Ta

pe

 W

oun

d Cores

48 Alloy

Orthonol

M

ag

ne

sil

Sup

erm

allo

y

 Pe

rm

allo

y 8

0

Bob

bin C

ores

TAPE WOUND CORES

48 Alloy

 

|

 

Orthonol

 

|

 

Magnesil

 

|

 

Permalloy 80

 

|

 

Supermalloy

WEBSITES

Visit Magnetics’ websites for a wealth of easy to access information on soft 
magnetic cores and materials…

All product specifications for Magnetics’ Ferrite Cores, Powder Cores and Tape 

Wound Cores can be found quickly by using the menu driven product locator.
Magnetics’ Digital Library contains all of the company’s technical bulletins, white 

papers and design manuals, which can be viewed on-screen or downloaded.

The Software section of the website provides access to the Magnetics’ software 

design aids for designing Common Mode Filters, Current Transformers, Inductors 

and MagAmps.

HEADQUARTERS

110 Delta Drive

Pittsburgh, PA 15238

USA

(p)

 1.800.245.3984 

1.412.696.1333    

magnetics@spang.com

www.mag-inc.com

MAGNETICS INTERNATIONAL

13/F 1-3 Chatham Road South

Tsim Sha Tsui

Kowloon, Hong Kong

(p)

 +852.3102.9337

    +86.139.1147.1417

asiasales@spang.com

www.mag-inc.com.cn

CONTENTS

1

HISTORY OF THE  
STRIP WOUND CORE

Magnetics Pioneered Strip Wound Cores.

Magnetics was established in 1949 when the commercial market for high 

permeability magnetic materials was virtually non-existent and development in this 

field was just taking root. The new simplicity and reliability with which magnetic 

components could be used opened many doors in the field of electronics. Magnetics 

was quickly positioned as a leader in this field and has remained so ever since.
The first tape cores were used in applications where they were superior to the 

fragile vacuum tubes. Tape wound core applications grew rapidly because these 

new magnetic components performed far better due to the inherent reliability and 

robustness of tape cores compared with vacuum tubes. They contained no parts to 

wear or burn out; and the effects of shock, vibration and temperature were small 

compared to other components. Tape cores also made it possible to build circuits that 

included electrical isolation or multiple-signal inputs whereas existing technologies at 

the time could not.
Today, Strip Wound Cores are used in magnetic amplifiers, reactors, regulators, static 

magnetic devices, current transformers, magnetometers, flux gates, oscillators, and 

inverters.  

ABOUT MAGNETICS

Magnetics offers the confidence of over fifty years 
of expertise in the research, design, manufacture 
and support of high-quality magnetic materials and 
components.

A major supplier of the highest performance materials in the industry including: 

AmoFlux

®

, XF

lux

®

, MPP, High Flux, Kool Mµ

®

, power Ferrites, high permeability 

Ferrites and Strip Wound Cores, Magnetics’ products set the standard for providing 

consistent and reliable electrical properties for a comprehensive range of core materials 

and geometries.  Magnetics cores are the best choice for a variety of applications 

including switched mode power supplies for telecommunications equipment, servers, 

and computers; Uninterruptible Power Supplies for datacenters; and inverters for 

renewable energy.
Magnetics backs its products with unsurpassed technical expertise and support.  

Magnetics’ Sales Engineers offer the experience necessary to assist the designer from 

the initial design phase through prototype approval.  Knowledgeable Sales Managers 

provide dedicated account management.  Skilled Customer Service Representatives 

are easily accessible to provide exceptional sales support.  In addition, Magnetics 

offers MyMagnetics, a self-service website, that provides 24-hour secure access to 

price, inventory availability, tracking, account information, and online purchasing.  

This support, combined with a global presence via a worldwide distribution network, 

including a Hong Kong distribution center, makes Magnetics a superior supplier to the 

international electronics industry.

History

History     .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 1

Materials & Applications

Materials & Applications    .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 2-3

Tape Wound Cores

Tape Wound Cores   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 4
Mag Amp Cores   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 4
Core Case Selection   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 5
Testing Parameters   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 6

Typical Hysteresis Loops

48 Alloy and Orthonol   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 7
Magnesil     .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 8
Square Permalloy 80 and Supermalloy   .  .  .  .  .  . 9

Core Loss vs . Induction Level

Core Loss vs . Induction Level   .  .  .  .  .  .  .  .  . 10-12

Notes

Intentionally Left Blank    .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 13

Tape Wound Core Sizes

Tape Wound Core Sizes   .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 14-15

Tape Core Design

Tape Core Design   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 16

Bobbin Cores

Bobbin Cores   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 17
Bobbin Core Sizes    .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 18-19
Bobbin Core Design   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 20
Bobbin Core Testing   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 21

Wire Table

Wire Table   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 22

Other Magnetics Products

Powder Cores & Ferrites   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 23
Custom Components & Prototyping   .  .  .  .  .  .  . 24
Warranty   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 24

Index

MATERIALS AND APPLICATIONS

SQUARE ORTHONOL  

(MATERIAL CODE A)

This material, a grain-oriented 50% nickel-iron alloy, is manufactured to meet exacting circuit 

requirements for very high squareness and high core gain, and is usually used in saturable 

reactors, high gain magnetic amplifiers, bistable switching devices, and power inverter-

converter applications. Other applications such as time delays, flux counters and transductors 

demanding extremely square hysteresis loops require selection of Square Orthonol.

SQUARE PERMALLOY 80 

(MATERIAL CODE D)

This material, a non-oriented 80% nickel-iron alloy, is manufactured to meet the high 

squareness and high core gain requirements of magnetic preamplifiers and modulators. It 

is especially useful in converters and inverters where high voltage at low power levels is 

required, but where circuit losses must be kept to a minimum. Square Permalloy 80 has a 

saturation flux density approximately one-half that of the Orthonol’s, but has coercive force 

values one-fifth to one-seventh that of the 50% oriented nickel-iron alloys.    

SUPERMALLOY 

(MATERIAL CODE F)

This material is a specially processed 80% nickel-iron alloy. It is manufactured to develop 

the ultimate in high initial permeability and low losses. Initial permeability ranges from 

40,000 to 100,000 while the coercive force is about one-third that of Square Permalloy 80. 

Supermalloy is very useful in ultra sensitive transformers, especially pulse transformers, and 

ultra sensitive magnetic amplifiers where low loss is mandatory.

48 ALLOY 

(MATERIAL CODE H)

This material, a 50% nickel-iron alloy, has a round B-H loop and exhibits lower saturation 

flux density, squareness, coercive force, and core gain than the Orthonol types. It is useful 

in devices requiring lower coercive force such as special transformers, saturable reactors, and 

proportioning magnetic amplifiers. AC core losses are lower than with Orthonol.

MAGNESIL  

(MATERIAL CODE K)

This material, a grain-oriented 3% silicon-iron alloy, is processed and annealed to develop high 

squareness and low core loss. It is usually used in high quality toroidal power transformers, 

current transformers and high power saturable reactors and magnetic amplifiers. It exhibits 

high saturation flux density with high squareness but has comparatively high coercive force 

and core loss. With its high Curie temperature, it is quite useful in magnetic devices which 

are to be exposed to temperatures between 200ºC (392ºF) and 500ºC (932ºF). At higher 

temperatures, only uncased cores should be used due to case temperature limitations. 

ROUND PERMALLOY 80 

(MATERIAL CODE R)

This material, a non-oriented 80% nickel-iron alloy, is processed to develop high initial 

permeability and low coercive force. It has lower squareness and core gain than the square 

type, as these characteristics are sacrificed to produce the high initial permeability and low 

coercive force properties. Round Permalloy 80 is especially useful in designing highly sensitive 

input and inter-stage transformers where signals are extremely low and DC currents are not 

present. It is also useful in current transformers where losses must be kept to a minimum 

and high accuracy is a necessity. The initial permeability of this material is usually between 

20,000 and 50,000.

MATERIALS AND APPLICATIONS

Magnetics offers soft magnetic core materials for saturating devices and high sensitivity magnetic circuits for all applications. These 

materials are especially selected and processed to meet exacting magnetic circuit requirements, and are manufactured to tight guaranteed 

tolerances according to IEEE test procedures or other common industry test methods.

2

MATERIALS AND APPLICATIONS

*  The values listed are typical of 0.002" thick materials of the types shown. For guaranteed characteristics on all thicknesses of alloys available, contact Magnetics Sales Engineering Department.

** 400 Hertz CCFR Coercive Force is defined as the H

1

 reset characteristic described by the Constant Current Flux Reset Test Method in IEEE Std. #393.

MATERIALS AND APPLICATIONS

mag-inc.com

3

Table 1

Table 2

PROPERTY

3% Si-Fe 

Alloys 

(K)

50% Ni-Fe 

Alloys 

(A, H)

80% Ni-Fe 

Alloys 

(R, D, F)

% Iron

97

50

17

% Nickel

….

50

79

% Silicon

3

….

….

% Molybdenum

….

….

