What you mentioned about ESD is true. Much better to design for it than to try
and fix the design later. Unfortunately, the later approach is what is normally
done. ESD debugging should not be done in an ESD test area as the energy goes
everywhere and one has no control. My preferred method of
On Sat, 18 Feb 2023 19:12:57 +0900,
"T.Sato" wrote:
...
> However, in case of the EMC Directive, it requires "... it complies
> with this Directive when properly installed, maintained and used for
> its intended purpose."
>
> If if is considered that to install tens of LED lights in a house is
On Sat, 18 Feb 2023 11:07:01 -0800,
John Mcbain wrote:
> Absolutely, the requirement is "... it complies with this Directive when
> properly installed, maintained and used for its intended purpose." But
> what is "it"?
>
> I maintain that "it" is the product that is tested and sold, not all
Hi Tom -
Right - if the installer installs the product NOT according to directions,
then any interference is his problem. But if the installation is done
according to the manufacturer's instructions and causes interference, then
it is likely the manufacturer will bear some or all responsibility.
Hi Brent -
Yes, different testing certainly would be appropriate for different power
distribution and connection methods, so knowing ALL the details is very
important to decide how to test.
However, one *essential* piece of knowledge may be overlooked. What
exactly is the product being sold?
Back in a previous life when I worked on PCIe, VME, etc. boards that plugged
into a chassis, we would frequently start adding cards until we saw no increase
in emissions to satisfy compliance if a customer used multiples of our boards,
which was often the case. These were components however
I'm being a bit flippant, but;
- If I was in my 3rd-party test house role, it stops when the customer
says stop.
- If I am the steward of my company's product, it stops when my
"engineering judgement" says we've "done our best to find the worst".
Assuming, of course, that it's a DoC
Hi Tom -
Absolutely, the requirement is "... it complies with this Directive when
properly installed, maintained and used for its intended purpose." But
what is "it"?
I maintain that "it" is the product that is tested and sold, not all the
possible final configurations in which combinations of
An unanswered, and critical, question is:
Do the "daisy-chained" devices draw power produced by the initial item,
or do they all have independent power supplies?
- First case: Initial unit produces DC/AC for the additional units.
- Second case: the initial unit is a simple, passive "power
Dear Doug,
Very interesting! I am aware of humidity level that affects the insulation.
Thanks for your experiments that show the spark as well. If the humidity would
affect the leakage current, I do not notice the standard gives the humidity
condition for the current measurement. Is
On Fri, 17 Feb 2023 21:12:40 -0800,
John Mcbain wrote:
> The key is testing the . If all the light bulbs in your house and
> the connecting wiring was sold as a single product, then presumably it
> would have been tested for EMC in that configuration. I doubt that is what
> happened.
As I recall, this topic came up once before on this forum. But try as I
might, I'm unable to find any notes on it.
The idea, as I remember, was you test a single DUT, and then add another,
and another, until emissions do not increase appreciably or become
asymptotic with enough margin to the
Thanks, Aldo.
Separately, effects on inanimate objects like ESD materials and transmission
lines seem generally sensitive to relative humidity whereas humans, and likely
other mammals, are sensitive to absolute humidity measured as dew point
temperature. As temperature is not important up to
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