# Monthly Archives: December 2010

## Dual Modulus Counter Design Example

Introduction One of the more common problems in the life of a digital hardware designer is to divide down a master clock to some desired lower frequency value. If life is kind, the master clock is an integer multiple of … Continue reading

## Little Stories from the History of Science and Technology

Introduction I have always been interested in the connectedness of people. The theory that each of us is separated by only six degrees from anyone else is a theory I like to test. If you examine things carefully, you may … Continue reading

## Test Time and Estimating Bit Error Rate

Introduction Test time is expensive. Since our products need to conform to industry standards for Bit Error Rate (BER), we need to test for BER. It is important that we test long enough to ensure that we meet the requirements, … Continue reading

Posted in Electronics, Fiber Optics | Tagged , , | 4 Comments

## Calculating the Earth’s Age

Introduction I have been listening to the audio book The Disappearing Spoon, which is an excellent tale about all of the elements of the periodic table. Of particular interest to me was the discussion of how geologists date the age … Continue reading

## Power Dissipated in a Maximum Phone Load During Ringing

I am writing a specification this morning and I realized that I have never calculated the maximum power drawn by a phone during ringing. I was surprised by the number – 3 W. This is a lot for unit that … Continue reading

## Thermal Runaway Model of Lead-Acid Battery (Part 2)

Derivation of the Output Power Equation The output power equation (Equation 3) is really a restatement of Newton’s law of cooling. Equation 3 states the battery’s steady-state power dissipation is a linear function of the battery’s temperature and the ambient … Continue reading

## Thermal Runaway Model of a Lead-Acid Battery (Part 1)

Introduction Very nearly every product we make ships with one or more lead-acid batteries. Since we have built hundreds of thousands of units, that is a lot of batteries. While most people encounter batteries everyday, few really understand the problems … Continue reading

Posted in Batteries, Electronics | 1 Comment

## Laser Failure Rate Estimate Example

Introduction I have spent some time lately talking to people about laser failure characteristics. Most electronic component reliability modeling is done using the exponential probability distribution, which assumes the components have a constant failure rate and there is no wearout … Continue reading

Posted in Electronics, Fiber Optics | Tagged , , | 2 Comments

## Calculating Drawer Heights

Introduction As you can tell from all the recent posts on construction, I am in the middle of planning some remodeling on my home. One of my projects includes designing a chest of drawers. It turns out that there are … Continue reading

Posted in Construction | Tagged , , | 6 Comments