, I enjoy interfacing to sensors. Today, I was reading the usual assortment of engineering trade journals when I came across an interesting part from Lapis Semiconductor that is worth discussing here. It uses simple digital technology to make accurate resistor measurements. If you have a resistive sensor, it may be a good way to go. Continue reading →

Posted in Electronics | Tagged | 1 Comment

Pioneer Anomaly Resolution Chat

Posted on 3-May-2012 by mathscinotes

The Planetary Society has a wonderful audio program called Planetary Radio. For those of you interested in the Pioneer Anomaly and a suggested resolution, listen to this program. All sorts of reasons have been proposed for the odd orbital behavior of the Pioneer spacecraft and this one seems pretty reasonable. As with most things electrical, the bad behavior can be traced to the batteries ... Continue reading →

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