Tag Archives: electronics

Battery Freezing Math

I live in a cold climate -- so cold that under certain circumstances we can freeze our lead-acid batteries (Figure 1). A customer who lives in my region called recently and was wondering if I thought any of his batteries would have frozen over the winter. A number of his Internet service subscribers have vacation homes that are unoccupied over the winter. All of these vacation home owners turn off their AC power for the winter. Since all of our Optical Network Terminals (ONT) are connected to Uninterruptible Power Sources (UPS), they will begin operating off of their battery when the AC power goes away. If the home owner does not disconnect the battery, the ONT will run discharge the battery. This is important because a discharged battery will freeze -- a charged battery will not freeze. A battery that has been frozen is very likely a dead battery. Continue reading

 
Posted in Batteries, Electronics | Tagged , , | 13 Comments

Computer Museum in Bozeman Montana

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

Quote of the Day Life isn't about finding yourself. Life is about creating yourself. — George Bernard Shaw:" Introduction I deal with a lot of battery issues. Our products generally ship with an Uninterruptible Power Supply (UPS) that contains a … Continue reading

 
Posted in Electronics | Tagged , | 8 Comments

Potentiometer Math

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 , | 14 Comments

Measuring the Ring Voltage on a Telephone

Quote of the Day Money can't buy happiness, but it can make you awfully comfortable while you're being miserable. — Clare Boothe Luce Introduction I received an email yesterday from a sales engineer who was having difficulty measuring the ring … Continue reading

 
Posted in Electronics | Tagged , , | 15 Comments

Another Interview Question

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 , , , , | 1 Comment

The Capacitor Puzzle That Got Me My First Job

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 , , , | 20 Comments