ipedia.org/wiki/Railway_electrification_in_Great_Britain
Cortland Richmond
On 7/4/2012 1228, Scott Xe wrote:
Hi Andy,
Is there any particular reasons to have 110 Vac for railway signalling
system in a 230/240 Vac country?
Scott
-
This message i
;s no need to test real-time clocks at their fundamental frequency.
Cortland Richmond
On 7/5/2012 1112, Mcburney, Ian wrote:
Dear Colleagues;
I am trying to establish the maximum measurement frequency for
radiated emissions for a digital device that is an unintentional
radiator (part 15).
.0 30
__
f = frequency in MHz *Plane-wave equivalent power density
Cortland Richmond /
/
On 7/7/2012 1215, Macy wrote:
[Fourth attempt to get MY mail server to post to the group, so a lot of
information has been removed.]
I would say that they refer to the INSTANTANEOUS bandwidth. Cortland Richmond-Original Message-
From: "Airy, Chad"
Sent: Aug 6, 2012 6:43 PM
To: "emc-p...@ieee.org"
Subject: MIL STD 461E NECESSARY BANDWIDTH
Greetings,Greetings to all, this is my first
http://www.cpsc.gov/ABOUT/Cpsia/sect218.html
and also
http://www.cpsc.gov/businfo/intl/market_en.pdf
Cortland Richmond
On 8/19/2012 1602, Brian Oconnell wrote:
Significance of CE mark to EU customs/surveillance is obvious and not point
(other than my head). Need to understand why there are
.
Cortland Richmond
On 8/20/2012 0842, Charlie Blackham wrote:
David
Look at European Frequency Allocations in CEPT ERC report 25,
http://www.erodocdb.dk/docs/doc98/official/pdf/ERCRep025.pdf.
433 MHz is allocated as an Amateur Radio Band, EN 301 783.
Regards
Charlie
*From:*itl-emc user group
o get
the correct peak. The broadband FS meter was not happy with that, but we
were able to verify the peak in real time, though most of the techs
didnt know what we were doing (another thread, maybe).
They didn't even WORK for me.
Cortland Richmond
On 8/20/2012 2003, Ed Price wrote
Hi, Brent,
From the work I did in the NW I'd say they need to add 16 2/3 Hz to it;
the papers on AED susceptibility to railway power fields were a little
scary -- for folks in train stations, anyway.
Cheers,
Cortland Richmond
On 8/21/2012 0003, Brent G DeWitt wrote:
Re: [PSES] 6100
"Smart" batteries are electronic subassemblies that don't work properly
outside of the equipment in which they are meant to be used and must be
tested in it.
Cortland Richmond
On 8/22/2012 1243, rehel...@mmm.com wrote:
Can someone tell me if there are any EMC standards fo
iators equivalent
to the end use and receptors that will deliver equivalent RF to the
device under test. There's room here for some enterprising and
cash-flush (heh) lab to produce a White Paper.
VERY interesting discussion.
Cortland Richmond
On 8/23/2012 1234, Ken Javor wrote:
Re: &q
tests need to closely
approximate the actual use environment, which a passive charge
discharge/recharge cycle doesn't do for actively communicating smart
batteries.
Cheers,
Cortland Richmond
KA5S
On 8/24/2012 1313, Ed Price wrote:
Re: "Smart" Batteries
*Cortland:*
**
*I d
Can be done, has been done. We've used analog cancellation for a century
or so in telephones, after all. Op-Amps made it a lot easier to get 20
dB of it. And still no RF.
You may have been thinking of DSP noise subtraction, which does require
A/D, DSP and D/A circuitry.
Cortland
KA5S
On 8/2
your friend. Is such a requirement really needed? Folks
like us get paid for solving problems like that.
Cortland Richmond
ka5s
On 9/23/2012 1129, doug...@gmail.com wrote:
Aside from all the regulatory issues of leakage current and nasty failure modes
of MOVs. What methods have been used to d
,
domestically and in China. Got one memorable call in the middle of
*his* night from a VERY p*ssed off Chinese plant manager. Heh.
Old times. Who audits now?
Cortland Richmond
(ka5s)
On 10/16/2012 1503, John Woodgate wrote:
In message
,
dated Tue, 16 Oct 2012, ravinder.ajm...@hgst.com writes
I've noticed that when people don't understand a test, they often try to make it conform to every detail in the standards, prescripitve or or not. If it really mattered, I suppose one could turn the clamp sideways...Cortland Richmond-Original Message-
From: "Kunde, Brian
, how it is laid out should make no difference. See Fig. CE106-1 etc.