4

Density (gms/cm

3

)

7.65

8.2

8.7

Melting Point (ºC)

1,475

1,425

1,425

Curie Temperature (ºC)

750

500

460

Specific Heat (Cal./ºCgm)

0.12

0.12

0.118

Resistivity (µ 

Ω

 -cm)

50

45

57

CTE (x10

-6

/ºC)

12

5.8

12.9

Rockwell Hardness

B-84

B-90

B-95

Material 

Code

 

Material

Flux Density

 

B

r

/B

m

Coercive Force

400 Hertz CCFR **

(kG)

(Teslas)

Oersteds

A/M

A

Square Orthonol

14.2 - 15.8

1.42 - 1.58

0.88 up

0.15 - 0.25

11.9 - 19.9

D

Square Permalloy 80

6.6 - 8.2

0.66 - 0.82

0.80 up

0.022 - 0.044

1.75 - 3.50

F

Supermalloy

6.5 - 8.2

0.65 - 0.82

0.40 - 0.70

0.004 - 0.015

0.32 - 1.19

H

48 Alloy

11.5 - 14.0

1.15 - 1.40

0.80 - 0.92

0.08 - 0.15

6.4 - 12.0

K

Magnesil

15.0 - 18.0

1.5 - 1.8

0.85 up

0.45 - 0.65

35.8 - 51.7

R

Round Permalloy 80

6.6 - 8.2

0.66 - 0.82

0.45 - 0.80

0.008 - 0.032

0.64 - 2.55

  

 

TYPICAL PROPERTIES OF  
MAGNETIC ALLOYS

MAGNETIC CHARACTERISTICS COMPARISON*

MATERIALS AND APPLICATIONS

Below is a quick reference for available combinations of materials, cases, and gauges.

*Cases/Coatings (Specifications on page 5)

50 series – cores in non-metallic cases (phenolic or nylon depending on availability)

51 series – cores in aluminum cases

52 series – cores in aluminum cases with epoxy coating

53 series – uncased/bare cores

54 series – encapsulated cores (red epoxy)

TAPE WOUND CORES

Material

Code

Material

Available  

Cases/Coatings*

Gauges (Thickness)

0.0005"

(Gauge Code 5)

0.001"

(Gauge Code 1)

0.002"

(Gauge Code 2)

0.004"

(Gauge Code 4)

A

Square Orthonol

50, 51, 52

X

X

X

X

D

Square Permalloy 80

50, 51, 52

X

X

X

X

F

Supermalloy

50, 51, 52

X

X

X

X

H

Alloy 48

50, 51, 52

X

X

X

X

K

Magnesil

50, 51, 52, 53, 54

X

X

R

Round Permalloy 80

50, 51, 52

X

X

X

  

HOW TO ORDER

Each core is coded by a part number that describes it in detail. A typical part number is:

01   5 1 0 2 9 2 A

Material Code

Gauge Code

Core Size

Case/Coating Code

01 - Single core or 02 - 03 - 04 matched sets

APPLICATIONS

Magnetics Tape Wound Cores are often key components of:

> Aerospace 

 

> Power Supplies

> Radar Installations 

> Current Transformers

> Jet Engine Controls

MAGNETICS Tape Wound Cores are made from high permeability magnetic strip alloys of nickel-iron (80

%

 or 50

%

 nickel), and silicon-iron. 

Tape Wound Cores are produced with ODs ranging from 0.438" to 3" in many sizes. 

Additional and custom box sizes are available.

4

Five sizes of cores have been designed specifically to be used as magnetic amplifier cores. 

Mag Amp cores have been designed to serve as a regulator in the control loop or the secondary 

outputs of the switch-mode power supply.
Magnetics website, www.mag-inc.com, provides a software program to assist the designer 

with Mag-Amp design. Using the values of output current, secondary voltage, frequency, duty 

cycle and head room, the program software will select the appropriate core and calculate the 

losses and temperature rise of the Mag Amp design.

MATERIALS AND APPLICATIONS

NON-METALLIC CASES  

(CASE/COATING CODE 50)

For superior electrical properties, improved wearing qualities, and high strength, non-metallic 

cases are widely used as protection for the core material against winding stresses and 

pressures. Both phenolic and nylon types meet a minimum voltage breakdown of 2000 

volts wire-to-wire. The glass-filled nylon types can withstand temperatures to 200ºC (392ºF) 

without softening, while the phenolic materials will withstand temperatures up to 125ºC 

(257ºF).

ALUMINUM CASES 

(CASE/COATING CODE 51)

Aluminum core cases have great structural strength. A glass epoxy insert, to which the 

aluminum case is mechanically bonded, forms an airtight seal. These core cases will withstand 

temperatures to 200ºC (392ºF), a critical factor in designing for extreme environmental 

conditions.

ALUMINUM CASE 
WITH GVB EPOXY PAINT 

(CASE/COATING CODE 52)

This case is the same basic construction as the aluminum box, but in addition it has a thin, 

epoxy-type, protective coating surrounding the case. This finish adds no more than 0.015" 

to the OD, subtracts no more than 0.015" from the ID, nor adds more than 0.020" to the 

height.
GVB epoxy paint finish offers a guaranteed minimum voltage breakdown of 2000 volts wire-

to-wire. This coating will withstand temperatures as high as 200ºC (392ºF) and as low as 

-65ºC (-85ºF) with an operating life of greater than 20,000 hours.

UNCASED/BARE CORES 

(CASE/COATING CODE 53)

Uncased cores offer a maximum window area. They also offer a slightly smaller package and 

lower cost where slight deterioration of properties after winding can be tolerated. 
Because of the extreme sensitivity of nickel-iron cores to winding stresses and pressures, such 

cores are not available in an uncased state. Magnesil cores are not as susceptible to these 

pressures and are available without cases. 

ENCAPSULATED (RED EPOXY) CORES 

(CASE/COATING CODE 54)

Encapsulated cores have a guaranteed minimum voltage breakdown of 1000 volts from core 

to winding. The temperature rating of this finish is 125ºC (257ºF).
Only Magnesil cores are available in encapsulated form. This protection is a tough, hard epoxy 

which adheres rigidly to the core, allowing the winder to wind directly over the core without 

prior taping. A smooth radius prevents wire insulation from damage.

CORE CASE SELECTION

5

8

TESTING PARAMETERS

6

TAPE CORE TESTING PARAMETERS  

SQUARE B-H LOOP TAPE CORES

Square loop materials include oriented silicon iron, Magnesil, oriented 50% nickel, Orthonol, and 80% nickel, Permalloy, with a square loop anneal. These cores are tested by the Constant-Current 

Flux-Reset test method as defined by IEEE Standard #393 which measures 4 points on the BH loop as shown in Figure 1.

B

max

 – The saturation flux density is the flux density swing from the origin of the BH loop to the saturation in one direction.

B

m

 - B

r

 is the difference between the maximum flux density (B

m

) and the residual flux density (B

r

). The lower this number, the lower the permeability in saturation and the lower the switching losses 

for a given core material.

B

r

/B

m

 – B

r

 residual flux density / B

m

, (squareness) is calculated.

H

1

 – The third parameter measured is the width of the hysteresis loop. The core is reset

  

1/3 

of the way down the loop from positive saturation to negative saturation. The loop width at this point is the 

H

1/3

 point, given in Oersteds. The narrower the B/H loop, the lower will be the corresponding core losses.

Delta H – The last parameter that this test measures is Delta H, or the additional amount of DC current or ampereturns required to set the core from BH

1/3

 down the loop to – BH

2/3

. H is read in 

Oersteds and cores normally have a maximum Delta H limit.

B   (Kilogauss)

+8

.08

.08

.04

.04

+4

+2

-2

-4

-6

-8

B

M

 - B

R

+B

M

-B

M

B

R

∆

H

H

1/3

H

2/3

B

R

H

(Oersteds)

Figure 1. Standard DC Reset Tester Measurements

MATERIALS AND APPLICATIONS

9

 

Typical Hysteresis Loops for 48 Alloy and Orthonol

(Kilogauss)

B (Tesla)

Orthonol

48 Alloy

(Oersteds)

H

+16

+12

+8

+4

-4

-8

-12

-16  

+1.6

+1.2

+.8

+.4

-.4

-.8

-1.2

-1.6  

-70

-60

-50

-40

-30

-20

-10

0

+10

+20

+30

+40

+50

+60

+70

+1.4

+1.0

+.6

-.6

-.4

-.2

+.2

H (A/m)

+.4

+.6

+.2

-.6

-.2

-1.0

-1.4

Typical Hysteresis Loops for 48 Alloy and Oronothol

B

7

TYPICAL HYSTERESIS LOOPS 

TYPICAL HYSTERESIS LOOPS

8

(Kilogauss)

B (Tesla)

Magnesil

(Oersteds)

H

+16

+20

+12

+8

-4

-8

-16  

-20  

+1.6

+2.0

+1.2

+.8

+.4

0

-.4

-.8

-1.2

-1.6  

-2.0  

-140

-120

-100

-80

-60

-40

-20

0

+20

+40

+60

+80

+100

+120

+140

-1.2

-1.6

-.8

-.4

+.4

H (A/m)

+.8

+1.2

+1.6

Typical Hysteresis Loops for Magnesil and Supermendur

B

+4

-12

Typical Hysteresis Loop for Magnesil

MATERIALS AND APPLICATIONS

TYPICAL HYSTERESIS LOOPS 

9

(Kilogauss)

B (Tesla)

Square Permalloy 80

Supermalloy

(Oersteds)

H

+8

+6

+4

-2

-4

-8  

+8

+6

+.4

+.2

-.2

-.4

-6

-8  

-14

-12

-10

-8

-6

-4

-2

0

+2

+4

+6

+8

+10

+12

+14

-.12

-.16

-.08

-.04

+.04

H (A/m)

