POWDER CORES

Molypermalloy  |   High Flux   |   Kool Mµ

®

   |   XF

lux

®

   |   Kool Mµ

® 

MAX

We offer the confidence of over sixty years of expertise in the 
research, design, manufacture and support of high quality magnetic 
materials and components. 

A major manufacturer of the highest performance materials in the 
industry including: MPP, High Flux, Kool Mµ®, Kool Mµ® MAX, 
XFlux®, 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 is the best choice for a variety 
of applications ranging from simple chokes and transformers used 
in telecommunications equipment to sophisticated devices for 
aerospace electronics. 

Magnetics backs it products with unsurpassed technical expertise 
and customer service. 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. 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.

www.mag-inc.com

1

Contents

Contents

Core Locator by Part Number

Core Index and Unit Pack Quantities  .  .  .  .  .  .  . 2

General Information

Introduction  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 8
Applications and Materials    .  .  .  .  .  .  .  .  .  .  .  .  .  . 9
Material Properties    .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 10
Core Weights and Unit Conversions   .  .  .  .  .  . 11
Core Identification   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 12
Inductance and Grading   .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 13
Core Coating    .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 14

Core Selection

Inductor Core Selection Procedure   .  .  .  .  .  .  . 15
Core Selection Example    .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 16
Toroid Winding    .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 17
Powder Core Loss Calculation    .  .  .  .  .  .  .  .  .  . 18
Core Selector Charts    .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 23
Wire Table   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 28

Material Data

Permeability versus DC Bias Curves   .  .  .  .  .  . 29
Core Loss Density Curves  .  .  .  .  .  .  .  .  .  .  .  .  .  . 35
DC Magnetization Curves   .  .  .  .  .  .  .  .  .  .  .  .  .  . 47
Permeability versus Temperature Curves   .  .  . 51
Permeability versus Frequency Curves    .  .  .  . 55

Core Data

Toroid Data   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 58
E Core Data    .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 96
Block Data    .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 97
U Core Data   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 98
MPP THINZ

®

 Data  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 99

Hardware

E Core Hardware    .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 100
Toroid Hardware   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 101