Also note that these tests are *relative* measurements so absolute
amplitude doesn't matter..
Cortland Richmond
On 11/30/2012 1959, Airy, Chad wrote:
The RE103 discussion under Test Procedures in Appendix *A.5.18
Chad,
hat should read "absolute amplitude ACCURACY does not matter".
Cortland
-
This message is from the IEEE Product Safety Engineering Society emc-pstc discussion
list. To post a message to the list, send your e-mail to
All
I had to take a closer look at your question and at the standard.
You don't have to worry about the bench, chamber, cabling and LISN's
(see Figure 2) when you bring a transmitter into the chamber for CE106.
The exemption also means you don't have to take a transmitter out of an
armored vehicle
n death in either a Glen Dash column, or an
EMC Club Banana Skins; I forget which.
** www.ncbi.nlm.nih.gov/pubmed/15294405
Might we have a psychologist speak at an EMC Symposium on "How to talk
your boss into doing the right thing"?
Cortland Richmond
On 12/7/2012 0232, John
rewired things so one didn't risk electrocution every them he did that
test. It must have been good enough, because various witnessed tests were
accepted.
This raises the question, however, of whether such a test was done on these
computers; it's pretty simple, or can be.
Cortlan
Files/HeartAntenna.pdf
Cortland Richmond
KA5S
On 12/15/2012 1246, Ken Wyatt wrote:
Hi All,
I just posted a couple articles that may be of interest.
1. Review: Com-Power PAP-501 broadband preamp
<http://www.tmworld.com/electronics-blogs/the-emc-blog/4403427/Review--Com-Power-PAP-501-broadband-preamp&g
s probably an FCC Commissioner now.
Cortland Richmond
On 3/1/2013 0853, Ron Pickard RPQ wrote:
Hi Bill,
The $2 bill is, in fact, still a current denomination of US currency,
albeit rarely used. It's introduction was back in the mid-1800s, I
believe. I still have a few of them from many
You need a constant-current source; how about an adjustable 3 terminal
regulator set up as one?
Cortland Richmond
On 3/1/2013 0900, Rene Charton/Twn/TUV wrote:
...ideas to generate a clean DC current?
-
This message is from
icane or a very intense
mid-latitude cyclone//
//950 mb (28.06 inches of mercury): CAT 3 Hurricane//
//870 mb (25.70 inches of mercury): Lowest Ever Recorded (not including
tornadoes)//
/http://www.theweatherprediction.com/habyhints2/410/*
*Cortlan
e tip,
I could produce enough ions to charge unsuspecting management
"trespassing" on our lab's linoleum floor enough to shock themselves
when they touched a metal door on the way out.
Heh!
Cortland Richmond
ka5s
On 3/8/2013 1029, Ken Wyatt wrote:
Yes, and the ESD standard was w
being examples.
I think a Test Report should and must say only what applicable laws,
standards and regulations require -- but all of that.
Cortland Richmond
On 3/13/2013 1148, Scott Xe wrote:
Critical component in EMC report
It is common not to have critical component list in EMC re
egal and that 2) it is possible to selectively jam only those
cellphones not located in staff spaces. I suspect also that he might
have a better case if he had asked why they didn't block all but
authorized NUMBERS.
Cortland Richmond
On 3/14/2013 0757, Pat Lawler wrote:
Cellphone sniffe
accept an Isaeli product or service
if they do not want to accept it.
Cortland Richmond
On 3/15/2013 1013, Ron Pickard RPQ wrote:
To all,
I've been asked by a colleague to verify what he has recently learned,
which is in Malaysia, a ruling by SIRIM does not recognize regulatory
certifi
Follow the links, Chris; this one looks promising:
http://www.bis.doc.gov/complianceandenforcement/index.htm
There is also a link for inquiries.
Cortland Richmond
On 3/15/2013 1154, Chris wrote:
Is Malaysia among the restricted countries on US list?
I remember some years ago that our
On 3/27/2013 1200, Steli Loznen wrote:
All my best wishes for a Happy Easter 2013.
Steli
chag sameach pesach!
Cortland
-
This message is from the IEEE Product Safety Engineering Society emc-pstc discussion
list. To post a me
On 3/27/2013 1856, N. Shani wrote:
Cortland et al,
Allow me re-organize the words slightly: chag pesach sameach (happy
passover holiday).
