Abstract The article discusses the differences between the electromagnetic pulses at lightning (LEMP) and at high altitude nuclear explosion (NEMP or HEMP). The article also shows that these differences do not allow to transfer LEMP experience on to NEMP. The author questions the effectiveness of grounding of electronic equipment as the main protection principle against … [Read more...]
To EMP or Not to EMP… Is That the Question?
So what are our thoughts on the threat of an electromagnetic pulse event (God forbid) causing some sort of catastrophic damage to our telecommunications, power, and whatever other kind of electronic infrastructure that might be out there? I know, I know…it depends who you talk to! Being in the EMC business, I’d like to believe that I understand the fundamental issue (danger) … [Read more...]
They’re Everywhere, They’re Everywhere – Part II
In part one of this post, I noted that there are three primary EMC coupling problems that are associated with the green wire safety ground: 1. The green wire conducted noise current modulates the signal and shows up as a differential voltage change across the load.2. The green wire forms a pick-up loop and acts like a magnetic field antenna.3. The green wire loop acts as a … [Read more...]
They’re Everywhere, They’re Everywhere – Part I
Read Part II here.I just finished rearranging my office. It all started with buying a new MS Windows 8 computer (that’s a story all on its own) followed closely by the failure of my printer to feed paper. So I bought a new printer, which is about two times bigger than my old one, and it wouldn’t fit in the previous location. So I moved my little flat screen TV into the old … [Read more...]
The Hybrid Ground System
We’ve already concluded that for low frequencies the Star or SPG ground works best and at the high frequencies, the so-called equipotential ground plane with a MPG system works best. No one grounding system is perfect. On top of that, most of the equipment these days operates at frequencies from DC to daylight, so the grounding design has to cover all frequencies … [Read more...]
The Equipotential Plane That Isn’t
The success of the multipoint ground (MPG) system requires having an extremely-very-low RF impedance grounding connection to an extremely-very-low RF impedance equipotential reference plane. It also helps if the conducting materials are homogeneous and the bad things are kept separate from the good ones. Does that sound easy? You’re right – it’s not! A couple of posts … [Read more...]
Grounding Conductor Limitations!
I briefly mentioned some of the elements of grounding in the last post. Technically, there are three types of grounding systems that work: (1) the single point (a.k.a. star) ground (SPG), which uses wires; (2) the multipoint ground (MPG), which requires a ground plane or mesh; and (3) the floating (no) point ground (FPG). All three utilize some variety of RF … [Read more...]
EMC Engineers Come Bearing Gifts
It’s the holiday season again, when we celebrate the serious things in life and have some fun too.When EMC engineers come bearing gifts...tis NOT the season to be jolly. Fa-la-la, le-la-la-laa. In fact, it’s time to be worried. For to the EMC engineer, GIFTS is an acronym for: Grounding, Isolation, Filtering, Transient suppression, and Shielding. Sometimes it takes … [Read more...]
