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EI Bobbins

EI bobbins for laminated and ferrite EI cores in low frequency and switching transformers.

35 parts 7 plastics RoHS compliant
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What This Series Covers

EI bobbins for laminated and ferrite EI cores in low frequency and switching transformers. There are 35 published part numbers, and every one lists the plastic, the pin count and the pin geometry where the drawing states them.

If a geometry in this series is close but not exact, the tool room can modify pin counts, section splits and mounting features on a new tool rather than forcing a redesign around a stock part.

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Materials Used In This Series

Counted from the published data for these 35 parts.

PBT19 parts
PA666 parts
GFN4 parts
PET3 parts
PBT& PET1 parts
PBT & PET1 parts
Phenolic1 parts

How to choose between them

All Parts In This Series

EI 16X5.5 Bobbin, no Pins, 1 Section - CB MagneticsEI 16X5.5 Bobbin, no Pins, 1 SectionPA66EI 19 Bobbin, Horizontal, 4+4 Pins, 1 Section - CB MagneticsEI 19 Bobbin, Horizontal, 4+4 Pins, 1 Section4+4 pinsPBTEI 19X5 Bobbin, Horizontal, 2+2 Pins, 3 Sections - CB MagneticsEI 19X5 Bobbin, Horizontal, 2+2 Pins, 3 Sections2+2 pinsPBTEI 19X6.2 Bobbin, Horizontal, 2+2 Pins, 1 Section - CB MagneticsEI 19X6.2 Bobbin, Horizontal, 2+2 Pins, 1 Section2+2 pinsPBTEI 19X8 Bobbin, Horizontal, 2+2 Pins, 1 Section - CB MagneticsEI 19X8 Bobbin, Horizontal, 2+2 Pins, 1 Section2+2 pinsPBTEI 19X8.3 Bobbin, No Pins, 1 Section - CB MagneticsEI 19X8.3 Bobbin, No Pins, 1 SectionPA66EI 24X7.5 Bobbin, No Pins, 1 Section - CB MagneticsEI 24X7.5 Bobbin, No Pins, 1 SectionPA66EI 25X7 Bobbin, Vertical, 3+3 Pins, 2 Sections - CB MagneticsEI 25X7 Bobbin, Vertical, 3+3 Pins, 2 Sections3+3 pinsPA66EI 28X11 Bobbin, Horizontal, 3+4 Pins, 2 Sections - CB MagneticsEI 28X11 Bobbin, Horizontal, 3+4 Pins, 2 Sections3+4 pinsPETEI 28X11.5 Bobbin, Vertical, 3+3 Pins, 1 Section - CB MagneticsEI 28X11.5 Bobbin, Vertical, 3+3 Pins, 1 Section3+3 pinsPETEI 28X12 Bobbin, Horizontal, 3+4 Pins, 2 Sections - CB MagneticsEI 28X12 Bobbin, Horizontal, 3+4 Pins, 2 Sections3+4 pinsPBTEI 28X12 Bobbin, Horizontal, 5+4 Pins, 2 Sections - CB MagneticsEI 28X12 Bobbin, Horizontal, 5+4 Pins, 2 Sections5+4 pinsPBTEI 28X12 Bobbin, Molded in, Horizontal, 5+5 Pins, 2 Sections - CB MagneticsEI 28X12 Bobbin, Molded in, Horizontal, 5+5 Pins, 2 Sections5+5 pinsPBTEI 28X13.5 Bobbin, Molded in, Vertical, 3+2 Pins, 1 Section - CB MagneticsEI 28X13.5 Bobbin, Molded in, Vertical, 3+2 Pins, 1 Section3+2 pinsPBTEI 28X15.5 Bobbin, Molded in, Horizontal, 3+2 Pins, 2 Sections - CB MagneticsEI 28X15.5 Bobbin, Molded in, Horizontal, 3+2 Pins, 2 Sections3+2 pinsPBTEI 28X16 Bobbin, Horizontal, 5+5 Pins, 2 Sections - CB MagneticsEI 28X16 Bobbin, Horizontal, 5+5 Pins, 2 Sections5+5 pinsPBTEI 28X17 Bobbin, Molded in, Vertical, 3+2 Pins, 1 Section - CB MagneticsEI 28X17 Bobbin, Molded in, Vertical, 3+2 Pins, 1 Section3+2 pinsPBTEI 28X18 Bobbin, Molded in, Horizontal, 5+5 Pins, 2 Sections - CB MagneticsEI 28X18 Bobbin, Molded in, Horizontal, 5+5 Pins, 2 Sections5+5 pinsPBTEI 28X7 Bobbin, Horizontal, 4+4 Pins, 2 Sections - CB MagneticsEI 28X7 Bobbin, Horizontal, 4+4 Pins, 2 Sections4+4 pinsPBTEI 35X10 Bobbin, Horizontal, 3+3 Pins, 2 Sections - CB MagneticsEI 35X10 Bobbin, Horizontal, 3+3 Pins, 2 Sections3+3 pinsPA66EI 35X10 Bobbin, Horizontal, 5+4 Pins, 2 Sections - CB MagneticsEI 35X10 Bobbin, Horizontal, 5+4 Pins, 2 Sections5+4 pinsPETEI 35X10 Bobbin, Horizontal, 6+6 Pins, 1 Section - CB MagneticsEI 35X10 Bobbin, Horizontal, 6+6 Pins, 1 Section6+6 pinsPBTEI 35X10.5 Bobbin, Vertical, 3+3 Pins, 1 Section - CB MagneticsEI 35X10.5 Bobbin, Vertical, 3+3 Pins, 1 Section3+3 pinsGFNEI 35X11 Bobbin, Horizontal, 5+5 Pins, 2 Sections - CB MagneticsEI 35X11 Bobbin, Horizontal, 5+5 Pins, 2 Sections5+5 pinsPBTEI 35X11.5 Bobbin, Horizontal, 5+5 Pins, 2 Sections - CB MagneticsEI 35X11.5 Bobbin, Horizontal, 5+5 Pins, 2 Sections5+5 pinsPBTEI 35X12 Bobbin, Horizontal, 3+4 Pins, 2 Sections - CB MagneticsEI 35X12 Bobbin, Horizontal, 3+4 Pins, 2 Sections3+4 pinsPBTEI 35X13 Bobbin, Horizontal, 5+5 Pins, 2 Sections - CB MagneticsEI 35X13 Bobbin, Horizontal, 5+5 Pins, 2 Sections5+5 pinsGFNEI 35X14 Bobbin, Horizontal, 4+4 Pins, 2 Sections - CB MagneticsEI 35X14 Bobbin, Horizontal, 4+4 Pins, 2 Sections4+4 pinsPBTEI 35X14 Bobbin, Molded in, Horizontal, 3+3 Pins, 2 Sections - CB MagneticsEI 35X14 Bobbin, Molded in, Horizontal, 3+3 Pins, 2 Sections3+3 pinsPBTEI 35X8 Bobbin, Horizontal, 4+4 Pins, 2 Sections - CB MagneticsEI 35X8 Bobbin, Horizontal, 4+4 Pins, 2 Sections4+4 pinsPBT& PETEI 35×7 Bobbin, Horizontal, 4+4 Pins, 2 Sections - CB MagneticsEI 35×7 Bobbin, Horizontal, 4+4 Pins, 2 Sections4+4 pinsPA66EI 41X13 Bobbin, Horizontal, 5+6 Pins, 2 Sections - CB MagneticsEI 41X13 Bobbin, Horizontal, 5+6 Pins, 2 Sections5+6 pinsGFNEI 41X13 Bobbin, Horizontal, 6+6 Pins, 1 Section - CB MagneticsEI 41X13 Bobbin, Horizontal, 6+6 Pins, 1 Section6+6 pinsPBT & PETEI14 Bobbin, Vertical, 3+3 Pins, 1 Section - CB MagneticsEI14 Bobbin, Vertical, 3+3 Pins, 1 Section3+3 pinsPhenolicEI57 Bobbin, Horizontal, 6+6 Pins, 1 Section - CB MagneticsEI57 Bobbin, Horizontal, 6+6 Pins, 1 Section6+6 pinsGFN

Selection Table

Every published part in this series with its geometry side by side.

