Monthly Archives: June 2017

My New Cabin Construction

A number of folks have asked that I post pictures of my cabin construction project. The project actually consists of two separate activities: a large garage (started last fall) and a two-story cabin. I will start posting photos here as things progress. Continue reading

 
Posted in Construction, Personal | 4 Comments

Analysis of 555-Based PWM Circuit

I received a request for the design formulas that can be used to estimate the frequency (f) and duty cycle (DC) generated by the 555 timer-based Pulse Width Modulator (PWM)  circuit shown in Figure 1. The presence of diodes in the charge and discharge paths are the main cause of the confusion. Continue reading

 
Posted in Electronics | Leave a comment

Visualizing US vs IJN Aircraft Carrier Numbers During WW2

I watched an interesting lecture on American History TV this weekend called Japanese Perspective on the Battle of Midway by Anthony Tully. The most interesting part of the discussion occurred when Tully began showing how the US production of aircraft carriers eventually overwhelmed the Japanese ability to build carriers. He used some simple graphs to show the relative carrier strength of the US Navy versus the Imperial Japanese Navy (IJN) over time. In this post, I will come up with my own graphics to visualize this information. Continue reading

 
Posted in History Through Spreadsheets, Military History | Leave a comment

Coal Production By State

I have been listening to politicians discussing US energy policy the last few days. Very few facts were presented during these discussions, but one politician did casually mentioned that Wyoming produces more coal than the next six states combined. I did not know that Wyoming was such a dominating coal producer, and I began to look at how to fact check this statement. Fortunately, the US Energy Information Administration (EIA) has all the data readily available from this web page. Continue reading

 
Posted in Fact Checking | 6 Comments