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Centralab (Central
Radio Laboratories, aka CRL) was a major manufacturer of capacitors in the early
days of radio and television, and pioneered many of the ceramic compounds that eventually
replaced paper and mica as dielectrics. In fact, according to this 2-page advertisement
in a 1951 issue of Radio & Television News magazine, their researchers
mixed and tested more than 20,000 ceramic compounds while developing a line of capacitors
that met strict precision, stability, and durability tests. It is reminiscent of
Thomas Edison reportedly having tried a thousand or more filament types for his
incandescent light bulb before arriving on a suitable candidate. Centralab did not
invent ceramic capacitors, but they played an important role in their adoption.
As with many of the early electronics companies, Centralab no longer exists. It
was bought by Philips Electronics Components in
1981
and later spun off as part of
BCcomponents
(Beyschlag Centralab components). Since 2002,
Vishay BCcomponents
has owned the Centralab name and intellectual property (IP).
Centralab Ceramic Capacitors
 Know "Why Ceramic Capacitors ... and You'll
Buy Ceramic Capacitors
Here are the facts about Ceramic Capacitors capacitors - why they are the most
permanent capacitors ... why they do a better job ... give a better performance
...
Choose the exact capacitors you need from the world's widest line of ceramic
capacitors - for jobs that demand the best in guaranteed TV-AM-FM servicing ...
Up until a few years ago, capacitor -design was based on one idea - "the bigger
the better." Paper and mica, etc., were cheap, readily available materials, and
their use was the only known art for making commercial capacitors (or "condensers"
as they used to be called).
Now don't misunderstand us ... those old condensers were really OK as far as
they went. But today there's something more to talk about ... Ceramic Capacitors.
Actually, the idea of ceramic capacitors isn't new. They've been used as electronic
components for more than 20 years. We call them new because it's only in the last
few years that service-engineers have paid any attention to them ... and because
some of these modern ceramic capacitors really are new ... with new higher voltages,
new and better physical characteristics. So if ceramic capacitors were overlooked
by service-engineers during the last few years ... we feel it's because you didn't
know about just how good they really are - or because what you needed wasn't available.
Let's take a look at modern ceramic capacitors and the story behind them. It
was in the early 1900's when German scientists discovered the dielectric properties
of ceramic materials. In the U.S.A., we had an abundant supply of mica and other
materials, so U.S. research men never bothered with ceramics. Then came World War
I, and ceramics became mighty important in European radio manufacture. Ceramics
were a long way from perfected but they did the job ... and continual improvement
made them increasingly important in the electronic field. Meanwhile, at Centralab,
we had started to investigate these new materials. It was soon found that U.S.A.
had a bigger source of raw ceramic materials and that our stocks were of vastly
superior physical and electrical characteristics.
Then one of our foreign representatives supplied us with a complete set of foreign-made
ceramic components. Result - Centralab developed a ceramic research program. The
program was big and thorough ... and it's still going on.
In a few years, Centralab put on the market its first ceramic capacitors. With
World War II, came tremendous developments in electronics. Radio, radar and other
electronic equipment demanded the finest in component parts ... and ceramic capacitors
came into their own. In fact, independent research has shown that during World War
II, in some classes of military equipment, there was not a single known instance
of a failure of a ceramic capacitor!
Thus, through the lessons learned over a period of 20 years of intensive research
- Centralab Ceramic Capacitors have today become the best capacitor buy for safe
guaranteed servicing. For when you use CRL ceramic capacitors, you're using the
benefits of hundreds of thousands of man-hours of research - experiments with over
20,000 different ceramic compounds!
That's why any ceramic isn't the best ceramic for the job. Each of those 20,000
ceramic mixes had definite physical and electrical characteristics ... and when
we say that Centralab today uses only 250 of those 20,000 tested compounds, you
can be sure that those discarded did not perform to the exacting requirements of
sensitive electronic circuits.
Yes, and if you compare the old-style paper and mica capacitors with modern ceramic
capacitors ... point for point, based on your own technical experience, you'll see
why ceramics are vastly better ... the safe, dependable way to assure a good service
job.
For example, every serviceman is aware of the moisture absorbing quality of paper
condensers ... and how moisture can seep in along the leads on mica units. Compare
these old designs with modern ceramic tubular and disc types ... Centralab's Ceramic-X
capacitor bodies are non hygroscopic ... moisture absorption being only 0.007% or
less! That fact alone means Centralab Capacitors give you and your service customer
the ultimate in reliability - even under severe tropically humid conditions.