Naftali
Todah! I don't claim to SPEAK it; I do well to follow in a Siddur or
Haggadah. American, you know?
Cheers,
Cortland
-
---
escribe all the recognized labs
whose marks are acceptable.
I suspect a similar logic might then apply, were a non-EU cable
manufacturer to find his product denied entry for lack of the "HAR" mark.
Could be wrong: I am not a l
ality, and I found a
number of problems in the few years I was there.
Observation since has me suspecting that industry's current custom and
practice is to test as little as possible and wait for prosecutors to
discover problems.
Cortland Richmond
ka5s
On 7/11/2013 0534, Luke Turn
*Warning*
Contains peanuts.
I wonder if it is a violation of Prop 65 to knowingly report as present
_substances one has not even looked for_.
"They must be there; put up a sign!" makes notification meaningless.
Cortland Richmond
ka5s
On 7/11/2013 2255, Scott Douglas wrote:
When I
d have to read through it (again;
it's open on the table) to find where he talks about that. if you have
felt good about your work, you may already know what he is talking about.
Cortland Richmond
On 9/2/2013 0707, ce-test, qualified testing bv - Gert Gremmen wrote:
Well said.
We do agr
I'm not a power engineer, but I suspect you'll need something more than
pointed bus bars. A quick search comes up with this:
www.erico.com/public/library/fep/Surge/LT19915.pdf?
Good luck!
Cortland Richmond
On 9/6/2013 1156, Kunde, Brian wrote:
Our engineers are working on a
he builds, and just throwing in spark gaps, gas tubes,
Tranzorbs(tm) or MOV's might be asking for trouble. Know the threat, and
protect against THAT.
Cortland Richmond
On 9/9/2013 1130, Kunde, Brian wrote:
What are the safety considerations using gas tubes on the AC mains? Do
you ha
st work or have worked for firms who could
afford to buy copies of their own. But imagine one day finding that one
has been convicted in absentia of speeding through a town without speed
limit signs, limits available only by subscription.
Cortland Richmond
On 10/7/2013 1135, Peter Tarver wrot
Amund
I don't think of a green wire as RF "ground." What are Y caps DOING? They
are a return path for RF current that could otherwise get onto the mains
and cause interference. How does RF current get onto the power conductors?
Unbalanced switching noise? Yes, mostly. Capacitive coupling? Some.
Amund,
You do not HAVE to be in a chamber to keep working on this. Since there is
only one Vcc pin (which processor IS this? - be SURE there is only one Vcc
pin; you may have an unfiltered, unconnected Vcc pin or two) you are
limited in how many capacitors you can attach to it. This doesn't matt
it at all.
Cortland Richmond
---
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Technical Committee emc-pstc discussion list.
Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/
To cancel your subscription, send mail to:
m
oing schematic and layout reviews. THEN I
look for routing missteps and inadvertent loops. Others may prefer to
approach things in a different order; that's just my preference. But it
works for me.
Good luck!
Cortland Richmond
---
This message is fro
820pF is sufficient.
Regards,
Cortland Richmond
Amund Westin wrote:
>> Insert a SMD ceramic capacitor of value 820pF in parallel with the
existing
100nF. The reason for the low value 820pF is because the capacitor
self-resonance frequency is approximate 180MHz, and I believe it is
import
A loop can indeed radiate harmonics, if it is a reasonable fraction of a
wavelength long. A very small loop, tuned to
resonance by some capacitance, is less likely to do so.
Cortland
(The firm i work for, and my boss,
Don't know what I may write;
They don't stand by what I might say,
Which is p
Finally, a voice of sanity in news articles about
electromagnetic vulnerability. The ABC online news
headline is
High-Tech Robbery
Physicists Say
Electromagnetic-Aided
Robbery Limited to
Hollywood
htt
A small antenna with a 45 Mhz source and mixer at the center would retransmit a
US
cellphone on its own receive frequency. Would that do what you want?
Cortland - KA5S
(What I write here is mine alone.
My employer does not
Concur, agree or else endorse
These words, their mood, or thought.)
Ken
Actually, it's not the IEEE, but the IEE, a different organization.
Cortland
(If my firm wanted to say something, they wouldn't have ME say it! I don't
speak for them!)
---
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-p
>> If I assume that the top loaded antenna acts as a quarter wave stub,
that is it is extremely efficient at radiating all the power presented at
the base and not reflecting any back, and if I further assume this is CB
band or higher (essentially at or above 30 MHz), then 600 Watts 5 meters
away
Yeah, it is funny. or can be -- if you are not the guy being strip-searched
because my rig set off a metal detector!