+.08

+.12

+.16

Typical Hysteresis Loops for Sq Permalloy 80 & Supermalloy

B

+2

-6

Typical Hysteresis Loops for Square Permalloy 80 and Supermalloy

(Kilogauss)

B (Tesla)

Magnesil

(Oersteds)

H

+16

+20

+12

+8

-4

-8

-16  

-20  

+1.6

+2.0

+1.2

+.8

+.4

0

-.4

-.8

-1.2

-1.6  

-2.0  

-140

-120

-100

-80

-60

-40

-20

0

+20

+40

+60

+80

+100

+120

+140

-1.2

-1.6

-.8

-.4

+.4

H (A/m)

+.8

+1.2

+1.6

Typical Hysteresis Loops for Magnesil and Supermendur

B

+4

-12

CORE LOSS  vs. INDUCTION LEVEL

10

Core Loss (Watts/Pound)

Flux Density (Gauss)

10

8
6

4
3

2

.8
.6

.4

.3

.2

.08

.06

.04

.03

.02

100

1000

10K

20K

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

.1

1

.01

2 mil 48 Alloy (code = 2H)

10 KHz

6 KHz

3 KHz

 1 KHz

 400 Hz

Core Loss (Watts/Pound)

Flux Density (Gauss)

1000

100

1000

10K

20K

800
600

400
300

200

80
60

40

30

20

8

6

4

3

2

200

300

400

500

600

700 800 900

2000

3000

4000

5000

6000

7000 8000 9000

10

100

1

1 mil Square Orthonol (code = 1A)

100 KHz

50 KHz

25 KHz

 10 KHz

 5 KHz

Core Loss (Watts/Pound)

Flux Density (Gauss)

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

2 mil Square Orthonol (code = 2A)

10 KHz

6 KHz

3 KHz

 1 KHz

 400 Hz

 

Core Loss (Watts/Pound)

Flux Density (Gauss)

1000

100

1000

10K

20K

800
600

400
300

200

80
60

40

30

20

8

6

4

3

2

200

300

400

500

600

700 800 900

2000

3000

4000

5000

6000

7000 8000 9000

10

100

1

1/2 mil Square Orthonol (code = 5A)

100 KHz

50 KHz

25 KHz

 10 KHz

 5 KHz

Core Loss (Watts/Pound)

Flux Density (Gauss)

10

100

1000

10K

20K

8
6

4
3

2

.8
.6

.4

.3

.2

.08

.06

.04

.03

.02

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

.1

1

.01

2 mil Square Permalloy 80 (code = 2D)

10 KHz

15 KHz

6 KHz

3 KHz

 1 KHz

 400 Hz

Core Loss (Watts/Pound)

Flux Density (Gauss)

1 mil Square Permalloy 80 (code = 1D)

10 KHz

5 KHz

100 KHz

50 KHz

25 KHz

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

300 khz

500 khz

100 khz
50 khz

30 khz

20 khz

25 khz

10 khz
5 or 6 khz 

2 khz

3 khz

1 khz
100 hz 
60 hz
500 hz

200 khz

Core Loss (Watts/Pound)

Flux Density (Gauss)

1/2 mil Square Permalloy 80 (code = 5D) 

10 KHz

5 KHz

100 KHz

50 KHz

25 KHz

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

Core Loss (Watts/Pound)

Flux Density (Gauss)

10

100

1000

10K

20K

8
6

4
3

2

.8
.6

.4

.3

.2

.08

.06

.04

.03

.02

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

.1

1

.01

2 mil Supermalloy (code = 2F)

10 KHz

15 KHz

6 KHz

3 KHz

 1 KHz

 400 Hz

Core Loss (Watts/Pound)

Flux Density (Gauss)

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

1 mil Supermalloy (code = 1F)

10 KHz

Flux Density (Gauss)

Flux Density (Gauss)

5 KHz

100 KHz

50 KHz

25 KHz

C

ore Loss (Watts/Pound)

Flux Density (Gauss)

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

1/2 mil Supermalloy (code = 5F)

10 KHz

5 KHz

100 KHz

50 KHz

25 KHz

Core Loss (Watts/Pound)

Flux Density (Gauss)

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

4 mil Magnesil (code = 4K)

 400 Hz

 60 Hz

800 Hz

2000 Hz

 

Core Loss (Watts/Pound)

Flux Density (Gauss)

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

2 mil Magnesil (code = 2K)

 400 Hz

 60 Hz

800 Hz

2000 Hz

5000 Hz

MATERIALS AND APPLICATIONS

CORE LOSS  vs. INDUCTION LEVEL

1 1

Core Loss (Watts/Pound)

Flux Density (Gauss)

10

8
6

4
3

2

.8
.6

.4

.3

.2

.08

.06

.04

.03

.02

100

1000

10K

20K

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

.1

1

.01

2 mil 48 Alloy (code = 2H)

10 KHz

6 KHz

3 KHz

 1 KHz

 400 Hz

Core Loss (Watts/Pound)

Flux Density (Gauss)

1000

100

1000

10K

20K

800
600

400
300

200

80
60

40

30

20

8

6

4

3

2

200

300

400

500

600

700 800 900

2000

3000

4000

5000

6000

7000 8000 9000

10

100

1

1 mil Square Orthonol (code = 1A)

100 KHz

50 KHz

25 KHz

 10 KHz

 5 KHz

Core Loss (Watts/Pound)

Flux Density (Gauss)

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

2 mil Square Orthonol (code = 2A)

10 KHz

6 KHz

3 KHz

 1 KHz

 400 Hz

 

Core Loss (Watts/Pound)

Flux Density (Gauss)

1000

100

1000

10K

20K

800
600

400
300

200

80
60

40

30

20

8

6

4

3

2

200

300

400

500

600

700 800 900

2000

3000

4000

5000

6000

7000 8000 9000

10

100

1

1/2 mil Square Orthonol (code = 5A)

100 KHz

50 KHz

25 KHz

 10 KHz

 5 KHz

Core Loss (Watts/Pound)

Flux Density (Gauss)

10

100

1000

10K

20K

8
6

4
3

2

.8
.6

.4

.3

.2

.08

.06

.04

.03

.02

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

.1

1

.01

2 mil Square Permalloy 80 (code = 2D)

10 KHz

15 KHz

6 KHz

3 KHz

 1 KHz

 400 Hz

Core Loss (Watts/Pound)

Flux Density (Gauss)

1 mil Square Permalloy 80 (code = 1D)

10 KHz

5 KHz

100 KHz

50 KHz

25 KHz

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

300 khz

500 khz

100 khz
50 khz

30 khz

20 khz

25 khz

10 khz
5 or 6 khz 

2 khz

3 khz

1 khz
100 hz 
60 hz
500 hz

200 khz

Core Loss (Watts/Pound)

Flux Density (Gauss)

1/2 mil Square Permalloy 80 (code = 5D) 

10 KHz

5 KHz

100 KHz

50 KHz

25 KHz

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

Core Loss (Watts/Pound)

Flux Density (Gauss)

10

100

1000

10K

20K

8
6

4
3

2

.8
.6

.4

.3

.2

.08

.06

.04

.03

.02

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

.1

1

.01

2 mil Supermalloy (code = 2F)

10 KHz

15 KHz

6 KHz

3 KHz

 1 KHz

 400 Hz

Core Loss (Watts/Pound)

Flux Density (Gauss)

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

1 mil Supermalloy (code = 1F)

10 KHz

Flux Density (Gauss)

Flux Density (Gauss)

5 KHz

100 KHz

50 KHz

25 KHz

C

ore Loss (Watts/Pound)

Flux Density (Gauss)

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

1/2 mil Supermalloy (code = 5F)

10 KHz

5 KHz

100 KHz

50 KHz

25 KHz

Core Loss (Watts/Pound)

Flux Density (Gauss)

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

4 mil Magnesil (code = 4K)

 400 Hz

 60 Hz

800 Hz

2000 Hz

 

Core Loss (Watts/Pound)

Flux Density (Gauss)

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

2 mil Magnesil (code = 2K)

 400 Hz

 60 Hz

800 Hz

2000 Hz

5000 Hz

CORE LOSS  vs. INDUCTION LEVEL

12

Core Loss (Watts/Pound)

Flux Density (Gauss)

10

8
6

4
3

2

.8
.6

.4

.3

.2

.08

.06

.04

.03

.02

100

1000

10K

20K

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

.1

1

.01

2 mil 48 Alloy (code = 2H)

10 KHz

6 KHz

3 KHz

 1 KHz

 400 Hz

Core Loss (Watts/Pound)

Flux Density (Gauss)

1000

100

1000

10K

20K

800
600

400
300

200

80
60

40

30

20

8

6

4

3

2

200

300

400

500

600

700 800 900

2000

3000

4000

5000

6000

7000 8000 9000

10

100

1

1 mil Square Orthonol (code = 1A)

100 KHz

50 KHz

25 KHz

 10 KHz

 5 KHz

Core Loss (Watts/Pound)

Flux Density (Gauss)

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

2 mil Square Orthonol (code = 2A)

10 KHz

6 KHz

3 KHz

 1 KHz

 400 Hz

 

Core Loss (Watts/Pound)

Flux Density (Gauss)

1000

100

1000

10K

20K

800
600

400
300

200

80
60

40

30

20

8

6

4

3

2

200

300

400

500

600

700 800 900

2000

3000

4000

5000

6000

7000 8000 9000

10

100

1

1/2 mil Square Orthonol (code = 5A)