Old-timers in the service field ... yes, and young ones, too, will recall the
bulky size ... the difficulty of handling old-fashioned large size capacitors ...
when size seemed to be an important factor in design. Now, look at modern ceramic
capacitors. They're less than 1/7 the size ... you can fit them anywhere!
When you look at this chart of the development of capacitors using various materials
... the tremendous improvement of the dielectric constant "K" with the entry of
ceramics into the field is dramatically evident.
One of the most serious problems with old-time capacitors was that they broke
down under high temperatures. Here again, ceramics have more than proven their superiority.
85° C. will not harm the modern ceramic capacitor. In fact, the ceramic body
itself can easily withstand any temperature encountered in electrical apparatus.
High capacity is well maintained under wide temperature variation. What's more,
the copper-silver electrodes are electro-bonded to the ceramic with a tensile strength
of 30,000 lbs. per square inch - thus preventing any possible change of the relative
position of the electrodes.
A typical example of the high degree of perfection and performance offered by
ceramic capacitors is contained in CRL Hi-Vo-Kaps. These units are rated at 10 -
20 and 30 KV and are intended exclusively for TV. You'll find that practically the
entire TV industry has standardized on these CRL units as original equipment for
this most exacting application.
When it comes to low power factors - check ceramics against all others. With
ceramics, initially it's 0.1% to 0.6%. After 100 hours at 95% humidity, it's 0.5%
to 3% and they'll return to normal! That's ceramic high efficiency! If it's accuracy
you want, ceramic capacitors can give you unusually close tolerances in wide range
of values.
In r.f. circuits, where drift is critical, one of the likely causes is temperature
change. Stabilization can be effected by capacitors which compensate for temperature
variations. Centralab pioneered ceramic capacitors for this purpose. This important
research resulted in Centralab's famous TC-Hi-Kaps Zero Temperature and Negative
Temperature Compensating units. These are a Centralab exclusive "First". For service-engineers
they are the industry's last word in accurate stabilizing capacitors.
Service-engineers today are called upon for more exacting work - -more downright
customer satisfaction. Every job that comes into your shop is a challenge to your
reputation. Regardless of the care in workmanship, no service job is better than
the components you put into it. To stay in business tomorrow - you can't take chances
today.
Field research shows that smart service-engineers everywhere are replacing all
old-fashioned or dangerously old capacitors with ceramic capacitors, within the
capacity ranges available. Particularly if there is any indication of possible failure
within a reasonably short period. For by-pass and coupling applications ... they're
using Centralab BC Hi-Kaps. For tuning applications, they're using temperature compensating
TC Hi-Kaps. It's their own assurance of a good job well done ... and their customer's
insurance of complete satisfaction. What's more, to the serviceman and customer
alike ... there's little or no premium in price.
* * *
You'll find Centralab ceramic capacitors are available in a wide variety of capacities
from any recognized better radio parts distributor. Ask him. And remember, Centralab
is the pioneer in the field of electronic ceramics. That fact alone is your best
assurance of engineering know-how, production know-how, and performance know-how
that permits no compromise with quality.
Ceramic Disc Hi-Kap Capacitors - provide very high capacity in extremely small
size, with minimum thickness. For by-pass, coupling and general applications. Superior
power factor and low inductance.
TC Temperature Compensating Ceramic Capacitors - stable units that do not change
in capacity under wide temperature variations - or may be selected to correct for
frequency drift in resonant circuits caused by temperature changes. Also superior
replacement for close tolerance micas.
Television High Voltage Capacitors - are the accepted standard for the TV industry.
Used for filter and by-pass in TV high voltage power supply and pulse filter for
cathode ray tubes. Ask for Centralab Hi-Vo-kaps.
Ceramic BC Tubular Hi-Kap Capacitors - for by-pass or coupling applications
and most general circuit work. Smallest size on the market. Remarkable stability
under high temperatures or humidity.
Capacitor Kits - several are available. Illustrated is assortment of 200 units
of most generally used values, supplied in a four-drawer metal cabinet, Often assures
required values will be on hand when needed in labs or for service. No charge for
cabinet.
Transmitting and High Accuracy Ceramic Capacitors - for applications involving
rigid frequency control. Used for holding oscillator frequencies to close limits.
Excellent as secondary Standards.
Yes, for the safest, quickest guaranteed servicing ... standardize on Centralab
Ceramic capacitors. You'll have the world's widest line to select from - as made
by Centralab, America's pioneer builder of ceramic capacitors. You can get complete
information on all the capacitors described here - plus other valuable service information
from Centralab's Catalog 27 ... available at your distributor's.
Centralab
Division of Globe-Union Inc.
910 E. Keefe Avenue • Milwaukee 1, Wis.
Posted September 8, 2020
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