I tell people I'm a Radio Interference Engineer. I can cure it - or cause
it.
In the US, the FCC limits permissible RF field strength only to protect
public health. The field str
Note to list members: Dave has seen my car. Dave, I shall have to come to Austin
and try it in your parking lot. (grin!) But don't look for me on a Segway!
That's too far to stand up.
Cortland - KA5S
(What I write here is mine alone.
My employer does not
Concur, agree or else endorse
These words
Never had to do that bulk current injection test (except some NEBS GR-1089
stuff). Is it with modulated RF, or merely
swept? Keying on and off can be much more severe in its effect than a
continuous carrier, or a gradual increase and
decrease with sweeping frequencies as cables resonate.
Cortla
In a closer-to-safety example, I've seen mobile radio affect screening devices
at a courthouse doorway
(I was parking for jury duty). Key down; lights up. Key up, works normally (40
meter band, about 10
meters away).
I've seen a poorly wired burglar alarm go off 30 meters from my car when I was
A worst case -- "real world" -- is probably just behind a radio equipped car,
mounting a capacitively top-loaded
antenna at its rear edge, and about 600 watts of RF.
With rather less power, 100 watts, I've occasionally seen adjacent cars'
engines stop when I transmit. It would be
interesting to
Remember the "Miss Piggy" driver? He wore a rubber mask so he could challenge
photo-radar citations. When I was there he had not lost a case, because
the photograph could not identify the driver, and there was at the time
no law requiring a driver to refrain from wearing a mask. I do believe
th
Back in the 1970's, I saw the electronic flash on a German radar activated
stoplight camera going off repeatedly during a snowstorm. No cars around,
of course, but I bet they got lots of snowflakes!
Cortland
(What I write here is mine alone.
My employer does not
Concur, agree or else endorse
Th
We need to separate specific regulation from general. The FCC does not care if
a radio front end is wide open, though
it now requires scanning receivers to have 38 dB image rejection. This does
not mean they have narrow front ends,
however. A SW receiver with a 75 MHz If may well have nothing
I don't believe this is what people are saying here. What they are saying
is, ordinary semiconductors won't demodulate RF levels produced by an unintentional
radiator.
Cortland
(What I write here is mine alone.
My employer does not
Concur, agree or else endorse
These words, their tone, or though
There is a difference between extending a warranty and being liable for
failure. If your seat belts fail some time
after the warranty is up, the manufacturer won't pay for fixing them on your
car. But the manufacturer may well be
held liable for the failure.
Cortland
"Andrews, Kurt" wrote:
AIrbag testing? Well, since it costs about $US 1500 to replace them (here), I
suppose there WOULD be a price hike!
One of the tests run on a modern, computerized auto when the ignition is
turned on is for airbag activation
circuitry.
Cortland
"James, Chris" wrote:
> I don't
I must disagree. The wording of Part 15 requiring users of Part 15 devices to
accept interference, does not reduce
complaints; hardly any users actually know it is there, or what it means. Fewer
care. If they are receiving one's
signals, they consider them intrusions to which they must react. T
"Some cars do this?" Nonsense! As you of course know.
1. It may be that your windshield antenna will not work with the particular
model radio you got, which would only mean drilling a small hole and
installing a whip. You should be able to find this out by calling the
manufacturer and asking.
I have it from a message on the r...@contesting.com list that Phillips bulbs
produce less RF noise than others.
I can't vouch for that, however.
Cortland
(What I write here is mine alone.
My employer does not
Concur, agree or else endorse
These words, their tone, or thought.)
Rich Nute wrote:
pensive to build or no one will be
able to sell them at a profit. They can't be
unreliable in the field or people won't buy them at
all. And they can't cause too many problems, or the
company will be sued. One factor weighs against
another.
We are at the balance point.
Regards,
Cortlan
I'm old enough, Ken, to remember ADF approaches! But
laptop switchers often operate inband to frequencies
used by aviation non-directional beacons. This makes
them more of a threat than the harmonics from
lower-frequency ones. It is also, of course,
possible for the laptop's other emissions to
int
If they meant "radio compass," that is a different can of monkeys.