100 KHz

50 KHz

25 KHz

 10 KHz

 5 KHz

Core Loss (Watts/Pound)

Flux Density (Gauss)

10

100

1000

10K

20K

8
6

4
3

2

.8
.6

.4

.3

.2

.08

.06

.04

.03

.02

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

.1

1

.01

2 mil Square Permalloy 80 (code = 2D)

10 KHz

15 KHz

6 KHz

3 KHz

 1 KHz

 400 Hz

Core Loss (Watts/Pound)

Flux Density (Gauss)

1 mil Square Permalloy 80 (code = 1D)

10 KHz

5 KHz

100 KHz

50 KHz

25 KHz

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

300 khz

500 khz

100 khz
50 khz

30 khz

20 khz

25 khz

10 khz
5 or 6 khz 

2 khz

3 khz

1 khz
100 hz 
60 hz
500 hz

200 khz

Core Loss (Watts/Pound)

Flux Density (Gauss)

1/2 mil Square Permalloy 80 (code = 5D) 

10 KHz

5 KHz

100 KHz

50 KHz

25 KHz

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

Core Loss (Watts/Pound)

Flux Density (Gauss)

10

100

1000

10K

20K

8
6

4
3

2

.8
.6

.4

.3

.2

.08

.06

.04

.03

.02

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

.1

1

.01

2 mil Supermalloy (code = 2F)

10 KHz

15 KHz

6 KHz

3 KHz

 1 KHz

 400 Hz

Core Loss (Watts/Pound)

Flux Density (Gauss)

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

1 mil Supermalloy (code = 1F)

10 KHz

Flux Density (Gauss)

Flux Density (Gauss)

5 KHz

100 KHz

50 KHz

25 KHz

C

ore Loss (Watts/Pound)

Flux Density (Gauss)

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

1/2 mil Supermalloy (code = 5F)

10 KHz

5 KHz

100 KHz

50 KHz

25 KHz

Core Loss (Watts/Pound)

Flux Density (Gauss)

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

4 mil Magnesil (code = 4K)

 400 Hz

 60 Hz

800 Hz

2000 Hz

 

Core Loss (Watts/Pound)

Flux Density (Gauss)

100

100

1000

10K

20K

80
60

40
30

20

8
6

4

3

2

.8

.6

.4

.3

.2

200

300

400

500

600

700

800 900

2000

3000

4000

5000

6000

7000

8000 9000

1

10

.1

2 mil Magnesil (code = 2K)

 400 Hz

 60 Hz

800 Hz

2000 Hz

5000 Hz

NOTES

13

TAPE WOUND CORE SIZES

Tape Wound Core Sizes (By Effective Core Area)

14

CORE PART 

NUMBER

NOMINAL CORE  

DIMENSIONS

CASE DIMENSIONS 

(Nylon)

CASES  

AVAILABLE

Path 

Length 

cm

EFFECTIVE CORE AREA (cm

2

)

Window 

Area  

cm

2

WaAc cm

4

 

2 mil  

material

I.D.

O.D.

HT.

I.D. 

MIN

O.D. 

MAX

HT. 

MAX

Alumi-

num

Nylon

0.0005” 0.001” 0.002” 0.004”

50402

in. 

mm.

0.375 

9.5

0.438 

11.1

0.125 

3.2

0.306 

7.8

0.509 

12.9

0.199 

5.0

Yes

Yes

3.25

0.013

0.019

0.022

N/A

0.456

0.010

50107

in. 

mm.

0.500 

12.7

0.563 

14.3

0.125 

3.2

0.432 

11.0

0.632 

16.0

0.199 

5.0

Yes

Yes

4.24

0.013

0.019

0.022

0.023

0.916

0.020

50356

in. 

mm.

0.687 

17.0

0.750 

19.0

0.125 

3.2

0.618 

15.7

0.819 

20.8

0.197 

5.0

Yes

Yes

5.73

0.013

0.019

0.022

0.023

1.914

0.041

50153 

50B12 Mag Amp

in. 

mm.

0.375 

9.5

0.500 

12.7

0.125 

3.2

0.313 

8.0

0.569 

14.4

0.199 

5.0

Yes

Yes

3.49

0.025

0.038

0.043

N/A

0.456

0.020

50154

in. 

mm.

0.438 

11.1

0.563 

14.3

0.125 

3.2

0.369 

9.4

0.632 

16.0

0.199 

5.0

Yes

Yes

3.99

0.025

0.038

0.043

N/A

0.673

0.030

50056 

50B11 Mag Amp

in. 

mm.

0.500 

12.7

0.625 

15.9

0.125 

3.2

0.431 

10.9

0.694 

17.6

0.199 

5.0

Yes

Yes

4.49

0.025

0.038

0.043

0.045

0.916

0.041

50057

in. 

mm.

0.625 

15.9

0.750 

19.0

0.125 

3.2

0.556 

14.1

0.819 

20.8

0.199 

5.0

Yes

Yes

5.48

0.025

0.038

0.043

0.045

1.534

0.066

50155

in. 

mm.

0.438 

11.1

0.563 

14.3

0.250 

6.4

0.369 

9.4

0.632 

16.0

0.324 

8.2

Yes

Yes

3.99

0.050

0.076

0.086

N/A

0.724

0.061

50000 

50B66 Mag Amp

in. 

mm.

0.500 

12.7

0.750 

19.0

0.125 

3.2

0.431 

10.9

0.819 

20.8

0.199 

5.0

Yes

Yes

4.99

0.050

0.076

0.086

0.091

0.916

0.081

50002 

50B10 Mag Amp

in. 

mm.

0.650 

16.5

0.900 

22.9

0.125 

3.2

0.581 

14.8

0.969 

24.6

0.199 

5.0

Yes

Yes

5.98

0.050

0.076

0.086

0.091

1.676

0.142

50011

in. 

mm.

1.000 

25.4

1.250 

31.8

0.125 

3.2

0.921 

23.4

1.329 

33.8

0.209 

5.3

Yes

Yes

8.97

0.050

0.076

0.086

0.091

4.238

0.365

50748

in. 

mm.

2.500 

63.5

2.750 

69.9

0.125 

3.2

2.389 

60.7

2.869 

72.9

0.247 

6.3

Yes

Yes

20.94

0.050

0.076

0.086

0.091

29.407

2.53

50176 

50B45 Mag Amp

in. 

mm.

0.500 

12.7

0.750 

19.0

0.250 

6.4

0.431 

10.9

0.819 

20.8

0.324 

8.2

Yes

Yes

4.99

0.101

0.151

0.171

0.182

0.916

0.157

50033

in. 

mm.

0.625 

15.9

0.875 

22.2

0.250 

6.4

0.556 

14.1

0.944 

24.0

0.324 

8.2

Yes

Yes

5.98

0.101

0.151

0.171

0.182

1.534

0.263

50061

in. 

mm.

0.750 

19.0

1.000 

25.4

0.250 

6.4

0.671 

17.0

1.079 

27.4

0.334 

8.5

Yes

Yes

6.98

0.101

0.151

0.171

0.182

2.273

0.390

50004

in. 

mm.

1.000 

25.4

1.250    

31.8

0.250 

6.4

0.921 

23.4

1.329 

33.8

0.334 

8.5

Yes

Yes

8.97

0.101

0.151

0.171

0.182

4.238

0.724

50076

in. 

mm.

0.625 

15.9

1.000 

25.4

0.188 

4.8

0.546 

13.9

1.079 

27.4

0.272 

6.9

Yes

Yes

6.48

0.113

0.171

0.193

0.205

1.478

0.284

50106

in. 

mm.

0.750 

19.0

1.125 

28.6

0.188 

4.8

0.671 

17.0

1.204 

30.6

0.272 

6.9

Yes

Yes

7.48

0.113

0.171

0.193

0.205

2.273

0.441

50296

in. 

mm.

0.600 

15.2

0.900 

22.9

0.250 

6.4

0.531 

13.5

0.969 

24.6

0.324 

8.2

Yes

Yes

5.98

0.121

0.182

0.206

N/A

1.478

0.304

50323

in. 

mm.

2.500 

63.5

2.800 

71.1

0.250 

6.4

2.329 

59.2

2.971 

75.5

0.410 

10.4

No

Yes

21.14

0.121

0.182

0.206

0.218

29.407

6.06

50007

in. 

mm.

0.625 

15.9

1.000 

25.4

0.250 

6.4

0.546 

13.9

1.079 

27.4

0.334 

8.5

Yes

Yes

6.48

0.151

0.227

0.257

0.272

1.478

0.380

50084

in. 

mm.

0.750 

19.0

1.125 

28.6

0.250 

6.4

0.671 

17.0

1.204 

30.6

0.329 

8.4

Yes

Yes

7.48

0.151

0.227

0.257

0.272

2.273

0.582

50029

in. 

mm.

1.000 

25.4

1.375 

34.9

0.250 

6.4

0.901 

22.9

1.474 

37.4

0.354 

9.0

Yes

Yes

9.47

0.151

0.227

0.257

0.272

4.438

1.09

50168

in. 

mm.

