FITs (failures/billion hours) for tantalum capacitors as documented in
Bellcore TR-332, Reliability Prediction Procedure for Electronic
Equipment (Issue 6, December 1997) are very low. For solid, hermetic
tantalum capacitors the FIT is 1.0 failure/billion hours (MTBF of
100,000,000 hours). For
David,
Even under normal conditions, Tantalum capacitors are
prone to failing, with the failure mode being a short-circuit.
At Sun, we use ceramic capacitors instead of Tantalum capacitors
where ever possible. In applications where high capacitance is
needed, (i.e. 47 uF and higher,) fused
Jack,
From you message it seems you are more interested in determining what
levels of RF conducted emissions appear at your radio DC terminals - that
way, if your emissions are below FCC 15 and EN55022 AC line conducted
standards, you can make the argument that your product will not adversely
Tantalums give you the advantage of a high Capacitance per unit volume. Their
reliability is proportional to the applied voltage versus rated voltage,
operating temperature versus rated temperature and power dissipation
(Vripple*2*pi*f*C)
The do most often fail in a short circuit. They should be
H,
If the cables were made buy a recognized cable vendor and had UL
recognition postage stamp on the box or individually tagged you
shouldn't have had a problem, especially if your drawings showed the
correct materials. Sometimes UL inspectors have to be guided into
following their own
The biggest drawback with tantalums is that their normal failure mode is
a short circuit. I once spent a lot of time over a period of several
months trying to get MTBF figures from manufacturers, but had no
success.
I finally decided to use tantalums in the design anyway, primarily
because of
Jack,
DC line conducted requirements exist for aircraft, MIL-STD, Bellcore, and
some ETSI specifications, and each standard specifies the test set-up and
equipment used.
From you message it seems you are not so much testing to one of these
specs, you are more interested in determining what
Ed,
In my simple minded way of looking at things in terms of units, Amp/Watt
= Amp/((Amp)(Volt)) = 1/Volt. Hence the quantity is neither
conductance, nor admittance.
Jim
---
Dr. Jim Knighten
NCR
Can anyone tell me if there are any drawbacks in using
tantalum capacitors in dc power supply filters? My recollection
is that they can pop if the voltage polarity is reversed, or if
there are large negative voltage swings during transients.
TIA,
David Brumbaugh
The BOEING Company
Eric,
I guess we need to know more information such as:
1) What Safety standard are you using?
2) What type of circuitry is this wiring connected to?
Generally, 300V wire is not considered to comply with the requirements for
reinforced insulation because it cannot be controlled at a minimum
Not sure...but maybe 600V wiring is required based on the primary protectors
which are rated at 600V.
Hope this helps,
Mel PedersenMidcom, Inc.
Homologations Engineer Phone: (605) 882-8535
mpeder...@midcom.anza.com Fax: (605) 886-6752
--
Quick civics lesson:
The 4th protects us from search and seizure without a warrant. I
think you mean the 5th, which says you can't be compelled to testify
against yourself.
__ Forward Header __
Subject: Re:
This is a test message please ignore
* opinions expressed here are personal and in no way reflect the position of VG
Scientific
We have some trouble about the classification according to CISPR 11 of a
diagnostic NMR device. In my opinion the radio frequency energy is NOT
genereted for treatment of material (human body). This condition applies
only to therapy equipment that produce some change in the body. For that
In my opinion, conducted emissions are ment for main operated equipment
only, and the measurements are to be taken on the mains only. If you market
a dc power source to power your dc to dc converter or you recommend such a
device, then your converter must be tested with that source. Otherwise, you
Check section 725 of the National Electrical Code. Class 1 (CL1) wire must
be rated 600V. But I don't think your application is Class 1. That is a high
power signal application. Your cable may be able to qualify as CL2 or CL3,
both of which do not require a conduit. If you must run the cable in a
Ed Price wrote:
snip
And what is an Amp per Watt? Is that a mho, a unit of conductance?
Or is it a unit of admittance, a Siemen?
hm... Wasn't mho one of the Three Stooges or am I thinking of something
else?!
No - I won't admit to anything - (no 4th over here)
(I'm sorry - it's Tuesday and for
Hi Group!
I need some help unravelling the calculations associated with the MIL-STD-462D
Method CS114 Loop Circuit Impedance Test.
Specifically, once you have a table of Forward Applied RF Power (in dBm) and
Observed Injected Current (in dBuA), how do you arrive at the Normalized Amps
per
--- On Mon, 29 Jun 1998 16:02:43 -0400 Schanker, Jack jschan...@mdsroc.com
wrote:
I wonder if anyone can help me with my confusion over the proper way to
evaluate conducted EMC on the DC input lines to DC-DC converters.
Uhhh, conducted EMC is kinda fuzzy thinking. Very low conducted
Like most compliance questions, there are a few different answers here,
and more questions.
1) Are the measurements being made for a converter, or for your radio?
2) If the product is a radio, it has to meet other requirements besides
EN55022 (e.g.- ETSI). In these cases, there are measurements
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