Filtering as an Afterthought by Astute

As the demands of modern technology continue to grow, the problems caused by Electromagnetic Interference (EMI) are not going away. All electrical and electronic equipment has the potential to cause or be vulnerable to EMI during normal operation, and it’s up to the design engineer to manage the risk.

However, all too often companies are choosing to rely on a method that can only be described as “Build, Test, Panic”.  In other words, any potential problems that will be caused by EMI are forgotten or ignored during the design cycle in the hope that they will be identified when the equipment is sent for testing.  Some EMI problems will only become apparent once testing has started, but the technologies that the engineers are relying to solve these problems bring challenges of their own.

Redesigning the PCB to incorporate filtering would seem to be the obvious choice, but the relatively low value of the capacitors required for filtering is offset by the costs associated with a major redesign and the resulting delays.  In the current climate of allocation, simply getting hold of the right capacitor is by no means a certainty.

Filtered connectors present another alternative, especially as they demand little in the way of a design change.  The manufacture of filtered connectors is no easy feat, however, and getting hold of them can be an exercise in patience as lead times can be very long.

As a real alternative, the solution being adopted by more and more designers is typified by the EESeal from Quell.  The circuitry to provide filtering is embedded within a rubber seal that fits over the pins, instantly converting any plug into a filtered connector. The seal is protected within the existing connector and is fitted in seconds.

The EESeal turns any connector into a filtered connector, proving that leaving filtering as an afterthought need not be a disaster if you choose the right technology.