0.750 

19.0

1.000 

25.4

0.375 

9.5

0.671 

17.0

1.079 

27.4

0.459 

11.6

Yes

Yes

6.98

0.151

0.227

0.257

0.272

2.273

0.582

Note: Mag Amp cores available in 1 mil (0.001") Square Permalloy 80 - 1D and 1/2 mil (.0005") Square Permalloy 80 - 5D 

MATERIALS AND APPLICATIONS

TAPE WOUND CORE SIZES

15

CORE PART 

NUMBER

NOMINAL CORE  

DIMENSIONS

CASE DIMENSIONS 

(Nylon)

CASES  

AVAILABLE

Path 

Length 

cm

EFFECTIVE CORE AREA (cm

2

)

Window 

Area  

cm

2

WaAc cm

4

 

2 mil  

material

I.D. O.D.

HT.

I.D. 

MIN

O.D. 

MAX

HT. 

MAX

Alumi-

num

Nylon

0.0005” 0.001”

0.002”

0.004”

50032

in 

mm.

1.000 

25.4

1.500 

38.1

0.250 

6.4

0.901 

22.9

1.599 

40.6

0.354 

9.0

Yes

Yes

9.97

0.202

0.303

0.343

0.363

4.238

1.45

50030

in. 

mm.

1.250 

31.8

1.750 

44.4

0.250 

6.4

1.149 

29.2

1.851 

47.0

0.357 

9.1

Yes

Yes

11.96

0.202

0.303

0.343

0.363

6.815

2.24

50391

in. 

mm.

1.000 

25.4

1.250 

31.8

0.500 

12.7

0.906 

23.0

1.344 

34.1

0.599 

15.2

No

Yes

8.97

0.202

0.303

0.343

0.363

4.435

1.52

50094

in. 

mm.

0.625 

15.9

1.000 

25.4

0.375 

9.5

0.546 

13.9

1.079 

27.4

0.459 

11.6

Yes

Yes

6.48

0.224

0.340

0.386

0.408

1.534

0.592

50034

in. 

mm.

0.750 

19.0

1.125 

28.6

0.375 

9.5

0.671 

17.0

1.204 

30.6

0.459 

11.6

Yes

Yes

7.48

0.224

0.340

0.386

0.408

2.273

0.876

50181

in. 

mm.

0.875 

22.2

1.250 

31.8

0.375 

9.5

0.796 

20.2

1.329 

33.8

0.459 

11.6

Yes

Yes

8.47

0.224

0.340

0.386

0.408

3.160

1.22

50504

in. 

mm.

1.125 

28.6

1.500 

38.1

0.375 

9.5

1.036 

26.3

1.599 

40.6

0.479 

12.2

Yes

Yes

10.47

0.224

0.340

0.386

0.408

5.478

2.12

50133

in. 

mm.

0.650 

16.5

1.150 

29.2

0.375 

9.5

0.571 

14.5

1.229 

31.2

0.459 

11.6

Yes

Yes

7.18

0.299

0.454

0.514

0.545

1.676

0.861

50188

in. 

mm.

0.750 

19.0

1.250 

31.8

0.375 

9.5

0.671 

17.0

1.329 

33.8

0.459 

11.6

Yes

Yes

7.98

0.299

0.454

0.514

0.545

2.238

1.15

50383

in. 

mm.

0.875 

22.2

1.375 

34.9

0.375 

9.5

0.776 

19.7

1.474 

37.4

0.479 

12.2

Yes

Yes

8.97

0.299

0.454

0.514

0.545

3.160

1.63

50026

in. 

mm.

1.000 

25.4

1.500 

38.1

0.375 

9.5

0.901 

22.9

1.599 

40.6

0.479 

12.2

Yes

Yes

9.97

0.299

0.454

0.514

0.545

4.238

2.18

50038

in. 

mm.

1.000 

25.4

1.500 

38.1

0.500 

12.7

0.901 

22.9

1.599 

40.6

0.604 

15.3

Yes

Yes

9.97

0.398

0.605

0.689

0.726

4.238

2.91

50035

in. 

mm.

1.250 

31.8

1.750 

44.4

0.500 

12.7

1.149 

29.2

1.851 

47.0

0.607 

15.4

Yes

Yes

11.96

0.398

0.605

0.689

0.726

6.815

4.67

50055

in. 

mm.

1.500 

38.1

2.000 

50.8

0.500 

12.7

1.401 

35.6

2.099 

53.3

0.604 

15.3

Yes

Yes

13.96

0.398

0.605

0.689

0.726

9.924

6.81

50345

in. 

mm.

1.750 

44.4

2.250 

57.2

0.500 

12.7

1.619 

41.1

2.381 

60.5

0.627 

15.9

Yes

Yes

15.95

0.398

0.605

0.689

0.726

13.787

9.46

50017

in. 

mm.

2.000 

50.8

2.500 

63.5

0.500 

12.7

1.869 

47.5

2.631 

66.8

0.627 

15.9

Yes

Yes

17.95

0.398

0.605

0.689

0.726

18.182

12.5

50425

in. 

mm.

1.250 

31.80

2.000 

50.8

0.375 

9.5

1.134 

28.8

2.116 

53.7

0.492 

12.5

Yes

Yes

12.96

0.448

0.681

0.771

0.817

6.815

5.26

50555

in. 

mm.

1.250 

31.8

2.250 

57.1

0.500 

12.7

1.119 

28.4

2.381 

60.5

0.627 

15.9

Yes

Yes

13.96

0.796

1.210

1.371

1.452

6.699

9.19

50001

in. 

mm.

1.500 

38.1

2.500 

63.5

0.500 

12.7

1.369 

34.8

2.631 

66.8

0.627 

15.9

Yes

Yes

15.95

0.796

1.210

1.371

1.452

9.640

13.2

50103

in. 

mm.

2.000 

50.8

3.000 

76.2

0.500 

12.7

1.869 

47.5

3.131 

79.5

0.627 

15.9

Yes

Yes

19.94

0.796

1.210

1.371

1.452

17.894

24.5

50128

in. 

mm.

2.5 

63.5

3.5 

88.8

0.500 

12.7

2.369 

60.2

3.631 

92.2

0.627 

15.9

Yes

Yes

23.93

0.796

1.210

1.371

1.452

28.678

39.3

TAPE CORE DESIGN

16

Materials

Saturation 

Flux Density 

in Tesla

Curie  

Temp. 

˚C

Tape  

Thickness

Frequency of 

Operation

Square Permalloy D 

79% Ni 4% Mo 17% Fe

0.66 – 0.82 T

460 ˚C

.0005"

.001"

.002"

.004"

40 kHz

20 kHz

10 khz

  5 kHz

Round Permalloy R 

79% Ni 4% Mo 17% Fe

0.66 – 0.82 T

460 ˚C

.001"

.002"

.004"

20 kHz

10 khz

  5 kHz

Supermalloy F

79% Ni 4% Mo 17% Fe

0.65 – 0.82 T

460 ˚C

.0005"

.001"

.002"

.004"

80 kHz 

50 kHz

25 khz

10 kHz

Magnesil K 

97% Fe 3% Si

1.50 – 1.80 T

750 ˚C

.001"

.002"

5 khz

2 kHz

Square Orthonol

50% Ni  50% Fe

1.42 – 1.58 T

500 ˚C

.0005"

.001"

.002"

.004"

20 kHz

10 khz

  5 kHz

1.5 kHz

Alloy 48 H

50% Ni 50% Fe

1.15  - 1.40 T

500 ˚C

.002"

.004"

20 kHz

10 khz

   

TRANSFORMER DESIGN  
60 H

z

-300

 

k

H

z

 

MATERIAL AND CORE SELECTION

Design to achieve:    
Minimum size and weight.  Maximum Efficiency.  Minimize cost.

1

 

  From the operating specifications determine the following transformer specifications: 

Operating frequency —

 f  in Hz

 

V

p

—Primary voltage in 

V

rms

 ; 

V

s

—Secondary voltage in 

V

rms

 

 

I

p

—Primary current in Amps; 

I

s

—Secondary current in Amps

2

  Select a wire gauge to support the RMS current in the primary and secondary.   

See the wire table page 22.  

Take note of the wire area  A

w

 in cm

2

3

    Select the proper material and thickness based upon the frequency of operation.

Select the flux density that is suited to the material and the application.  Saturating transformers 

will use the saturation flux density of the material.  For standard converters flux density is limited 

to 50 – 80% of the saturation flux density.  Lower the operating flux density if you need to limit 

the core losses.  For example, from the Core Loss chart on page 11 one mil Permalloy operating 

at 0.1 Tesla, 1 kGauss, at 100 kHz will have losses of 20 watts per lb.  Reducing the flux density 

or the frequency will lower the losses.

4

 

  Select the operating flux density (B) and solve the following equation for W

a

A

c

 (area 

product):

 W

a

A

c

 = (A

w

 V

p

 x10

8

)/(4.0 B

m

 K f)    

 

Use the values as noted above for A

w

, V

p

, B

m

, and f in Hz.  

 

4.0 for a square wave; 4.4 for sine wave excitation

 W

a

 = winding area of core (cm

2

)

 A

c

 = effective core cross sectional area (cm

2

)

 K

W

 = winding factor. K is 0.20 for a common two winding transformer. If the 

transformer is a self-saturating Royer or Jensen type inverter use K = 0.15 to allow for 

the space required for the switching windings.

5

  Select a core that has a W

a

A

c

 value greater than the value that you calculated.  W

a

A

c

  

values for Magnetics tape wound cores are listed in the Core Sizes Tables beginning on 

page 14.