Winding Tables

Winding Tables   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 103 

Index

< Click the page name 

or page number to go 
directly to the page

MAGNETICS

2

Core Locator & Unit Pack Quantity

 55014 

61 

10,000

 55015 

61 

10,000

 55016 

61 

10,000

 55017 

61 

10,000

 55018 

61 

10,000

 55019 

61 

10,000

 55020 

61 

10,000

 55021 

61 

10,000

 55022 

61 

10,000

 55023 

61 

10,000

 55024 

65 

10,000

 55025 

65 

10,000

 55026 

65 

10,000

 55027 

65 

10,000

 55028 

65 

10,000

 55029 

65 

10,000

 55030 

65 

10,000

 55031 

65 

10,000

 55032 

65 

10,000

 55033 

65 

10,000

 55034 

68 

8,000

 55035 

68 

8,000

 55036 

68 

8,000

 55037 

68 

8,000

 55038 

68 

8,000

 55039 

68 

8,000

 55040 

68 

8,000

 55041 

68 

8,000

 55042 

68 

8,000

 55043 

68 

8,000

 55044 

70 

5,000

 55045 

70 

5,000

 55046 

70 

5,000

 55047 

70 

5,000

 55048 

70 

5,000

 55049 

70 

5,000

 55050 

70 

5,000

 55051 

70 

5,000

 55052 

70 

5,000

 55053 

70 

5,000

 55059 

74 

1,000

 55070 

88 

35

 55071 

77 

250

 55072 

88 

35

 55074 

88 

35

 55075 

88 

35

 55076 

79 

220

 55082 

81 

120

 55083 

80 

180

 55084 

81 

120

 55086 

81 

120

 55087 

81 

120

 55088 

81 

120

 55089 

81 

120

 55090 

81 

120

 55091 

81 

120

 55092 

81 

120

 55098 

93 

25

 55099 

93 

25

 55101 

93 

25

 55102 

93 

25

 55103 

85 

90

 55104 

85 

90

 55106 

85 

90

 55107 

85 

90

 55108 

85 

90

 55109 

85 

90

 55110 

85 

90

 55111 

85 

90

 55112 

85 

90

 55114 

71 

2,000

 55115 

71 

2,000

 55116 

71 

2,000

 55117 

71 

2,000

 55118 

71 

2,000

 55119 

71 

2,000

 55120 

71 

2,000

 55121 

71 

2,000

 55122 

71 

2,000

 55123 

71 

2,000

 55124 

69 

6,000

 55125 

69 

6,000

 55127 

69 

6,000

 55128 

69 

6,000

 55129 

69 

6,000

 55130 

69 

6,000

 55131 

69 

6,000

 55132 

69 

6,000

 55133 

69 

6,000

 55134 

58 

7,500

 55135 

58 

7,500

 55137 

58 

7,500

 55138 

58 

7,500

 55139 

58 

7,500

 55140 

58 

7,500

 55144 

59 

7,500

 55145 

59 

7,500

 55147 

59 

7,500

 55148 

59 

7,500

 55149 

59 

7,500

 55150 

59 

7,500

 55164 

95 

6

 55165 

95 

6

 55167 

95 

6

 55174 

60 

5,000

 55175 

60 

5,000

 55177 

60 

5,000

 55178 

60 

5,000

 55179 

60 

5,000

 55180 

60 

5,000

 55181 

60 

5,000

 55190 

86 

80

 55191 

86 

80

 55192 

86 

80

 55195 

86 

80

 55196 

86 

80

 55197 

86 

80

 55198 

86 

80

 55199 

86 

80

 55200 

73 

1,600

 55201 

73 

1,600

 55202 

73 

1,600

 55203 

73 

1,600

 55204 

73 

1,600

 55205 

73 

1,600

 55206 

73 

1,600

 55208 

73 

1,600

 55209 

73 

1,600

 55234 

62 

10,000

 55235 

62 

10,000 

 55236 

62 

10,000

 55237 

62 

10,000

 55238 

62 

10,000

 55239 

62 

10,000

 55240 

62 

10,000

 55241 

62 

10,000

 55242 

62 

10,000

 55243 

62 

10,000

 55248 

80 

180

 55249 

80 

180

 55250 

80 

180

 55251 

80 

180

 55252 

80 

180

 55253 

80 

180

 55254 

80 

180

 55256 

80 

180

 55257 

80 

180

 55264 

63 

10,000

 55265 

63 

10,000

 55266 

63 

10,000

 55267 

63 

10,000

 55268 

63 

10,000

 55269 

63 

10,000

 55270 

63 

10,000

 55271 

63 

10,000

 55272 

63 

10,000

 55273 

63 

10,000

 55274 

66 

8,000

 55275 

66 

8,000

 55276 

66 

8,000 

 55277 

66 

8,000

 55278 

