Monthly Archives: May 2016

I have been designing circuits with resistors since I was a kid working on science fair projects – I still remember building my first Radio Shack photocell project. While I have always thought of resistors as simple devices, I recently discovered that I have been laboring under a misconception about the standard resistor values.

Until last week, I believed that the values of the E-series standard resistor values were selected to ensure that if I needed a resistor within x% of a specific value, I simply needed to choose a resistor from the x% tolerance set. For example, Figure 1 shows the E12 series (i.e. ±10%) values – notice that each tolerance range overlaps the adjacent ranges. This means that you can always find an E12 resistor value within 10% of your required value. Continue reading →

I recently was asked by some staff members to describe the key variables that drive integrated circuit costs. To answer the question, I decided that the best approach was to prepare a spreadsheet that includes all the critical parameters along with some computational examples – people can try different parameters and determine the critical cost sensitivities on their own. Continue reading →

Some of the most vexing problems I have dealt with in my career are related to connector corrosion problems. While corrosion can create a hard failure (easy to find), more often it creates an intermittent failure (hard to find). Intermittent failures can be very expensive to find. For example, the automotive industry spent years dealing with intermittent connector problems that were caused by fretting. Continue reading →