From the Core Sizes, note the cross sectional area (A

c

) of the selected core and the tape 

thickness.  Use this value in the following equation to solve for the number of primary turns 

(Np).
N

p

 = (V

p

x10

8

)/(4.0 B

m

 f A

c

)   N

s

 = ( V

s

/V

p

) x N

p

Design Example:

•

 A core is needed for a 240 watt transformer.  

• 

Primary input is 120 V at a current of 2A; Secondary is required to be 48 V out at 5 A.     

  The frequency of operation is 10 kHz. 

• 

1 mil Orthonol is selected at an operating flux density of 7,250 Gauss. 

• 

Wire chosen for the primary is AWG # 20;  W

a

 is 0.00632 cm

2

; 

• 

Wire chosen for the secondary is AWG # 15; W

a

 is 0.0191 cm

2

. 

• 

W

a

A

c

 = (A

w

 V

p

x10

8

)/(4.0 B

m

 K

w

 f)  = (0.00632 x 120 V x 10

8

)/(4.0 x 7,250 x  

  0.2 x 10,000) = 1.31 

• 

The 01500261A core is chosen.  W

a

A

c

  of the 01500261A core, given in the chart, is  

  2.18 for 2 mil material, multiply the window area x the A

e

 for 1 mil material to arrive at  

  a W

a

A

c 

of 1.92 for 1 mil. material.

• 

OD nylon case = 40.6 mm ID = 22.9 mm HT = 12.2 mm 

• 

N

p

 = (V

p

x10

8

)/(4.0 B

m

 f A

c

) = (120 V x 10

8

)/(4.0 x 7,250 x 10,000 x 0.454) = 91

• 

N

s

 = (48 V/ 120 V ) x 91 = 36.4 = 37 turns.  91 x 0.00632 cm

2

 = 0.575 cm

2

,   

 

  37 x  0.0191 cm

2

 = 0.7067 cm

2

• 

0.575 cm

2

 + 0.7067 cm

2

 = 1.28 cm

2

.  Window area is 4.238 cm

2

;  Window fill = 30%.

• 

RMS current density 5A/ 0.0191 cm

2

 = 262 A/cm

2

     2A/0.00632 = 316 A/cm

2

• 

MLT estimated for a toroid = 0.8 ( OD + 2 HT) = 0.8 (40.6 mm + 2 x(12.2 mm)) =  

  52 mm/turn 

• 

Copper resistance MLT = 52 mm/turn 

• 

Resistance in Ohms =  0.052 m x 91 turns x 0.03323 Ohms/m = 0.157 Ohms  AWG #20 

  

0.052 m x 37 turns x 0.01040 Ohms/m = 0.020 Ohms  AWG #15

• 

[5

2

 x (0.020 Ohms) = 0.500 Watts primary] + [2

2

 x ( 0.166 Ohms) = 0.628 Watts  

 secondary]

• 

Total DC copper losses = 1.1 Watts.

• 

Determine the Flux density to calculate core losses V = 4 N

p

 A

e

 f B x 10

 -8

• 

120 V = 4.0  (91) (0.454) (10,000) B (10

 -8

) ; B= (120 V) / (4.0  X 91 turns X  

  10,000 Hz x 10

 -8

) = 7261 Gauss

• 

B = 7261 Gauss, f = 10,000 Core loss curve for 1 mil A is about 60 W/lb  the core  

  weighs 0.0819 lb

• 

Core weight = l

e

 x A

e

 x  C core wt. constant = 9.97 cm  x 0.454 cm

2

 x 0.0181=  

  0.0819 lb x 60 W/lb = 4.9 W
Efficiency estimate 240/246 Watts = 97.5%.  

NOTE:
Core weight can be calculated (in pounds) using:
Weight = l

e

 x A

c

 x C, where

C = 0.0192 for Permalloy (80% Nickel) materials

0.0181 for Orthonol and 48 Alloy

0.0169 for Magnesil

MATERIALS AND APPLICATIONS

BOBBIN CORES

17

Below is a quick reference for available combinations of materials, cases, and gauges.

Material

Code

Materials

Available  

Cases/Coatings*

Gauges (Thickness)

0.000125"

1/8 mil

(Gauge Code 9)

0.00025"

1/4 mil

(Gauge Code 0)

0.0005"

1/2 mil

(Gauge Code 5)

0.001"

1 mil

(Gauge Code 1)

A

Square Orthonol

stainless steel with epoxy coating

X

X

X

D

Square Permalloy 80

stainless steel with epoxy coating

X

X

X

X

F

Supermalloy

stainless steel with epoxy coating

X

X

  

APPLICATIONS

Because of their temperature stability, low coercive values and high saturation flux densities, 

as well as high peak permeabilities and high squareness, Magnetics Bobbin Cores are ideal 

for:

> High Frequency Magnetic 

> Pulse Transformers 

   Amplifiers 
> Flux Gate Magnetometers  > Current Transformers
> Harmonic Generators 

> Analog Counters and Timers

> Oscillators 

> Inverters

Magnetics Bobbin Cores are miniature tape cores made from ultra-thin (0.000125" to 0.001" thick) strip material wound on nonmagnetic 

stainless steel bobbins. Bobbin Cores are generally manufactured from Permalloy 80 and Orthonol. Covered with protective caps and then 

epoxy coated, Bobbin Cores can be made as small as 0.05" ID and with strip widths down to 0.032".

*Flux capacity is the area under the open circuit output waveform, measured in Maxwells  

  when the core is switched from positive residual to negative saturation.

HOW TO ORDER

Each miniature core is coded by a part number, which describes it:

8 0 5 3 1 0 D M A

Standard Part

Material Code

Bobbin Core Code

Core Size

Gauge Code

8 0 5 3 1 0 D 0 1 0 0 X X

Customer-defined

Special Specification

Gauge Code

Flux Capacity (Maxwell)*

OR

Material Code

Bobbin Core Code

Core Size

BOBBIN CORE SIZES

18

CORE PART 

NUMBER

CASE DIMENSIONS

SQUARE PERMALLOy 80 FLUX CAPACITy 

MAXWELLS

SQUARE ORTHONOL FLUX CAPACITy 

MAXWELLS

I.D. 

MIN

O.D. 

MAX

HT. 

MAX

MEAN 

LENGTH 

cm

WINDOW 

AREA  

cm

2

0.000125” 0.00025” 0.0005” 0.001” 0.00025” 0.0005”

0.001”

Core area, A

e

 cm

2

Core area, A

e

 cm

2

80521 * MA

in.

0.097

0.225

0.120

1.20

0.051

0.002

0.0033

0.0053

0.0066

0.0033

0.0053

0.0066

mm.

2.46

5.72

3.05

30

50

80

100

100

160

200

80550 * MA

in.

0.128

0.255

0.120

1.45

0.086

mm.

3.25

6.48

3.05

80505 * MA

in.

0.160

0.290

0.120

1.70

0.137

mm.

4.06

7.37

3.05

80512 * MA

in.

0.222

0.350

0.120

2.20

0.255

mm.

5.64

8.89

3.05

Core area, A

e

 cm

2

Core area, A

e

 cm

2

80529 * MA

in.

0.097

0.225

0.185

1.20

0.051

0.004

0.0066

0.0105

0.0132

0.0066

0.0105

0.0132

mm.

2.46

5.72

4.70

60

100

160

200

200

320

400

80544 * MA

in.

0.125

0.255

0.185

1.45

0.086

mm.

3.18

6.48

4.70

80523 * MA

in.

0.160

0.290

0.185

1.70

0.137

mm.

4.06

7.37

4.70

80530 * MA

in.

0.222

0.350

0.185

2.20

0.255

mm.

5.64

8.89

4.70

80524 * MA

in.

0.285

0.415

0.185

2.70

0.425

mm.

7.24

10.54

4.70

80531 * MA

in.

0.345

0.480

0.185

3.20

0.620

mm.

8.76

12.19

4.70

80608 * MA

in.

0.405

0.540

0.185

3.70

0.850

mm. 10.29

13.72

4.70

80609 * MA

in.

0.47

0.605

0.185

4.20

1.140

mm. 11.94

15.49

4.70

Core area, A

e

 cm

2

Core area, A

e

 cm

2

80558 * MA

in.

0.222

0.385

0.185

2.30

2.550

0.006

0.010

0.016

0.0198

0.010

0.016

0.0198

mm.

5.64

9.78

4.70

90

150

240

300

300

480

600

80581 * MA

in.

0.285

0.445

0.185

2.80

0.425

mm.

7.24

11.30

4.70

80610 * MA

in.

0.345

0.505

0.185

3.30

0.620

mm.

8.89

12.95

4.70

*Gauge Code and Material Code are inserted here.

MATERIALS AND APPLICATIONS

BOBBIN CORE SIZES

19

CORE PART 

NUMBER

CASE DIMENSIONS

SQUARE PERMALLOy 80 FLUX CAPACITy 

MAXWELLS

SQUARE ORTHONOL FLUX CAPACITy 

MAXWELLS

I.D. 

MIN

O.D. 

MAX

HT. 

MAX

MEAN 

LENGTH 

cm

WINDOW 

AREA  

cm

2

0.000125” 0.00025” 0.0005” 0.001” 0.00025”

0.0005”

0.001”

Core area, A

e

 cm

2

Core area, A

e

 cm

2

80611 * MA

in.

0.220 0.415 0.185

2.40

0.255

0.008

0.0133

0.021

0.0264

0.0133

0.021

0.0264

mm.

5.59

10.54

4.70

120

200

320

400

400

640

800

80598 * MA

in.