66 

8,000

 55279 

66 

8,000

 55280 

66 

8,000

 55281 

66 

8,000

 55282 

66 

8,000

 55283 

66 

8,000

 55284 

67 

8,000

 55285 

67 

8,000

 55286 

67 

8,000

 55287 

67 

8,000

 55288 

67 

8,000

 55289 

67 

8,000

 55290 

67 

8,000

 55291 

67 

8,000

 55292 

67 

8,000

 55293 

67 

8,000

 55304 

74 

1,000

 55305 

74 

1,000

 55306 

74 

1,000

 55307 

74 

1,000

 55308 

74 

1,000

 55309 

74 

1,000

 55310 

74 

1,000

 55312 

74 

1,000

 55313 

74 

1,000

 55318 

79 

220

 55319 

79 

220

 55320 

79 

220

 55321 

79 

220

 55322 

79 

220

 55323 

79 

220

 55324 

79 

220

 55326 

79 

220

 55327 

79 

220

 55336 

94 

16

 55337 

94 

16

 55339 

94 

16

 55340 

94 

16

 55341 

94 

16

 55344 

75 

720

 55345 

75 

720

 55347 

75 

720

 55348 

75 

720

 55349 

75 

720

 55350 

75 

720

 55351 

75 

720

 55352 

75 

720

  55353 

75 

720     

 55374 

72 

2,000

 55375 

72 

2,000

 55377 

72 

2,000

 55378 

72 

2,000

 55379 

72 

2,000

 55380 

72 

2,000

 55381 

72 

2,000

 55382 

72 

2,000

 55383 

72 

2,000

 55404 

64 

10,000

 55405 

64 

10,000

 55407 

64 

10,000

 55408 

64 

10,000

 55409 

64 

10,000

 55410 

64 

10,000

 55411 

64 

10,000

 55412 

64 

10,000

 55413 

64 

10,000

 55432 

82 

105

 55433 

82 

105

 55435 

82 

105

 55436 

82 

105

 55437 

82 

105

 55438 

82 

105

 55439 

82 

105

 55440 

82 

105

 55441 

82 

105

 55542 

77 

250

 55543 

77 

250

 55544 

77 

250

 55545 

77 

250

 55546 

77 

250

 55547 

77 

250

 55548 

77 

250

 55550 

77 

250

 55551 

77 

250

 55579 

78 

300

 55580 

78 

300

 55581 

78 

300

 55582 

78 

300

 55583 

78 

300

 55584 

78 

300

 55585 

78 

300

 55586 

78 

300

 55587 

78 

300

 55588 

78 

300

 55614 

87 

45

 55615 

87 

45

 55617 

87 

45

 55620 

87 

45

 55709 

84 

90

 55710 

84 

90

 55712 

84 

90

 55713 

84 

90

 55714 

84 

90

 55715 

84 

90

 55716 

84 

90

 55717 

84 

90

 55718 

84 

90

 

55725 83 

70 

 55726 

83 

70

 55727 

83 

70 

 55728 

83 

70 

 55734 

89 

24

 55735 

89 

24

 55737 

89 

24

 55740 

89 

24

 55774 

92 

20

 55775 

92 

20

 55777 

92 

20

 55778 

92 

20

 55848 

73 

1,600

 55866 

90 

45

 55867 

90 

45

 55868 

90 

45

 55869 

90 

45

 55894 

76 

400

 55906 

91 

40

 55907 

91 

40

 55908 

91 

40

 55909 

91 

40

 55924 

76 

400

  55925 

76 

400

 55926 

76 

400

 55927 

76 

400

 55928 

76 

400

 55929 

76 

400

 55930 

76 

400

 55932 

76 

400

 55933 

76 

400

MPP Toroids

Index

P/N    PAGE  BOX QTY

P/N    PAGE  BOX QTY P/N    PAGE  BOX QTY

P/N    PAGE  BOX QTY

P/N    PAGE  BOX QTY

www.mag-inc.com

3

Core Locator & Unit Pack Quantity

High Flux Toroids

Index

P/N  PAGE  BOX QTY

P/N  PAGE  BOX QTY

P/N  PAGE  BOX QTY

P/N  PAGE  BOX QTY

 58018 

61 

10,000

 58019 

61 

10,000

 58020 

61 

10,000

 58021 

61 

10,000

 58022 

61 

10,000

 58023 

61 

10,000

   58028 

65 

10,000

 58029 

65 

10,000

 58030 

65 

10,000

 58031 

65 

10,000

 58032 

65 

10,000

 58033 

65 

10,000

 58038 

68 

8,000

 58039 

68 

8,000

 58040 

68 

8,000

 58041 

68 

8,000

 58042 

68 

8,000

 58043 

68 

8,000

 58048 

70 

5,000

 58049 

70 

5,000

 58050 

70 

5,000

 58051 

70 

5,000

 58052 

70 

5,000

 58053 

70 

5,000

 58059 

74 

1,000

 