The radio compass was traditionally the indicator for the ADF set , pointing
to the ground station, and was usually mounted so as to revolve in front
of a scale which rotated with the aircraft's' magnetic heading. A noisy
switch
It appears that a lot depends on what we mean by the
word "safety." If this means the elimination of
as-yet-unknown risks, why, nothing can be shown to
be safe. If we mean the prevention of hazards that
are reasonably predictable, we do that already. Or
should! The existence of standards which re
off a laptop due to interference with aircraft navigational or
communications systems. In one case, a specific frequency was reported.
Yet when the computer was checked, I could find no trace of an emission
anywhere near the frequency supposedly affected.
Cheers,
Cortland Richmond
(my opinion
Doesn't sound like you're missing anything. We are just talking about
different things. Common disease, here! Certainly, for the same directive
gain, the aperture of an antenna is smaller at higher frequencies. However,
I'm not holding gain constant, but size.
If the two antennas are the same p
An antenna of some physical size will indeed have gain increasing with
frequency. There is some justification, a 1 GHz antenna being reasonably
small, for assuming that antennas will have similar sizes -- and increasing
gain -- above 960 MHz. However, I suspect that the original limit was
simply a
The navigation systems which are protected by regulation were developments
of the 1940's, and -- except for interference! -- work pretty well. They
are analog technology, using phase and amplitudes of audio frequency tones
to determine position and/or deviation from course.
For landing, the ILS
I've been watching this discussion with interest. It appears you are
agreeing with each other - at some length. (grin) The subject of
interference to airborne navigation and communications receivers seems
never to go away. Since it was the probability of just such interference
which lead the FAA
Chris,
You SURE you want to do this? I believe CO's strictly isolate AC powered
gear. They have this "thing" about AC hum, you know...
Cortland
---
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
Vi
requencies more like a ground isolator. At RF, one MUST return current to
source in a short distance, which a typical CO ground system cannot
satisfy, or see radiated emissions and undesired coupling between units
increase.
Cheers,
Cortland Richmond
---
Th
One need only have a battery short in a pocket to receive a "heated"
reminder that batteries are not inherently safe devices. I've a pair of
trousers with a hole melted in them from an accidental short circuit.
Cortland
---
This message is from the IEEE
Why not turn off the lower voltage that RUNS the supply? You can also
ground the test sample when the door is open, using a contact separated
from ground during the test by a wedge able to withstand 10 kV.
Cortland
---
This message is from the IEEE EMC
If your product were audited, it would be tested as you sell it -- and if
that incorporated product D, it seems it would fail. As I understand
things, the entity which sells or places a product on the market is
responsible for its compliance; that would be you. So there's really
nothing for it but
Brian Kunde wrote:
>> Sometimes when we have a system tested for CE (emissions and immunity),
one of the other companies pieces of equipment will cause the "system" to
fail. <<
Yes, indeed. Luckily, I worked for a computer manufacturer and we could
find other vendors. Still, I have found it adv
A 4.7 uF capacitor is unlikely to have low enough series inductance to
prevent excessive noise on digital power and ground pins.
You have two needs. One is audio decoupling. For this, the big cap works.
The other is supplying digital switching currents. And for THAT, the big
cap fails. Your Vcc
Dave Heald wrote:
>> Does anyone know of any telecom (or general) reasons why thermal circuit
breakers may be unacceptable for telecom products? <<
Some thought on the matter suggests that thermal breakers may be too
variable in their trip current and time over the usual temperature range of
-4
Dave Palmer wrote:
>> Assuming that what I am actually taking about is dipole gain (I am a bit
of an ignoramus I'm afraid) Can anyone give me a basic approximate formula
for the variation of gain with frequency for frequencies that are up to a
factor of (say) 10 away (above and below) from the re
I've used the approach that one doesn't design compliance IN, one designs
non-compliance OUT. People who have the view that EMI reduction is a matter
of filters, shields and spring fingers, find out, if they don't know
already, that this is the expensive way to do things. They become more
recepti
When we started seeing 50 volt caps blowing up on a 5 volt output it became
evident that the problem _we_ had, "instant mortality" (grin), was
over-current, not over-voltage. We didn't actually see a voltage transient
- a 'scope had in fact ruled that out - but someone in management had
apparentl
Chris,
The issue isn't voltage rating; low-ESR caps such as these are susceptible
to excessive charging current at turn-on. At a former employer, we saw
REALLY GOOD, expensive caps used on a computer's 5V bus exploding at
turn-on, even ones rated at 50 volts. Replacing them with cheaper
electrol
>> So, what will happen to PLC (PowerLine Communication) in US ? I
>> know an application called CEBus and they operate in the frequency
>> band 100kHz-400kHz. Those folks using CEBus will not meet the new
>> conducted emission requirements.