0.285 0.480 0.185

2.90

0.425

mm.

7.24

12.19

4.70

80516 * MA

in.

0.345 0.540 0.185

3.40

0.620

mm.

8.76

13.72

4.70

80612 * MA

in.

0.405 0.605 0.185

3.90

0.850

mm. 10.29 15.37

4.70

80588 * MA

in.

0.470 0.665 0.185

4.40

1.140

mm. 11.94 16.89

4.70

Core area, A

e

 cm

2

Core area, A

e

 cm

2

80613 * MA

in.

0.285 0.510 0.185

3.00

0.425

0.010

0.0165

0.0265

0.033

0.0165

0.0265

0.033

mm.

7.24 12.95

4.70

150

250

400

500

500

800

1,000

80606 * MA

in.

0.345 0.57

0.185

3.50

0.620

mm.

8.76 14.48

4.70

80614 * MA

in.

0.405 0.63

0.185

4.00

0.850

mm. 10.29 16.00

4.70

80615 * MA

in.

0.470 0.695 0.185

4.50

1.140

mm. 11.94 17.65

4.70

Core area, A

e

 cm

2

Core area, A

e

 cm

2

80560 * MA

in.

0.217 0.385 0.320

2.30

0.245

0.012

0.020

0.032

0.0395

0.020

0.032

0.0395

mm.

5.51

9.78

8.13

180

300

480

600

600

960

1,200

80539 * MA

in.

0.280 0.445 0.320

2.80

0.410

mm.

7.11 11.30

8.13

80517 * MA

in.

0.342 0.510 0.320

3.30

0.602

mm.

8.69 12.95

8.13

80616 * MA

in.

0.400 0.570 0.320

3.80

0.830

mm. 10.16 14.48

8.13

80617 * MA

in.

0.465 0.630 0.320

4.30

1.120

mm. 11.81 16.00

8.13

Core area, A

e

 cm

2

Core area, A

e

 cm

2

80600 * MA

in.

0.280 0.480 0.320

2.90

0.410

0.016

0.0265

0.042

0.053

0.0265

0.042

0.053

mm.

7.11 12.19

8.13

240

400

640

800

800

1,280

1,600

80618 * MA

in.

0.342 0.540 0.320

3.40

0.602

mm.

8.69 13.72

8.13

80619 * MA

in.

0.400 0.605 0.320

3.90

0.830

mm. 10.16 15.37

8.13

80525 * MA

in.

0.465 0.665 0.320

4.40

1.120

mm. 11.81 16.89

8.13

 

20

BOBBIN CORE DESIGN

BOBBIN CORE DESIGN 

Basic properties of a bobbin core are its size, material type and thickness, and its flux capacity. The size determines the maximum number of turns of wire that can be wound on the core and the dc 

winding resistance.  The operating frequency and the losses that can be tolerated in the circuit determine the type of material selected and the tape thickness.  The flux capacity, or volt second area, 

of the core determines its output per turn of wire and the voltage the core can support.  Bobbin cores were designed for pulse applications.  It is for this reason that the test conditions and measured 

characteristics supply information about Ts, switching time, Core One Flux, the amount of flux switched in one cycle, and squareness. 
Flux capacities in Maxwells for each core are shown in the Bobbin Core Sizes Table.  Nomograms related to core selection have been developed.  For power applications a graph of Power handling vs 

Window Area Flux Product allows the designer to select a core based upon operating frequency and output power.  Another graph illustrates switching time vs. H in Oersteds for switching applications.  

Core loss curves for the material will allow the designer to calculate core losses.  Please contact Sales Engineering at Magnetics for additional bobbin core design information and to receive the families 

of curves.

* If operating flux density is reduced, frequencies can be extended upwards from those listed. 

Square Permalloy has lower losses. Square Orthonol has greater flux capacity. 

Thickness (mils)

*Square Orthonol

*Square Permalloy 80

1

up to 8,000 Hz

up to 20,000 Hz

 1/2

up to 20,000 Hz

up to 40,000 Hz 

 1/4

up to 40,000 Hz

up to 80,000 Hz 

 1/8

above 80,000 Hz

   

Square Permalloy 80 (Material Code D)

Material Thickness (Mils)

ø

1 

% of Nominal

ø

0 

/ø

1

 Max.

B

r

 / B

m

  (min)

T

S

 (micro-sec) Max.

 1/8

±10%

0.050

90.5%

1.25

 1/4

±10%

0.065

87.8%

1.60

 1/2

±10%

0.090

83.5%

3.50

1

±15%

0.120

78.6%

8.00

   

Square Orthonol (Material Code A)

Material Thickness (Mils)

ø

1 

% of Nominal

ø

0 

/ø

1

 Max.

B

r

 / B

m

  (min)

T

S

 (micro-sec) Max.

 1/4

±10%

0.050

90.5%

5.0

 1/2

±10%

0.050

90.5%

8.0

1

±15%

0.050

90.5%

18.0

   

Select the bobbin core best suited for your application:

Select the material type and thickness.  Based on operation at or near saturation flux density, 

the following is a guide in selecting the proper thickness of materials for various frequency 

ranges:

MATERIALS AND APPLICATIONS

BOBBIN CORE TESTING

BOBBIN CORE TESTING 
Integrated One Flux (ø

1

)

The integrated one flux is the value in Maxwells of the response produced when the one 

output voltage is passed through a calibrated integrator. It is the area under the one output 

voltage waveform, and is the flux switched when the core is driven from positive residual to 

negative saturation. Reference Figure #2.

Squareness (B

r

/B

m

)

The squareness is the ratio of the residual flux of a core to the saturation flux of a core.

Switching Time (T

s

)

The switching time is that time interval between the point where the core output has risen 

to 10% of the core one output voltage and the point where the core output has decreased to 

10% of the one output voltage. Reference Figure #3.

Noise to Signal Ratio (ø

0

/ø

1

)

The integrated zero flux, 

ø

0

, measured in Maxwells is the integral of the area under the Open 

circuit zero waveform when the flux is switched from negative residual to negative saturation. 

Divide this value by 

ø

1

 to obtain 

ø

0

/

ø

1

.

Fig 3: Integrated Core Response

Ø

p

Ø

0

Ø

1

Fig 2: Open Circuit Outputs and Switching Time

10%

10%

V

1 

V

0

T

S

Fig 3: Integrated Core Response

Ø

p

Ø

0

Ø

1

Fig 2: Open Circuit Outputs and Switching Time

10%

10%

V

1 

V

0

T

S

Fig 2: Integrated Core Response

Fig 3: Open Circuit Outputs and Switching Time

21

MATERIALS AND APPLICATIONS

22

WIRE TABLE

AWG  

Wire  

Size 

Resistance 

W / meter 

(x.305, W/ft)

Wire  

OD(cm) 

 Hvy Bld

Wire Area

Current Capacity,  Amps  

(by columns of amps / sq.cm.)

 Circ.  

Mils

sq. cm. 

(x0.001)

