Tag Archives: electronics

Battery Freezing Math

Posted on February 26, 2013 by

Introduction I live in a cold climate — so cold that under certain circumstances we can freeze our lead-acid batteries. A customer who lives in my region called recently and was wondering if I thought any of his batteries would … Continue reading →

Posted in Batteries, Electronics | Tagged , , | Leave a comment

Computer Museum in Bozeman Montana

Posted on May 25, 2012 by

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

Battery Self-Discharge Math

Posted on April 3, 2012 by

Introduction I deal with a lot of battery issues. Our products generally ship with an Uninterruptible Power Supply (UPS) that contains a 7.2 A-hr Sealed Lead-Acid (SLA) battery. I occasionally hear customers say that we shipped them bad batteries. Since … Continue reading →

Posted in Electronics | Tagged , | 2 Comments

Potentiometer Math

Posted on December 22, 2011 by

Introduction I have an application where a potentiometer may be useful. In fact, it would be useful if the potentiometer had a logarithmic resistance characteristic, which is also called an audio taper for reasons that I will cover later. I … Continue reading →

Posted in Electronics | Tagged , | 4 Comments

Measuring the Ring Voltage on a Telephone

Posted on November 8, 2010 by

Introduction I received an email yesterday from a sales engineer who was having difficulty measuring the ring voltage on one of our telephone circuits. The numbers he was getting did not agree with what my engineering group had measured. The … Continue reading →

Posted in Electronics | Tagged , , | 5 Comments

Another Interview Question

Posted on July 25, 2010 by

Besides me, there is one other engineer in my group that used to work for Hewlett-Packard back in the old days. One day we decided to compare notes on the crazy interview questions that we were asked all those many … Continue reading →

Posted in Interviewing, Problems | Tagged , , , , | Leave a comment

The Capacitor Puzzle That Got Me My First Job

Posted on June 25, 2010 by

In the spring of 1979, I was a soon-to-be-graduated electrical engineer that needed a job. As with other young engineers, I started to look for work during my last semester of school and I got a few nibbles. The most … Continue reading →

Posted in Interviewing, Problems | Tagged , , , | 6 Comments