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From: Chuck Harris cfhar...@erols.com
Sender: time-nuts-boun...@febo.com
Date: Sun, 16 Jan 2011 17:43:18
To: Discussion of precise time and frequency measurementtime-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] GC-1000
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Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] GC-1000 Clock Cap Choice?
I have found that such high dielectric constant capacitors have other
problems in some circuits. While the capacitance value is dropping,
as much as 50
...@febo.com
Date: Sun, 16 Jan 2011 17:43:18
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] GC-1000 Clock Cap Choice?
I have found that such high
On 01/16/2011 11:15 PM, Poul-Henning Kamp wrote:
In message4d336a19.40...@freenet.de, Dr. Frank Stellmach writes:
High cap value Ceramics are available since years, [...]
Can you clarify one thing for me: When I studied datasheets for these
it looked like they drop 50% of their capacitance
Hi Magnus:
I've just placed an order for 16 different kinds of caps.
Most of them are either low leakage or low series resistance
electrolytic types but also a small number of plastic film caps. Should
be here in a few days.
Also have replacements for the tone decoder PLL ICs and the Op Amps
Brooke,
On 01/19/2011 09:31 PM, Brooke Clarke wrote:
Hi Magnus:
I've just placed an order for 16 different kinds of caps.
Most of them are either low leakage or low series resistance
electrolytic types but also a small number of plastic film caps. Should
be here in a few days.
It would be
Hi:
More than half the electrolytic caps in this Heathkit GC-1000 Most
Accurate Clock are bad and I'm trying to come up with modern replacements.
http://www.prc68.com/I/HeathkitGC1000.shtml#Rx
The Tone Decoder board uses a couple of NE567 PLL ICs to capture the 100
Hz and 1000 Hz WWV tones.
Also how about using Aluminum Organic Polymer caps (where there are
replacements) instead of the plain electrolytic caps?
One problem with using low ESR caps is that some regulators depend upon the
ESR for stability.
The plan is to replace all the electrolytic and tantalum caps since the
Hi Brooke,
Our electronics designers (@automotive electronics supplier) have to
take lot of care concerning voltage stabilizers, that the cap provides
sufficiently low ESR, which electrolytics deliver only at much higher
capacitance value; and a series resistor is introduced to limit loading
In message 4d336a19.40...@freenet.de, Dr. Frank Stellmach writes:
High cap value Ceramics are available since years, [...]
Can you clarify one thing for me: When I studied datasheets for these
it looked like they drop 50% of their capacitance at a DC voltage
of 10-20V.
Doesn't that make them a
I have found that such high dielectric constant capacitors have other
problems in some circuits. While the capacitance value is dropping,
as much as 50% when you apply voltage, their physical volume is
changing. They behave as piezoelectric transducers.
I have used them inappropriately, and
Can you clarify one thing for me: When I studied datasheets for these
it looked like they drop 50% of their capacitance at a DC voltage
of 10-20V.
Doesn't that make them a so-so bargain for power supply bulk capacitance ?
Poul-Henning,
Pls. check the spec for dielectric material.
X5R is
Hi
The other thing to watch out for is the temperature coefficient. Some of the
high K materials move a *lot* with modest changes in temperature. There are
indeed industry standards on what a given dielectric code should be. In some
cases there have ben liberties taken interpreting the codes.
In message a9103007-9686-4310-a9e5-aa8b193d1...@rtty.us, Bob Camp writes:
In a modestly warm box (say 60 C) the net effect between voltage
and temperature may be that you have 1/4 your original capacitance.
That was sort of my conclusion too, not exactly the first thing that
springs to mind
I have found that such high dielectric constant capacitors have other
problems in some circuits. While the capacitance value is dropping,
as much as 50% when you apply voltage, their physical volume is
changing. They behave as piezoelectric transducers.
I have used them inappropriately,
If you've ever worked on more than a very few Tektronix TM-500 series modules,
you are well aware of the favorite epoxy dipped tantalum capacitor failure
mode... very low resistance dead short... usually ending up in a charred
stinky black blob. Whatever manufacturer they chose... was the
Sorry, epcos sold ceramics business, and was itself swallowed by TDK.
If looking for X5R and X7R cer caps, visit vishay, kemet, taiyo yuden,
murata and others instead.
This special material specification is well hidden at the official
manufacturers specs.
Those are high grade ceramic
Brooke,
WTF ! Just replace them with the same type as was in there. That will give you
another 20 or so years and by then you will be dead and won't give a damn.
The only critical (for that time) component would be the TC loop capacitors
for
the 567 PLL's. They should be silver mica types
[mailto:time-nuts-boun...@febo.com] On
Behalf Of WB6BNQ
Sent: Sunday, January 16, 2011 7:41 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GC-1000 Clock Cap Choice?
Brooke,
WTF ! Just replace them with the same type as was in there. That will give
you
another 20
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