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Film Capacitors

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General Purpose
General Purpose EXTENDED
(2)
WCAP-FTBP Film CapacitorsWCAP-FTBE Film Capacitorsmore
EXT.
Interference Suppression
Interference Suppression EXTENDED
(4)
WCAP-FTX2 Film CapacitorsWCAP-FTXX Film CapacitorsWCAP-FTXH Film CapacitorsWCAP-FTY2 Film Capacitorsmore
DC-Link (MKP)
DC-Link (MKP)
(1)
WCAP-FTDB DC-Linkmore

Würth Elektronik capacitors

Big portfolio available ex stock

Würth Elektronik capacitors

Big portfolio available ex stock

Würth Elektronik has extended its capacitor portfolio. You will find an overview of our current technologies available ex stock in the graph. More details (e.g. series, characteristics, features, applications, etc.) about each product family can be found in the flyer or for example below. In our flyer you will also find information about our services.

Capacitor portfolio flyer
Relationship between voltage and capacitance in the diagram

Available series

  • Series WCAP-FTBP

    • Type: General Purpose
    • Boxed Type Metallized Polypropylene
    • Capacitance: 33 nF – 6.8 µF
    • Voltage:  160 – 630 V (DC)
    • Pitch: 7.5 – 27.5 mm
    View Product Series WCAP-FTBP

  • Series WCAP-FTBE

    • Type: General Purpose
    • Boxed Type Metallized Polyester
    • Capacitance: 10 nF – 6.8 µF
    • Voltage:  100 – 1000 V (DC)
    • Pitch: 7.5 – 37.5 mm
    View Product Series WCAP-FTBE

  • Series WCAP-FTX2

    • Type: X2-Capacitors
    • Safety Class: X2
    • Capacitance: 5.6 nF – 6.8 µF
    • Voltage:  275 V (AC)
    • Pitch: 7.5 – 37.5 mm
    View Product Series WCAP-FTX2

  • Series WCAP-FTXX

    • Type: X2-Capacitors
    • Safety Class: X2
    • Capacitance: 5.6 nF – 6.8 µF
    • Voltage:  310 V (AC)
    • Pitch: 7.5 – 37.5 mm
    View Product Series WCAP-FTXX

  • Series WCAP-FTXH

    • Type: X2-Capacitors THB
    • Safety Class: X2
    • Capacitance: 33 nF – 10 µF
    • Voltage:  310 V (AC)
    • Pitch: 15 – 37.5 mm
    View Product Series WCAP-FTXH

  • Series WCAP-FTDB

    • Type: DC Link
    • Capacitance: 1 – 75 µF
    • Voltage:  500 – 1200 V (DC)
    • Pitch: 27.5 – 52.5 mm
    View Product Series WCAP-FTDB

Characteristics

Characteristics

Film capacitors have a good current carrying capacity and are not dependent on voltage, such as MLCCs with DC bias behavior. The ESR value is low, which can be a significant factor in DC link applications compared to electrolytic capacitors, for example. In addition, film capacitors have a good longevity due to their self-healing properties.

Image of a table showing the technical specifications of a film capacitor. Listed are: capacitance 75 µF, voltage 1,200 V, ripple current 25.7 A, and maximum operating temperature 105 °C.

Inner structure

Inner structure

The picture shows the internal structure of our film capacitors using our WCAP-FTX2 (X2-Capacitors) series as an example. Film capacitors consist of a wound metalized plastic film. The pins are attached to this winding and then sealed in a plastic box using epoxy resin.

Image of a red film capacitor of type FTX2 with labeled components. The left side shows the outer view with labels for plastic box, contact layer, and pins. The right side shows a cross-sectional view with labels such as plastic box and self-extinguishing resin. At the bottom, the structure of a single-sided metallized polypropylene film is shown, including metallized and non-metallized areas.

Example applications

Audio amplifier (WCAP-FTBP)
AC mains filter (WCAP-FTXX/FTX2/FTXH)
Solar inverter (WCAP-FTDB)
LCD TV (WCAP-FTBE/FTBP)
Harsh environments (WCAP-FTXH)

Measurements

Redexpert

Measurements

Redexpert

With the help of REDEXPERT you will find the right capacitor based on your technical requirements. The tool supports, for example, with measured values for capacitance, impedance, ESR and dissipation factor (DF). The ability to compare individual components with each other in terms of measured values enables convenient component selection.

REDEXPERT
Computer screen with overlapping windows, graphs, and red 3D text: 'ONLINE PLATFORM BASED ON MEASURED VALUES.'