58070 88 

35

 58071 

77 

250

 58072 

88 

35

 58073 

88 

35

 58074 

88 

35

 58075 

88 

35

 58076 

79 

220

 58083 

80 

180

 58089 

81 

120

 58090 

81 

120

 58091 

81 

120

 58092 

81 

120

 58099 

93 

25

 58100 

93 

25

 58101 

93 

25

 58102 

93 

25

 58109 

85 

90

 58110 

85 

90

 58111 

85 

90

 58112 

85 

90

 58118 

71 

2,000

 58119 

71 

2,000

 58120 

71 

2,000

 58121 

71 

2,000

 58122 

71 

2,000

 58123 

71 

2,000

 58128 

69 

6,000

 58129 

69 

6,000

 58130 

69 

6,000

 58131 

69 

6,000

 58132 

69 

6,000

 58133 

69 

6,000

 58164 

95 

6

 58165 

95 

6

 58190 

86 

80

 58191 

86 

80

 58192 

86 

80

 58195 

86 

80

 58204 

73 

1,600

 58205 

73 

1,600

 58206 

73 

1,600

 58208 

73 

1,600

 58209 

73 

1,600

 58238 

62 

10,000

 58239 

62 

10,000

 58240 

62 

10,000

 58241 

62 

10,000

 58242 

62 

10,000

 58243 

62 

10,000

 58252 

80 

180

 58253 

80 

180

 58254 

80 

180

 58256 

80 

180

 58257 

80 

180

 58268 

63 

10,000

 58269 

63 

10,000

 58270 

63 

10,000

 58271 

63 

10,000

 58272 

63 

10,000

 58273 

63 

10,000

 58278 

66 

8,000

 58279 

66 

8,000

 58280 

66 

8,000

 58281 

66 

8,000

 58282 

66 

8,000

 58283 

66 

8,000

 58288 

67 

8,000

 58289 

67 

8,000

 58290 

67 

8,000

 58291 

67 

8,000

 58292 

67 

8,000

 58293 

67 

8,000

 58308 

74 

1,000

   58309 

74 

1,000

 58310 

74 

1,000

 58312 

74 

1,000

 58313 

74 

1,000

 58322 

79 

220

 58323 

79 

220

 58324 

79 

220

 58326 

79 

220

 58327 

79 

220

 58336 

94 

16

 58337 

94 

16

 58338 

94 

16

 58339 

94 

16

 58348 

75 

720

 58349 

75 

720

 58350 

75 

720

 58351 

75 

720

 58352 

75 

720

 58353 

75 

720

 58378 

72 

2,000

 58379 

72 

2,000

 58380 

72 

2,000

 58381 

72 

2,000

 58382 

72 

2,000

 58383 

72 

2,000

 58408 

64 

10,000

 58409 

64 

10,000

 58410 

64 

10,000

 58411 

64 

10,000

 58412 

64 

10,000

 58413 

64 

10,000

 58437 

82 

105

 58438 

82 

105

 58439 

82 

105

 58440 

82 

105

 58441 

82 

105

 58546 

77 

250

 58547 

77 

250

 58548 

77 

250

 58550 

77 

250

 58551 

77 

250

 58583 

78 

300

 58584 

78 

300

 58585 

78 

300

 58586 

78 

300

 58587 

78 

300

 58588 

78 

300

 58614 

87 

45

 58615 

87 

45

 58616 

87 

45

 58617 

87 

45

 58620 

87 

45

 58714 

84 

90

 58715 

84 

90

 58716 

84 

90

 58717 

84 

90

 58718 

84 

90

 

58725 83 

70

 58726 

83 

70

 58727 

83 

70

 58728 

83 

70

 58734 

89 

24

 58735 

89 

24

 58736 

89 

24

 58737 

89 

24

 58774 

92 

20

 58775 

92 

20

 58776 

92 

20

 58777 

92 

20

 58778 

92 

20 

 58848 

73 

1,600

 58866 

90 

45

 58867 

90 

45

 58868 

90 

45

 58869 

90 

45

 58894 

76 

400

 58906 

91 

40

 58907 

91 

40

 58908 

91 

40

 58909 

91 

40

   58928 

76 

400

 58929 

76 

400

 58930 

76 

400

 58932 

76 

400

 58933 

76 

400

MAGNETICS

4

P/N  PAGE  BOX QTY

P/N  PAGE  BOX QTY

P/N  PAGE  BOX QTY

P/N  PAGE  BOX QTY

Core Locator & Unit Pack Quantity

Kool Mµ

®

 Toroids

 77020 

61 

10,000

 77021 

61 

10,000

 77030 

65 

10,000

 77031 

65 

10,000

 77040 

68 

8,000

 77041 

68 

8,000

 77050 

70 

5,000

 77051 

70 

5,000

 77052 

70 

5,000

 77054 

70 

5,000

 77055 

70 

5,000

 77059 

74 

1,000

 

