# Monthly Archives: August 2015

## Why Use an Antilog Taper Pot?

I have received a number questions lately on the use of log and antilog taper potentiometers. Because of these questions, I thought it might be useful to review why these tapers are used. Continue reading

Posted in Electronics, General Science | 1 Comment

## Drying Up the Mediterranean

One of my favorite audio books is titled The Earth: A Very Short Introduction (link). This book provides an excellent overview of basic geophysics. It is not a book about rocks, but rather a book about the structure of the Earth. This book contains an excellent discussion of the Mediterranean's periodic drying episodes that are collectively known as the Messinian Event, which occurred five million years ago during the Miocene era. Continue reading

Posted in General Science, Geology | 1 Comment

## Sigmoid Potentiometer Taper

Yesterday, I had a question from a reader on how to develop mathematical formulas for different potentiometer tapers. Normally, I would simply answer the questioner without a separate post, but my solution for this particular question provided a nice illustration of basic coordinate transformations. Since I have not shown any coordinate transformation applications in this blog before, I thought it would be worthwhile to make a post of my response. Continue reading

Posted in Electronics | 4 Comments

## Electricity Generation Percentage from Coal By State

I drive a short distance (7 km) to work everyday. On my drive, I often have to wait at a railroad crossing for a coal-train train to pass (typical example in Figure 1). I have never thought much how much my state depends on coal until I saw an interview with a Missouri senator who was talking about her state's dependence on coal for electrical power generation. I am currently teaching myself how to use the Power Query add-in for Excel, and I thought that generating a graphic of coal dependence by state would be a good Power Query/Visio exercise. Continue reading

Posted in General Science, software | Comments Off on Electricity Generation Percentage from Coal By State

## How Many Red Blood Cells Do We Lose A Day?

I regularly visit the RefDesk website to pick up general information. Refdesk has a section that contains a Fact of the Day from the Random History website. Unfortunately, these "facts" are occasionally just plain wrong (example). Today, another one of these random facts did not seem correct and I thought I would perform a quick Fermi analysis here to show that it cannot be correct. I assume that they confused hours and minutes in their analysis. I will present my argument below. Continue reading

Posted in General Science, Health | 5 Comments

## Linking Data to a Visio Drawing

I enjoy collecting and occasionally creating pins for my Pinterest collection. There was one pin that I saw (Figure 1) that I thought would be a good exercise to use when I conduct training classes in Visio and Excel. This post will use a simple Excel table of planetary orbit data to drive the creation of similar graphic in Visio. I will make one change to the information contained in Figure 1 – I will add Pluto because I still like to think of it as a planet. I will also remove the black background because I find black a bit harsh for a background color. Continue reading

Posted in Astronomy, software | Comments Off on Linking Data to a Visio Drawing