Electron Products Inc.
FIXED FILM CAPACITOR DIELECTRICS
Polyester
(Mylar) Film:
A good general purpose plastic dielectric with
relativity low cost and high volumetric efficiency. Still the most popular of
the capacitor dielectrics. Available in both Metallized Polyester Film and
Polyester Film & Foil designs.
Combination
Film:
Combination Polyester (Mylar) and
Polypropylene. Extremely low temperature coefficient in the 0° C to 85° C
temperature range. Volumetric efficiency similar to Polycarbonate. Available in both
Metallized and Foil designs.
KF
(Polymer) Film:
Extremely high volumetric efficiency with
about 4 times the "K Factor" of mylar, making it about 1/4 the
size. Higher DF and lower IR are its disadvantages along with cost.
Polycarbonate
Film:
Lower DF, higher IR, better temperature coefficient and better
stability than mylar with a slightly lower volumetric efficiency. Second most
popular Dielectric. Available in both Metallized Polycarbonate Film and
Polycarbonate Film & Foil designs. Polycarbonate capacitors have a 100%
voltage rating from -55° C to +125° C.
Kapton Film:
Electrical properties similar to Mylar with a
much higher operating temperature going up to 250° C. A higher cost than mylar
limits its use.
Polypropylene
Film:
Very good temperature coefficient high IR, and
low DF make it good for AC operation. Usable to 105° C without derating. Has
become increasingly popular for AC applications. Available in both Metallized
Polypropylene Film and Polypropylene film & Foil constructions.
Polysulfone
Film:
Electrical properties similar to polycarbonate
with a very good temperature coefficient and higher operating temperature. Very
limited availability in the last few years has limited its use. Available in
both Metallized Polysulfone Film and Polysulfone Film & Foil designs.
Polystyrene
Film:
Very good electrical properties and excellent
stability are its advantages. Its big disadvantage is its operation is limited
to below 85° C and it is available in Polystyrene Film & Foil construction
only.
SuperMetallized
Polypropylene Film:
A very high current design for very high
frequencies up to 1 Megahertz. The ultimate in high current capacitors. They
are used for input filtering, high frequency transformer DC blocking and output
filtering. They are dry-section non-polar metallized film dielectric with
special high current end terminations resulting in very low ESR values and very
high DV/DT ratings. Larger than SuperMetallized Polypulse. Also popular in
snubber applications.
SuperMetallized
Polypulse Film:
Developed by American Capacitor specifically
for switching power supply type applications. They are used for input
filtering, high frequency transformer DC blocking and output filtering. They
are dry-section non-polar metallized film dielectric with special high current
end terminations resulting in very low ESR values and very high DV/DT ratings.
They are significantly smaller than metallized polypropylene capacitors and
have a 100% voltage rating from -55° C to +125° C. Capacitance change over
temperature is 4 times better than with polypropylene.
Teflon
Film:
The best electrical properties of all the
Dielectrics. Extremely high IR, low DF and operation to 250° C. Available in
both Metallized Teflon Film and Teflon Film & Foil constructions.
Paper
Film:
Paper or Kraft Paper is the oldest of the film
capacitor dielectrics. It is available in both Metallized Paper and Paper &
Foil constructions. The paper must be impregnated with Epoxy, Wax, Oil, or
other suitable impregnate. It is still popular for high voltage and AC rated
capacitors operating at lower frequencies. Paper is also wound with plastic
dielectrics in combination dielectric capacitors.
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Electron
Products Inc.
5367
Phone:
(626) 960-2299 Fax: (626) 814-4434
http://www.ElectronProductsInc.com
Updated: February 24, 2009
Electron URL: http://www.ElectronProductsInc.Com
E-mail: Sales@ElectronProductsInc.Com
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Products Inc. All rights reserved.