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From: john larkin <jl@glen--canyon.com>
Newsgroups: sci.electronics.design
Subject: Re: EMC compliance question
Date: Sat, 12 Oct 2024 16:30:26 -0700
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On Sat, 12 Oct 2024 23:30:46 +0100, John R Walliker
<jrwalliker@gmail.com> wrote:

>On 12/10/2024 18:07, john larkin wrote:
>> On Sat, 12 Oct 2024 12:25:27 -0400, bitrex <user@example.net> wrote:
>> 
>>> On 10/12/2024 11:22 AM, john larkin wrote:
>>>
>>>> 48 is super common now. All our phones are PoE powered, which is
>>>> typically about 54 volts. Digikey sells warts up to 65.
>>>>
>>>> The phones are cool. I can take one to Hawaii and plug it in and it
>>>> works just like it does here.
>>>>
>>>> I imagine that europe has tens, maybe hundreds of millions of PoE
>>>> devices with the chinese version of the CE mark molded into the case.
>>>>
>>>> So if european manufacturers realy have to do all the CE certs and
>>>> testing, they have one more reason that they can't compete with
>>>> imports.
>>>>
>>>
>>> So as of 2019 it looks like the US rules are similar to the European
>>> "can't enforce" rules in that the manufacturer takes responsibility for
>>> everything and it's up to the mfgr how and what tests they perform to
>>> determine compliance:
>>>
>>> <https://www.electronicdesign.com/technologies/test-measurement/article/21209868/recent-developments-in-emc-legislation>
>>>
>>> This makes it sound like it's not too expensive to do some basic
>>> compliance tests on a small-volume product in house:
>>>
>>> <https://incompliancemag.com/emc-bench-notes-how-to-use-spectrum-analyzers-for-emc/>
>>>
>>> Need a 1 GHz-ish spectrum analyzer at least as the main tool which
>>> aren't exorbitantly expensive nowadays.
>> 
>> I can buy a spectrum analyzer and a surfboard antenna for under $1000,
>> and can take a product out in the country and do an open-field test
>> and crudely ballpark its EMI signature.
>> 
>> CE requires screen room testing and more quantitative measurement.
>> 
>> The reality today is that few products are honestly certified for EMI
>> or safety, and life goes on pretty well. If a product causes massive
>> EMI problems or hurts people, civil and criminal liabilities apply.
>
>My experience differs.  Every product that I have been involved
>with has been independently tested by Intertek or a test lab of
>similar status.
>  > It's impressive how few EMI problems there are in real life.
>> 
>Maybe that is because many products are actually tested and compliant.
>I can remember when audio equipment was very susceptible to
>interference from many sources.  Those days are mostly gone.
>I have come across exceptions of course.
>
>John

Most audio equipment is digital now.