Webinar

Introduction to the capacitor technologies and how to use them

Webinar

Introduction to the capacitor technologies and how to use them

Capacitors make up two thirds of all electronic components and there is a huge diversity of technologies which can overwhelm young engineers. All capacitors store electrical energy in the electrical field created in a dielectric material and they are used for very diverse applications like voltage stability and filtering. How that works differs between tiny MLCCs and huge electrolytic cells, from pF ratings up to the hundreds of Farads in supercapacitors. In this presentation, we introduce different capacitor solutions taking into account the advantages and disadvantages and with a focus on the final application.

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Application notes and documents

  • ANP109: Impedance Spectra of Different Capacitor Technologies

    Impedance and capacitance spectra (or scattering parameters) are common representations of frequency dependent electrical properties of capacitors. The interpretation of such spectra provides a wide range of electrochemical, physical and technical relevant information. Those need to be separated from the ever-present measurement artifacts as well as parasitic effects.

    Read more (PDF)

  • All Capacitors are "Audio Capacitors"

    There is an ongoing discussion within the audio engineering community about the sound quality of amplifiers concerning the audibility of signal distortions. Apparently, capacitors used for coupling and decoupling signals are suspected to be the source or at least a contributor to high-frequency distortions that influence the hearing impression.

    Read more (PDF)

  • Capacitors for interference suppression

    Different capacitors are used for interference suppression, which have to fulfill certain properties. You will find in this PDF an overview about our different series and their use.

    Read more (PDF)

Video

  • Webinar “DC Link Capacitors: Specifications and Applications”

    In our webinar you will find more information regarding the specification and application of DC Link Capacitors. The following content is explained in more detail:

    • DC link capacitors in general
    • Applications of DC Link Capacitors
    • Comparison of Aluminum Electrolytic Capacitors and DC Link Film Capacitors using a concrete example
    • Interpretation of the datasheet values
    • Influences on the expected lifetime

    Do you have specific questions about your circuit? We are happy to advise you personally. Please contact your sales representative or write us via our chat.

    Learn more

  • Webinar "The Effects of Harsh Environmental Conditions on Film Capacitors"

    Humidity and temperature have always been critical for capacitors. Depending on the application, a wide variety of environmental conditions can occur. The location of use also determines the resulting humidity and temperature. An application in subtropical countries has a different demand on the components than the application in countries with more moderate climatic conditions. What can be done to meet such requirements?

    Learn more

FAQ filmcapacitors

Datasheet WCAP-CSRF

For most parts you can find the detailed information about packaging in the datasheet: If you cannot find them, please get in contact with Würth Elektronik. E.g. you can use the chat on the website.

Example: Page 3 of WCAP-CSRF component datasheet.

You can find the certifications in the datasheet, page 2.

In the case of X/Y safety capacitors, certification information can be found in PDF format in the online platform REDEXPERT.

These links are shown at the right end of the table, under the column “Certificates”.

We provide the document with all the values on our homepage.

You can also download the document by searching for “FIT” or “MTBF” in our download center.

This document reveals the FIT (Failures in time) and MTBF (Mean time between failures) values that can be calculated for each series based on the electrical stress (voltage applied in the case of capacitors) and the temperature applied according to calculation models of Telcordia SR-332 Issue 3.

Please refer to the table of contents at the beginning of the document to find the values for capacitors.

WCAP-FTX2, WCAP-FTXX And WCAP-FTXH are X2 interference suppression capacitors and have been specially manufactured and tested for use in the intended position between Line (L) and Neutral (N), as defined in the IEC 60384-14 standard. This is also called “across the mains”.

Some applications called capacitive power supply or transformerless capacitive dropper use X2 capacitors in the input line (between mains power and the load). This use is called “in series with the mains”.
For this application, special THB X2 capacitors with explicit confirmation of this application must be used. We confirm this for certain types by specifying “Across the mains or in series with the mains” under “Application” in the data sheet. Würth Elektronik offers X2 THB film capacitors under the series WCAP-FTXH.

WCAP-FTXX and WCAP-FTX2 film capacitors are to be used as X2 capacitors as defined in the standards, whereby their use in series with the mains is not permitted. This also applies to WCAP-FTXH components for which the data sheet only states “across the mains” under “Application”.

metallization foil capacitor chart

In contrast to other capacitor technologies (e.g. MLCC), metallized film capacitors have self-healing properties.

In metallized film capacitors, the dielectric is metallized with a thin layer.

The dielectric of the capacitors is only a few µm thick. In addition, polymers have amorphous structures that are not homogeneous. Furthermore, mechanical loads can lead to small defects in the dielectric. If a voltage is then applied that exceeds the dielectric's dielectric strength, the dielectric will break through.

The arc causes the thin metallization to evaporate.

As a result, there is no conductive material left locally, which means that the capacitor does not short-circuit under normal circumstances.

This phenomenon is described in the following image