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- November 27th 2020 -
Call: 1 (800) 377-3244
We Are Open Monday to Friday From 8 A.M.- 5 P.M., (Pacific Time)
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E Cores for Inductors, Chokes, Power Supplies

E'CORES Series

A kit includes 1 bobbin, 2 core halves: Material #77, Permeability 2000, AL values given in mh/1000 turns.
AL (nH/Square Turn or nH/N2) is the AL value.
L is inductance in nH (nanohenries)
N is the number of turns of a wire
Required turns (N) = square root of (desired 'L' /'AL'), √'L' /'AL', or 1000 turns='mH' /'AL', (square rooted)
CWS ByteMark Part Number is the part number to use to place purchase order. 1 inch = 25.4 mm
W is the width of the core
HT is the Height of the core
LH is the Length of the core
Power is the power handling capability of the core
Material is the Ferrite material designator.
• Technical Data and Specifications of ferrites, including E Cores
•Drawing of E-cores in .PDF
•Specifications and Data sheets of E Cores in .PDF
• For material properties

Low order fees are charged to total a minimum payment of $25.
Quantity marked in red is subject to availability and prior sales, or back order.
Orders are processed in 2 to 3 business days.
Please call for volume and price inquiries or email

Part Number : E-188-77 (for one single core half, layed flat)

E = E Cores, 0.188 = Approx. Width Dimension, 77 = Ferrite Material Type

  Part Number Power
Permeability Quantity
on hand
E188-77 10 1290 2000 9 $2.50
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E250-77 20 1520 2000 21 $2.75
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E375-77 70 2540 2000 2 $3.50
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E500-77 100 4090 2000 0 $4.25
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E625-77 22 5210 2000 2 $6.00
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Disclaimer: CWS Bytemark reserves the right at any time and from time to time to make changes to design, technical specification, or construction of any product listed on this website without notice. CWS Bytemark also reserves the right to discontinue or limit sale of any product or service available throughout this website on temporary or permanently basis without notice. CWS Bytemark highly recommend customers not to use its products offered on this website for inappropriate use and applications. Products should be tested for its suitability by prospective customers in all possible applications and conditions.

WARNING: This product can expose you to chemicals, which is [are] known to the State of California to cause cancer and birth defects or other reproductive harm.  For more information go to

Any Comments, Suggestions or Questions? Contact us! Email:
CWS 353 West Grove Ave. Orange, California 92865
Call us Toll Free: 1-800-679-3184 or 1 (800) 377-3244
Tel: (714) 279-9010, Fax: (714) 279-9482

Copyright (C)2008, CWS Bytemark
Updated 2013 Jan. Rev. V3.1