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Products » EPCOS AG Ferrites and Cores » ER Ferrite Cores »

ER Ferrite Cores

ER-configured ferrite cores are intended for construction of low profile small-size transformers and chokes for surface mounting or for multilayer windings based mounting on printed circuit board.

For cores of ER9,5/5, ER11/5 and ER14,5/6 configurations, boobins and mounting clamps for surface mounting are issued.

Find ER cores in our stock

Geometrical Dimensions

ER Ferrite Cores

Geometrical dimensions of ER-configured ferrite cores issued by Epcos AG.

Standard Size A




ER 9.5/5 9,5-0,3 5,0-0,2 5,0-0,2 3,2+0,3 7,5+0,25 3,5-0,2
ER 11/5 11,0-0,35 5,0-0,2 6,0-0,2 3,0+0,3 8,7+0,3 4,25-0,2
ER 14.5/6 14,5±0,2 5,9±0,1 6,7±0,1 3,3±0,2 11,8±0,2 4,7±0,1
ER 18/3/10 18,0±0,35 3,15±0,1 9,7±0,2 1,6±0,1 15,6±0,3 6,2±0,15
ER 23/5/13 23,2±0,45 5,1±0,1 12,5±0,25 3,1±0,1 20,2±0,4 8,0±0,2
I 23/2/13 23,2±0,45 2,1±0,1 12,5±0,25 0,2 max 20,2±0,4 8,0±0,2
ER 25/6/15 25,0±0,5 5,5±0,1 14,8±0,3 3,1±0,1 21,7±0,4 9,4±0,2
I 25/3/15 25,0±0,5 2,5±0,1 14,8±0,3 0,2 max 21,7±0,4 9,4±0,2
ER32/5/21 32,0±0,6 5,1±0,1 21,0±0,4 2,7±0,1 29,7±0,4 11,2±0,2

Information on bobbins and clamps that are issued by Epcos AG for standard sizes of ER9,5/5, ER11/5 и ER14,5/6 may be accessed by opening a corresponding pdf file from the table shown above.

Lepcos Co. recommends also to use with ER-configured ferrite cores made by Epcos AG additional nomenclature list of bobbins and clamps produced other firms.

Designation in Design Documentation

Example of EPCOS code explanation and designation in design documentation:

N87 ER11,5/5 A=160 nH ±3% B66325-J160-A87 — full name of ferrite core.
ER11,5/5 — configuration and standard size of core.
B66325 — ER11,5/5 standard size code.
160 — core is made with a gap corresponding with single-turn inductance coefficient AL=160 nH.
A — gap execution precision for AL (±3%).
87 — core is made of N87 ferrite brand.

Additional Information

To decrease losses on transportation and storage, it is recommended (as possible) to order cores and boobins in multiples of amounts contained in factory package. Information on number of cores in standard factory foam plastic package is given in here.

05.06 09 
Epcos has developed a new N95 power ferrite material with an exceptionally low power loss.

12.05 09 
New Epcos ferrite ring core sizes : N87 R20*12*6 and N87 R28*16*9

02.02 09 
New Epcos ferrite E core size : N87 E16/8/7,8 B66502GX187


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