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Category Archives: Electronics
Handling "Hot" Electronics Requires Gloves
I have had a number of equipment installers contact me this summer and express concerns about the temperature of the outdoor electronics that they are handling. In some cases, the electronics is too hot to hold. In every case, the … Continue reading
Some Empirical Potentiometer Results
Just a note that I have added some empirical test results to the following three posts on potentiometers. "Logarithmic" approximation using Linear pot with shunt resistances Square law circuit Opamp-based circuit
Posted in Electronics
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Cost of Cooling Electronics
Introduction One of my favorite physicists stopped by today and wanted to talk about the cost of cooling electronics like fans and air conditioners. The talk was somewhat mathematical and worth discussing here because the basic math is what a … Continue reading
Posted in Construction, Electronics
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Yet Another Circuit with a "Logarithmic" Characteristic
Introduction While I was looking for different circuits that generate a logarithmic characteristic (voltage, current, or resistance), I stumbled upon a web page that discussed a logarithmic potentiometer approximation using a linear potentiometer with one or two resistors connected to … Continue reading
Wall-Wart Math
I have had some questions recently on the power conversion efficiency of AC power adapters (aka "wall warts"). I think my customers are becoming more concerned about energy costs. The questions that I received focused on how the efficiency of … Continue reading
Posted in Electronics
2 Comments
Square Law Potentiometer Circuit
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
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
High Definition Television Bandwidth and Compression Math
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
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
Posted in Electronics
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Interesting Ratiometric Temperature Measurement Approach
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