EMC Troubleshooting Kit – Part 2 (ESD Immunity)

This is a continuation of a description of my EMC troubleshooting kit as posted in the Test & Measurement “EMC Blog”. In the next few installments there, I’ll describe a few of the tools I use to test immunity of a prototype product to various stimuli. Bear in mind, immunity testing is a lot tougher to perform on the bench, so not all tests will be accommodated. To really ensure immunity levels, the product under test will have to be taken to a test lab.

So, what tests can be performed easily at the bench? These would include ESD, radiated immunity and certain pulse phenomenon. Of all the immunity tests, my experience has been that ESD and radiated immunity tests are the most likely to fail. In this installment, we’ll discuss one method to assess your circuitry or product against ESD phenomenon. There are several more ideas in The EMC Blog.

While you can’t beat an actual ESD simulator for pre-compliance testing, there are a number of simple ESD generators that will work well to at least give you a general feel for whether your circuitry is immune.

Here is a sample from the Test & Measurement “EMC Blog”:

One simple DIY ESD generator includes this BBQ grill igniter. You can purchase a replacement kit for a few dollars and the included wiring makes a good loop antenna. Holding this near your circuit board or close to the I/O and input ports to your product can indicate quickly if there are ESD issues. I’ve measured several volts into a simple UHF dipole antenna connected to an oscilloscope input. Edge speeds can be in the 50 to 200 ps range.

A simple piezoelectric BBQ starter is the heart of this ESD generator and can create large fields with 50 to 200 ps edges. The included wire makes a good loop antenna.