Category: Electronics

Dec 27 2014

Ammeters and Internal Resistance

Question: Based on your previous post regarding voltmeters and internal resistance, I can safely assume that an ammeter must also have some internal resistance. What effect does this resistance have on current measurements, and what resistance value would minimize any error it introduces to the reading? Answer: It is indeed true that an ammeter must …

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Nov 24 2014

Voltmeters and Internal Resistance

Simple resistive circuit with voltmeter

Question: Does a voltmeter have any internal resistance, and if so, what, if any, affect does it have on voltage readings? Answer: Even if you have no electrical experience at all, I would hope that your answer to the first part of the question was, “yes.” Otherwise this would turn out to be an incredibly short …

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Nov 15 2014

Euler’s Formula

Besides being an obvious lady killer, Swiss mathematician Leonhard Euler gifted the world with some pretty important mathematical concepts, notational conventions, and formulas. I almost feel bad about the fact that I couldn’t even spell his name correctly until I was well into adulthood. You are probably thinking, “Sure, he had a bitchin’ robe, and for …

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Nov 08 2014

Finally Bought an Arduino Yun

Anker Astro3

I’ve had my eye on the Arduino Yun since it came out, but between an Uno, a Duemilanove, and a handful of shields, I always had something to play with and hadn’t run into any limitations that justified picking one up at the expense of some other shiny, new toy. Last week, however, a perfect storm …

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Oct 19 2005

Cyborg Humidity Gauge

Bacteria

Nature.com has published an article about the work of Ravi Saraf, a chemist from the University of Nebraska, Lincoln and his student Vikas Berry in integrating living bacteria into an electrical circuit that is part of a humidity-detecting device. While there have been other instances of circuits built to react to microorganisms, this “cellborg,” as …

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