Substitution of Obsolete
Polycarbonate (PC) Capacitors
After the
discontinuation of Polycarbonate film (end of 2000) as a
capacitor dielectric by the only manufacturer, Bayer
AG/Germany, we have removed all MKC ranges (metallized
capacitors) and
FKC ranges (film and foil construction) using this capacitor film from
our range of products latest after inventory of film has
run out.
However, the question of which capacitors can be used to
replace the PC series is still of interest. The following
comparisons may be of assistance in making decisions.
The special
feature of Polycarbonate (PC) capacitors is the almost
constant course of capacitance drift versus temperature and the suitability for special applications in
the field of higher frequencies respectively.
Capacitance
change with temperature
Dissipation
factor with frequency
Substitution by Polyester
(PET) Capacitors
Results: In the field of normal application
temperature 0/+20 to +80°C Polyester (PET) shows
a comparable linearity of the capacitance course
in the positive field in comparison with
Polycarbonate (PC) which shows a slightly
negative course. The capacitance inconstancy
versus time is basically identical with both
dielectrics.
Capacitance
change with temperature
Substitution
suggestions for metallized capacitors:
Obsolete WIMA
type
PCM
Suggested WIMA
type
PCM
Replace also
obsolete competitor series
WIMA MKC
02
2.5
WIMA MKS
02
2.5
WIMA MKC
2
5
WIMA MKS
2
5
MKC 1858 / CMK
WIMA MKC
3
7.5
WIMA MKS
4
7.5
CMK
WIMA MKC
4
>10
WIMA MKS
4
>10
MKC 1862 / MKC
344 / CMK
Substitution
suggestions for film/foil capacitors:
Obsolete WIMA
type
PCM
Suggested WIMA
type
PCM
Replace also
obsolete competitor series
WIMA FKC
02
2.5
WIMA FKS
02
2.5
WIMA FKC
2
5
WIMA FKS
2
5
KC 1850 / CFR
(CMK)
WIMA FKC
3
>7.5
WIMA FKS
3
>7.5
CMK
Note: size comparisons
between series are possible for the most parts.
Substitution by
Polypropylene (PP) Capacitors
Capacitance
change with temperature
Dissipation
factor with frequency
Results: in comparison to
Polycarbonate (PC), Polypropylene (PP) has a lower
dissipation factor throughout the course of the whole
temperature field.
Substitution
suggestions for metallized capacitors:
Obsolete WIMA
type
PCM
Suggested WIMA
type
PCM
Replace also
obsolete competitor series
WIMA MKC
2
5
WIMA MKP
2
5
MKC 1858 / CMK
WIMA MKC
3
7.5
WIMA MKP
4
7.5
CMK
WIMA MKC
4
>10
WIMA MKP
4
>10
MKC 1862 / MKC
344 / CMK
WIMA MKC
10
>7.5
WIMA MKP
10
>7.5
Substitution
suggestions for film/foil capacitors:
Obsolete WIMA
type
PCM
Suggested WIMA
type
PCM
Replace also
obsolete competitor series
WIMA FKC
02
2.5
WIMA FKP
02
2.5
WIMA FKC
2
5
WIMA FKP
2
5
KC 1850 / CFR
(CMK)
WIMA FKC
3
>7.5
WIMA FKP
3
>7.5
CMK
Note: size comparisons
between series are possible for the most parts.
Substitution by Capacitors
with Mixed Dielectric (Recommended)
Capacitance
change with temperature
(f = 1 kHz) (general data)
-Mixed dielectric -Polycarbonate film
Mixed film capacitors
introduced by WIMA some years ago based on a combined
dielectric made of PET and PP capacitor films with properties
which come very close to those of PC as regards
capacitance and HF behaviour. The special feature of
these mixed dielectric capacitors is the almost constant
course of capacitance drift versus temperature.
Substitution
suggestions for metallized capacitors:
Obsolete WIMA
type
PCM
Suggested WIMA
type
PCM
Replace also
obsolete competitor series
WIMA MKC
2
5
5
MKC 1858 / CMK
WIMA MKC
3
7.5
7.5
CMK
WIMA MKC
4
>10
>10
MKC 1862 / MKC
344 / CMK
Substitution
suggestions for film/foil capacitors:
Substitution by Polyester
(PET) Capacitors
