Epcos issues 29 names of standard size ferrite cores E with dimensions from E5 to E80/30/20. Most often used cores are made from basic power ferrite brands N27 (for transformers and chokes intended for operation in frequency band of up to 100 kHz) and N87 (up to 500 kHz).
The advantages of using the E configuration ferrite cores may be attributed to low cost of the core itself in combination with a wide choice of winding frames and also a low labor content cost for manufacturing wrapped products on their base due to a simplicity of performing a row winding using machines.
Find needed E-cores in our stock
Geometric Dimensions of E cores
| Standard Size | A [mm] | B [mm] | C [mm] | D [mm] | h1 [mm] | h2 [mm] |
| E 6,3 | 6,3-0,25 | 2,0-0,1 | min. 3,6 | 1,4-0,1 | 2,9-0,1 | 1,85+0,15 |
| E 13/7/4 | 12,6±0,4 | 3,7-0,3 | min. 8,9 | 3,7-0,3 | 6,5-0,2 | 4,5+0,3 |
| E 16/8/5 | 16,0±0,5 | 4,7-0,4 | min. 11,3 | 4,7-0,3 | 8,2-0,3 | 5,7+0,4 |
| E 16/8/4 (SH4*4) | 16,0±0,5-0,7 | 4,0-0,4 | 10,4+1,0 | 4-0,5 | 8±0,25 | 5,2+0,4 |
| E 16/8/7,8 (SH4*8) | 16,0±0,5 | 8,0-0,5 | 10,9±0,5 | 4-0,4 | 8+0,25 | 5,2+0,4 |
| E 20/10/6 | 20,4-0,8 | 5,9-0,4 | min. 14,1 | 5,9-0,3 | 10,1-0,3 | 7,0+0,3 |
| E 25/13/7 | 25,0±0,7 | 7,5-0,6 | min. 17,5 | 7,5-0,5 | 12,8-0,5 | 8,7+0,5 |
| E 30/15/7 | 30,0±0,6 | 7,3-0,5 | min. 19,5 | 7,2-0,5 | 15,2-0,4 | 9,7+0,6 |
| E 32/16/11 | 32,0±0,7 | 11,0-0,7 | 22,7+0,1 | 9,5-0,6 | 16,4-0,6 | 11,2+0,6 |
| E 34/14/9 | 34,6±0,7 | 9,7-0,8 | min. 25,1 | 9,65-0,55 | 14,65-0,75 | 9,5+0,5 |
| E 36/18/11 | 36,0±0,5 | 11,5-0,5 | min. 24,5 | 10,2-0,5 | 18,0-0,4 | 12,0+0,6 |
| E 40/16/12 | 40,6±0,6 | 12,5±0,25 | min. 28,6 | 12,5±0,25 | 16,5±0,2 | 10,5±0,3 |
| E 42/21/15 | 42,0±0,7 | 15,2-0,5 | min. 29,5 | 12,2-0,5 | 21,2-0,4 | 14,8+0,7 |
| E 42/21/20 | 42,0±0,7 | 20,0-0,8 | min. 29,5 | 12,2-0,5 | 21,2-0,4 | 14,8+0,7 |
| E 55/28/21 | 55,0±0,9 | 21,0-0,6 | min. 37,5 | 17,2-0,5 | 27,8-0,6 | 18,5+0,8 |
| E 55/28/25 | 55,0±0,9 | 25,0-0,6 | min. 37,5 | 17,2-0,5 | 27,8-0,6 | 18,5+0,8 |
| E 65/32/27 | 65,0±1,2 | 27,4-1,0 | min. 44,2 | 20,0-0,7 | 32,8-0,6 | 22,2+0,8 |
| E 70/33/32 | 70,5±1,0 | 32,0-0,8 | min. 48,0 | 22,0-0,7 | 33,2-0,5 | 21,9+0,7 |
| E 80/38/20 | 80,0±1,8 | 20,2-0,8 | min. 58,9 | 20,2-0,8 | 38,5-0,8 | 27,9+0,8 |
The information on a standard range of winding accessories that are issued by Epcos AG for E configuration ferrite cores may be accessed by opening an appropriate pdf file from the table given above.
The Lepcos Company also recommends a using together with E configuration ferrite cores produced by Epcos AG, additional range of products low cost bobbins of other producers. Such products were good acknowledged with regard to their quality and more than 10-year experience of their using by leading manufacturers of radio-electronic industry in Russia.
The Determination in a Technical Documentation
Example of EPCOS code explanation and designation in design documentation
Measurement unit — piece (half-piece)
E42/21/20 B66329GX187 — full name of ferrite core.
E42/21/20 — configuration and standard size of core.
B66329 — code of E42/21/20 standard size.
87 — core is made from N87 ferrite brand.
Additional Information
In practice, all standard size series of Ш-shape cores (used in Russia) have full range of analogues in terms of geometric dimensions of E configuration ferrite cores. It simplifies their replacement by prototypes issued by Epcos and made from modern materials, without changing any setup dimensions on board. Conformance table may be viewed in this page (in Russian).
To decrease losses on transportation and storage it is recommended (as possible) to order cores in multiples of factory packs. Information on cores number in standard factory foam package is given in this page (in Russian).