Part numberMaterial
EI 16X5.5 Bobbin, no Pins, 1 SectionPA66
EI 19 Bobbin, Horizontal, 4+4 Pins, 1 SectionPBT
EI 19X5 Bobbin, Horizontal, 2+2 Pins, 3 SectionsPBT
EI 19X6.2 Bobbin, Horizontal, 2+2 Pins, 1 SectionPBT
EI 19X8 Bobbin, Horizontal, 2+2 Pins, 1 SectionPBT
EI 19X8.3 Bobbin, No Pins, 1 SectionPA66
EI 24X7.5 Bobbin, No Pins, 1 SectionPA66
EI 25X7 Bobbin, Vertical, 3+3 Pins, 2 SectionsPA66
EI 28X11 Bobbin, Horizontal, 3+4 Pins, 2 SectionsPET
EI 28X11.5 Bobbin, Vertical, 3+3 Pins, 1 SectionPET
EI 28X12 Bobbin, Horizontal, 3+4 Pins, 2 SectionsPBT
EI 28X12 Bobbin, Horizontal, 5+4 Pins, 2 SectionsPBT
EI 28X12 Bobbin, Molded in, Horizontal, 5+5 Pins, 2 SectionsPBT
EI 28X13.5 Bobbin, Molded in, Vertical, 3+2 Pins, 1 SectionPBT
EI 28X15.5 Bobbin, Molded in, Horizontal, 3+2 Pins, 2 SectionsPBT
EI 28X16 Bobbin, Horizontal, 5+5 Pins, 2 SectionsPBT
EI 28X17 Bobbin, Molded in, Vertical, 3+2 Pins, 1 SectionPBT
EI 28X18 Bobbin, Molded in, Horizontal, 5+5 Pins, 2 SectionsPBT
EI 28X7 Bobbin, Horizontal, 4+4 Pins, 2 SectionsPBT
EI 35X10 Bobbin, Horizontal, 3+3 Pins, 2 SectionsPA66
EI 35X10 Bobbin, Horizontal, 5+4 Pins, 2 SectionsPET
EI 35X10 Bobbin, Horizontal, 6+6 Pins, 1 SectionPBT
EI 35X10.5 Bobbin, Vertical, 3+3 Pins, 1 SectionGFN
EI 35X11 Bobbin, Horizontal, 5+5 Pins, 2 SectionsPBT
EI 35X11.5 Bobbin, Horizontal, 5+5 Pins, 2 SectionsPBT
EI 35X12 Bobbin, Horizontal, 3+4 Pins, 2 SectionsPBT
EI 35X13 Bobbin, Horizontal, 5+5 Pins, 2 SectionsGFN
EI 35X14 Bobbin, Horizontal, 4+4 Pins, 2 SectionsPBT
EI 35X14 Bobbin, Molded in, Horizontal, 3+3 Pins, 2 SectionsPBT
EI 35X8 Bobbin, Horizontal, 4+4 Pins, 2 SectionsPBT& PET
EI 35×7 Bobbin, Horizontal, 4+4 Pins, 2 SectionsPA66
EI 41X13 Bobbin, Horizontal, 5+6 Pins, 2 SectionsGFN
EI 41X13 Bobbin, Horizontal, 6+6 Pins, 1 SectionPBT & PET
EI14 Bobbin, Vertical, 3+3 Pins, 1 SectionPhenolic
EI57 Bobbin, Horizontal, 6+6 Pins, 1 SectionGFN

Questions About EI Bobbins

How many ei bobbins are published

35 part numbers, listed above with material and pin geometry.

What if my size is not in the list

Send the drawing. Tool design and injection moulding are in-house services, so a size that is not in the catalogue is quoted as a tooling job rather than turned away.

Which plastics are used in this series

PA66, PBT, PET, GFN, PBT& PET, PBT & PET.

Can you supply the matching core

Yes. Silicon steel amorphous and nanocrystalline cores are in the same catalogue and complete wound components can be quoted.

Do you provide drawings and CAD

Dimensioned drawings are sent as PDF on request. CAD files are released on request via WhatsApp or email rather than as an open download.

Send Your Part List

Catalogue parts are quoted from existing tooling. Anything outside the list is quoted from your drawing.

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