Category Archives: Electronics

Russian Meteor Characteristics

Posted on 20-February-2013 by mathscinotes

A meteor exploded over Chelyabinsk, Russia (Figure 1), at 3:20 UTC on February 15, 2013. I have been reading accounts of the size, speed, and energy of the meteor. This post presents some simple calculations that verify the consistency of the expert's estimates on the meteor characteristics. Also, I thought it would also be interesting to look at the amount of overpressure required to cause the sort of damage that was seen after the meteor and to include some explanatory material as to how scientists determine the characteristics of a meteor. Continue reading →

Posted in Astronomy, Electronics | 1 Comment

Battery Outgassing Math

Posted on 12-February-2013 by mathscinotes

I recently have received a number of questions about the outgassing of hydrogen gas that can occur from lead acid batteries when they are being overcharged. I thought it would be useful to review what is happening when a battery is outgassing. When being charged, batteries can release enough hydrogen gas to create an explosive hazard. Consider this report and Figure 1 as an example as to what can happen. With lead-acid batteries, hydrogen gas can be generated any time, but charging is when the greatest challenges are faced. Continue reading →

Posted in Batteries, Electronics | 20 Comments

AC Backup Power Using A Simulated Sine Wave

Posted on 3-February-2013 by mathscinotes

Quote of the Day Whenever you want to marry someone, go have lunch with his ex-wife. - Shelly Winter Introduction A customer today requested an AC-output Uninterruptible Power Source (UPS) for our indoor Optical Network Termination (ONT) products. Product Management … Continue reading →

Posted in Electronics | 5 Comments

The Joys of Electrostatic Discharge

Posted on 7-January-2013 by mathscinotes

I had to laugh at this Youtube video this morning. This poor guy shows you exactly how NOT to handle hardware during ElectroStatic Discharge (ESD) tests. Continue reading →

Posted in Electronics | 3 Comments

Parabolas and Avalanche Photodiodes

Posted on 6-January-2013 by mathscinotes

During a meeting recently, a vendor was discussing the need for performing production calibration testing that required fitting a parabola to the data from an optical sensor called an Avalanche PhotoDiode (APD) (Figure 1). I recalled this comment while reviewing a test report this morning where I saw a parabola appear in an APD test report from an optical physicist in my group. I realized that our physicist and this vendor were working in related areas. It was an excellent test report that covered both the theoretical and experimental aspects of the subject. It also seemed like a good topic for this blog. Continue reading →

Posted in Electronics | Comments Off on Parabolas and Avalanche Photodiodes

Battery Failure Rates and Continuously-Compounded Interest

Posted on 2-January-2013 by mathscinotes

While performing some routine reliability analysis, I noticed that there is a similarity between battery aging and continuously-compounded interest calculations. I had not noticed this similarity before, and I thought I would document it here.

Figure 1 shows a common lead-acid battery. This chemistry is my focus in this post. Other chemistries will behave similarly, but the constants involved will differ. I will be assuming that the failure rate of the battery is described by the Arrhenius equation. Continue reading →

Posted in Batteries, Electronics | 1 Comment

Lead Acid Battery Life Math

Posted on 24-December-2012 by mathscinotes

Quote of the Day The key to effective goal-setting is being realistic about what you can accomplish. — Andrea Woroch Introduction It is difficult to dig trenches for fiber optic cable in many parts of the US and Canada during … Continue reading →

Posted in Batteries, Electronics | 2 Comments

Battery Charge Capacity and Energy Math

Posted on 16-December-2012 by mathscinotes

Introduction I am doing some requirements analysis work on backup power systems for GPON ONTs. As part of this work, I need to perform an evaluation of a number of batteries for charge capacity and energy. As part of this … Continue reading →

Posted in Batteries, Electronics | 4 Comments

Torpedo Data Computer Video

Posted on 9-December-2012 by mathscinotes

I am a fan of both naval history and the history of computing machines. I just saw a great video on the Torpedo Data Computer (TDC) that have I include here. The TDC was one of the last examples of … Continue reading →

Posted in Electronics, History of Science and Technology | 1 Comment

Network Cable Math

Posted on 6-December-2012 by mathscinotes

Introduction Today I'm going to be discussing ethernet cables and if you've been reading this blog for a while, you know I'm no stranger to ethernet problems. I work with it quite a lot at work so I'm familiar with … Continue reading →

Posted in Electronics | 7 Comments