>>
>> Maybe, that sort of equipment is not within the s
I don't have access to the documentation I did where I used to work (darn
it) but luckily, Jim Quarfoot at TI wrote a great article about ADSL
problems in the 25 July 2002 _Comms Design_. I recommend it.
( http://www.commsdesign.com/main/9812/9812feat1.htm )
Per the article, maximum ADSL power
Jim Eichner wrote:
>>A philosophical .vs practical question: Why is the FCC doing this? Is
it harmonization for the sake of harmonization, or are there real-life
issues
driving it? If it's the latter, what sorts of products have susceptibility
issues between 150kHz and 450kHz? <<
Don't forge
Derek Walton wrote:
>> I'm testing a product that's switching at 50 kHz, modulated by a 1 kHz
signal.
I'm getting a great deal of noise between 9 kHz to 13 kHz, I think is
related. Specifically, it goes when I stop the modulation... Any ideas on
ways to clean this up. Filtering seems to be e
I'd be interested in seeing what you've got. Remember, not only the board
can resonate, but structures on and in it, and at lower frequencies, too.
Don't send the file to my Compuserve address, though; I can only see text
here.
Cortland Richmond
k..
Some years ago, I had to show a TV-card vendor (their card made a compliant
computer fail Class B) the right way to do this. They were passing normal
video through, and had apparently never TESTED in standby mode to see what
interrupting shields with pigtails would do. I bundled all the video cab
Joe Martin (marti...@appliedbiosystems.com) asked:
>>Our company is planning on moving the Chemical Compliance Department from
the Quality Systems Department to the Compliance Engineering Department
(Product Safety/EMC). What do you see the advantages are in this
restructuring?<<
Depends if the
Phooey! How DARE you bring my musings down to the prosaic probabilities of
promiscuous spell checking?
Cortland
---
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
Visit our web site at: http://www.e
I swear this is true. From job requirements for a job, on monster.com:
·Ability to research and interrupt Bellcore, ANSI, IEEE, NEMA, and JIC
standards as applies to telecommunication and electrical equipment
required.
Cortland Richmond
---
This
Rick Busche wrote:
>>Speaking of surge and EFT I have been looking into
>>the real life performance of equipment installed
>>in the field. My equipment is three phase ITE and
>>is typically in operation in a "Heavy Industrial"
>>environment previously defined in EN 50082-2. In
>>particular this
As a victim of the older plug, I welcome such protection. At age 8, having
been told that I could be hurt by sticking my finger in the receptacle, I
of course had to try it, and am lucky to be alive.
Cortland
---
This message is from the IEEE EMC Society P
>> (the unplugging process may need to be repeated a few times until the
capacitor is disconnected when the mains is high at the time of
disconnection and so gets a "decent" charge!) <<
At a former employer, we monitored the wave form with a 'scope, and
repeatedly opened and closed the connectio
Chris,
I had a thought, reading your message, that even a plain metal sheet, if it
is close to a half wavelength across, has an RF hot spot in the middle. In
that case, you must keep one side of the sheet (plane) cold, while the
other is not. This means good grounds (UHF RF returns) at the edges.
List-Post: emc-pstc@listserv.ieee.org
Date: 20-Feb-02 13:38:27 MsgID: OUTBOX
MgTo: Gabi Hoffknecht >INTERNET:gab...@simex.ca
Subj: Re: Using PCB traces as transient voltage suppressor
Hi, Gabi,
I have a bad feeling about spark gaps on a board. There may be conductive
material left on the boa
When do you need a fuse? Level II is the only time you are allowed to lose
functionality, and the requirement for THAT is, it can't catch fire or
explode. I've seen "trace fuses" tried. The problem comes after the trace
blows. You are at the mercy of your board shop, and if you use a number of
th
Except... I (and other classic Compuserve users) won't see these messages
at all, unless and until they appear in someone else's REPLY in a form
Compuserve can send. It LOOKS great - but please don't send HTML to the
list.
Cortland
---
This message is fro
>> Your state that NEBS requires UL1950 safety testing. This may be true
for CPE but not equipment sitting at the CO. Please correct if I am
mistaken. <<
There's been a long wrangle but, yes, NEBS does now follow 60950. Some
accommodations appear to have been necessary, as it's evident that
clear
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