200

400

600

800

8

0.00207

0.334

18,000

91.2

16.5

33.0

49.5

66.0

9

0.00259

0.298

14,350

72.7

13.1

26.2

39.3

52.4

10

0.00328

0.267

11,500

58.2

10.4

20.8

31.2

41.6

11

0.00413

0.238

9,160

46.4

8.23

16.4

24.6

32.8

12

0.00522

0.213

7,310

37.0

6.53

13.1

19.6

26.1

13

0.00656

0.1902

5,850

29.6

5.18

10.4

15.5

20.8

14

0.00827

0.1714

4,680

23.7

4.11

8.22

12.3

16.4

15

0.01043

0.1529

3,760

19.1

3.26

6.52

9.78

13.0

16

0.01319

0.1369

3,000

15.2

2.58

5.16

7.74

10.3

17

0.01657

0.1224

2,420

12.2

2.05

4.10

6.15

8.20

18

0.0210

0.1095

1,940

9.83

1.62

3.25

4.88

6.50

19

0.0264

0.0980

1,560

7.91

1.29

2.58

3.87

5.16

20

0.0332

0.0879

1,250

6.34

1.02

2.05

3.08

4.10

21

0.0420

0.0785

1,000

5.07

0.812

1.63

2.44

3.25

22

0.0531

0.0701

810

4.11

0.640

1.28

1.92

2.56

23

0.0666

0.0632

650

3.29

0.511

1.02

1.53

2.04

24

0.0843

0.0566

525

2.66

0.404

0.808

1.21

1.62

25

0.1063

0.0505

425

2.15

0.320

0.61

0.962

1.28

26

0.1345

0.0452

340

1.72

0.253

0.506

0.759

1.01

27

0.1686

0.0409

270

1.37

0.202

0.403

0.604

0.806

28

0.0653

0.0366

220

1.11

0.159

0.318

0.477

0.636

29

0.266

0.0330

180

0.912

0.128

0.255

0.382

0.510

30

0.341

0.0295

144

0.730

0.100

0.200

0.300

0.400

31

0.430

0.0267

117

0.593

0.0792

0.158

0.237

0.316

32

0.531

0.0241

96.0

0.487

0.0640

0.128

0.192

0.256

33

0.676

0.0216

77.4

0.392

0.0504

0.101

0.152

0.202

34

0.856

0.01905

60.8

0.308

0.0397

0.0794

0.119

0.159 

35

1.086

0.01702

49.0

0.248

0.0314

0.0627

0.0940

0.125

36

1.362

0.01524

39.7

0.201

0.0250

0.0500

0.0750

0.100

37

1.680

0.01397

32.5

0.165

0.0203

0.0405

0.0608

0.0810

38

2.13

0.01245

26.0

0.132

0.0160

0.0320

0.0480

0.0640

39

2.78

0.01092

20.2

0.102

0.0123

0.0245

0.0368

0.0490

40

3.51

0.00965

16.0

0.081

0.00961

0.0192

0.0288

0.0384

41

4.33

0.00864

13.0

0.066

0.00785

0.0157

0.0236

0.0314

42

5.45

0.00762

10.2

0.052

0.00625

0.0125

0.0188

0.0250

43

7.02

0.00686

8.40

0.043

0.00484

0.00968

0.0145

0.0194

44

8.50

0.00635

7.30

0.037

0.00400

0.00800

0.0120

0.0160

45

10.99

0.00546

5.30

0.027

0.00309

0.00618

0.00927

0.0124

46

13.81

0.00498

4.40

0.022

0.00248

0.00496

0.00744

0.00992

47

17.36

0.00452

3.60

0.018

0.00194

0.00388

0.00582

0.00776

48

22.1

0.00394

2.90

0.015

0.00175

0.00350

0.00525

0.00700

49

27.6

0.00353

2.25

0.011

0.00150

0.00300

0.00450

0.00600

50

34.7

0.00325

1.96

0.010

0.00098

0.00195

0.00292

0.00390

   

MATERIALS AND APPLICATIONS

OTHER PRODUCTS FROM MAGNETICS

FERRITE CORES

Ferrite Cores are manufactured for a wide variety of applications. Magnetics has developed 

and produces the leading MnZn ferrite materials for power transformers, power inductors, 

wideband transformers, common mode chokes, and many other applications. In addition to 

offering the leading materials, other advantages of ferrites from Magnetics include: the full 

range of standard planar E and I Cores; rapid prototyping capability for new development; the 

widest range of toroid sizes in power and high permeability materials; standard gapping to 

precise inductance or mechanical dimension; wide range of coil former and assembly hardware 

available; and superior toroid coatings available in several options.

POWER MATERIALS

Five low loss materials, R, P, F, L and T, are engineered for optimum frequency and temperature 

performance in power applications. Magnetics’ materials provide superior saturation, high 

temperature performance, low losses, and product consistency. 

Shapes:

 E cores, Planar E cores, ETD, EC, U cores, I cores, PQ, Planar PQ, RM, Toroids, Pot 

cores, RS (roundslab), DS (double slab), EP, Special shapes 

Applications:

 Telecomm, Computer, Commercial and Consumer Power Supplies, 

Automotive, DC-DC Converters, Telecomm Data Interfaces, Impedance Matching Transformers, 

Handheld Devices, High Power Control (gate drive), Computer Servers, Distributed Power 

(DC-DC), EMI Filters, Aerospace, Medical.

HIGH PERMEABILITY MATERIALS

Two high permeability materials (J, 5,000µ, and W, 10,000µ) are engineered for optimum 

frequency and impedance performance in signal, choke and filter applications. Magnetics’ 

materials provide superior loss factor, frequency response, temperature performance, and 

product consistency.

Shapes:

 Toroids, E cores, U cores, RM, Pot cores, RS (round-slab), DS (double slab), EP, 

Special shapes 

Applications:

 Common Mode Chokes, EMI Filters, Other Filters, Current Sensors, Telecomm 

Data Interfaces, Impedance Matching Interfaces, Handheld Devices, Spike Suppression, Gate 

Drive Transformers, Pulse Transformers, Current Transformers, Broadband Transformers

23

POWDER CORES

Powder cores are excellent as low loss inductors for switched-mode power supplies, switching 

regulators and noise filters. Most core types can be shipped immediately from stock.

Kool Mμ

®

 powder cores have a higher energy storage capacity than MPP cores and are 

available in six permeabilities from 14µ through 125µ. Kool Mµ is available in a variety of 

core types, for maximum flexibility. Toroids offer compact size and self-shielding. E cores and 

U cores afford lower cost of winding, use of foil windings, and ease of fixturing. Very large 

cores and structures are available to support very high current applications. These include 

toroids and racetrack shapes up to 102 mm, 133 mm and 165 mm; jumbo E cores; stacked 

shapes; and blocks.

Molypermalloy Powder Cores (MPP)

 are available in ten permeabilities ranging from 

14µ through 550µ, and have guaranteed inductance limits of ±8%. Insulation on the cores 

is a high dielectric strength finish not affected by normal potting compounds and waxes. 

Over thirty sizes include O.D.s from 3.56 mm to 165.1 mm. Standard cores include either 

temperature stabilized (as wide as -65° C to 125° C for stable operation) or standard 

stabilization.

High Flux

 powder cores have a much higher energy storage capacity than MPP cores and 

are available in six permeabilities from 14µ through 160µ. High Flux cores are available in 

sizes identical to MPP cores.

XF

lux

®

 distributed air gap cores are made from 6.5% silicon iron powder and are available 

in 26µ, 40µ and 60µ. A true high temperature material, with no thermal aging, XF

lux

 offers 

lower losses than powder iron cores and superior DC Bias performance. The soft saturation 

of XF

lu

x material offers an advantage over ferrite cores. XF

lux

 cores are ideal for low and 

medium frequency chokes where inductance at peak current is critical. Toroids are available in 

sizes up to 133 mm and blocks with lengths of 50, 60, and 80 mm.

AmoFlux

®

 is a new powder alloy distributed gap material that is ideal for power factor 

correction (PFC) and output chokes. This alloy starts with low core loss ribbon that is 

pulverized into powder and then pressed into a toroid. By converting the ribbon into a powder, 

the resulting AmoFlux cores have the same excellent properties, including soft saturation, as 

Magnetics other powder core materials: Kool Mµ

®

, MPP, High Flux, and XF

lux

®

. What makes 

this amorphous powder core material unique is the combination of low core loss and high DC 

bias. These attributes make AmoFlux an excellent choice for computer, server, and industrial 

power supplies that require PFC or output chokes.

OTHER PRODUCTS FROM MAGNETICS

CUSTOM COMPONENTS

Magnetics offers unique capabilities in the design and manufacture of specialized components 

fabricated from magnetic materials in many sizes and shapes. 
Ferrites can be pressed in block form and then machined into intricate shapes. Where large 

sizes are required, it is possible to assemble them from two or more smaller machined or 

pressed sections. The variety of sizes and shapes is limitless.

Surface Grinding 

Hole Drilling

Cutting, Slicing, Slotting  Special Machining
ID and OD Machining   Assembly of Smaller Parts

Without sacrificing magnetic properties, many operations can be performed on ferrites, while 

maintaining strict dimensional or mechanical tolerances:
Standard catalog items can also be modified, as needed, to fit your requirements.
Contact the Magnetics Sales Department for more information.

RAPID PROTOTYPING SERVICE

Magnetics’ world-class materials offer unique and powerful advantages to almost any 

application. An even greater competitive edge can be gained through innovations in new 

core shapes and custom geometries, and Magnetics is poised to help. Our Rapid Prototyping 

Service can quickly make a wide variety of core shapes in Ferrite, MPP, High Flux, Kool 

Mµ

®

, AmoFlux

®

, or XF

lux

®

. Our rapid turnaround time results in a shorter design period, 

which gets your product to market faster. Plus, our Sales Engineers may be able to provide 

design assistance that could lead to a lower piece price. To learn more about how our Rapid 

Prototyping Service can help you shorten your design cycle, contact a Magnetics Sales 

Engineer.

WARRANTY

All standard parts are guaranteed to be free from defects in material and workmanship, and 

are warranted to meet the Magnetics published specification. No other warranty, expressed 

or implied, is made by Magnetics. All special parts manufactured to a customer’s specification 

are guaranteed only to the extent agreed upon, in writing, between Magnetics and the user.

Magnetics will repair or replace units under the following 
conditions:

1. The buyer must notify Magnetics, Pittsburgh, PA 15238 in writing, within 30 days of the 

receipt of material, that he requests authorization to return the parts. A description of the 

complaint must be included.
2. Transportation charges must be prepaid.
3. Magnetics determines to its satisfaction that the parts are defective, and the defect is not 

due to misuse, accident or improper application.
Magnetics liability shall in no event exceed the cost of repair or replacement of its parts, if, 

within 90 days from date of shipment, they have been proven to be defective in workmanship 

or material at the time of shipment. No allowance will be made for repairs or replacements 

made by others without written authorization from Magnetics.
Under no conditions shall Magnetics have any liability whatever for the loss of anticipated 

profits, interruption of operations, or for special, incidental or consequential damages.

24

Ta

pe

 W

oun

d Cores

48 Alloy

Orthonol

M

ag

ne

sil

Sup

erm

allo

y

 Pe

rm

allo

y 8

0

Bob

bin C

ores

Headquarters

110 Delta Drive

P .O . Box 11422 

Pittsburgh, PA 15238 • USA

Phone: 

1.800.245.3984

+1.412.696.1333

e-mail: 

magnetics@spang.com

www.mag-inc.com

 

Magnetics International

13/F 1-3 Chatham Road South

Tsim Sha Tsui

Kowloon, Hong Kong

Phone: 

+852.3102.9337

+86.139.1147.1417

e-mail: 

asiasales@spang.com

www.mag-inc.com.cn

©2016 Magnetics