77068 88 

35

 77069 

88 

35

 77070 

88 

35

 77071 

77 

250

 77072 

88 

35

 77073 

88 

35

 77074 

88 

35

 77075 

88 

35

 77076 

79 

220

 77083 

80 

180

 77089 

81 

120

 77090 

81 

120

 77091 

81 

120

 77093 

81 

120

 77094 

81 

120

 77095 

81 

120

 77098 

93 

25

 77099 

93 

25

 77100 

93 

25

 77101 

93 

25

 77102 

93 

25

 77109 

85 

90

 77110 

85 

90

 77111 

85 

90

 77120 

71 

2,000

 77121 

71 

2,000

 77130 

69 

6,000

 77131 

69 

6,000

 77140 

58 

7,500

 77141 

58 

7,500

 77150 

59 

7,500

 77151 

59 

7,500

 77154 

59 

7,500

 77155 

59 

7,500

 77164 

95 

6

 77165 

95 

6

 77180 

60 

5,000

 77181 

60 

5,000

 77184 

60 

5,000

 77185 

60 

5,000

 77189 

86 

80

 77191 

86 

80

 77192 

86 

80

 77193 

86 

80

 77194 

86 

80

 77195 

86 

80

 77206 

73 

1,600

 77210 

73 

1,600

 77211 

73 

1,600

 77212 

85 

90

 77213 

85 

90

 77214 

85 

90

 77224 

71 

2,000

 77225 

71 

2,000

 77240 

62 

10,000

 77241 

62 

10,000

 77244 

62 

10,000

 77245 

62 

10,000

 77254 

80 

180

 77256 

80 

180

 77258 

80 

180

 77259 

80 

180

 77260 

80 

180

 77270 

63 

10,000

 77271 

63 

10,000

 77280 

66 

8,000

 77281 

66 

8,000

 77290 

67 

8,000

 77291 

67 

8,000

 77294 

67 

8,000

 77295 

67 

8,000

 77310 

74 

1,000

 77312 

74 

1,000

 77314 

74 

1,000

 77315 

74 

1,000

 77316 

74 

1,000 

 77324 

79 

220

 77326 

79 

220

 77328 

79 

220

 77329 

79 

220

 77330 

79 

220 

 77334 

69 

6,000

 77335 

69 

6,000

 77336 

94 

16

    77337 

94 

16

 77338 

94 

16

 77339 

94 

16

 77350 

75 

720

 77351 

75 

720

 77352 

75 

720

 77354 

75 

720

 77355 

75 

720

 77356 

75 

720 

 77380 

72 

2,000

 77381 

72 

2,000

 77384 

72 

2,000

 77385 

72 

2,000

 77410 

64 

10,000

 77411 

64 

10,000

 77414 

64 

10,000

 77415 

64 

10,000

 77431 

82 

105

 77438 

82 

105

 77439 

82 

105

 77440 

82 

105

 77442 

82 

105

 77443 

82 

105

 77444 

58 

7,500

 77445 

58 

7,500

 77548 

77 

250

 77550 

77 

250

 77552 

77 

250

 77553 

77 

250

 77555 

77 

250

 77585 

78 

300

 77586 

78 

300

 77587 

78 

300

 77589 

78 

300

 77590 

78 

300

 77591 

78 

300

 77614 

87 

45

 77615 

87 

45

 77616 

87 

45

 77617 

87 

45

 77618 

87 

45

 77619 

87 

45

 77620 

87 

45

 77715 

84 

90

 77716 

84 

90

 77717 

84 

90

 77719 

84 

90

 77720 

84 

90

 77721 

84 

90

 77725 

83 

70

 77726 

83 

70

 77727 

83 

70

 77729 

83 

70

 77730 

83 

70

 77733 

83 

70

 77734 

89 

24

 77735 

89 

24

 77736 

89 

24

 77737 

89 

24

 77738 

89 

24

 77739 

89 

24

 77740 

89 

24

 77774 

92 

20

 77775 

92 

20

 77776 

92 

20

 77777 

92 

20

 77778 

92 

20

 77824 

61 

10,000

 77825 

61 

10,000

 77834 

65 

10,000

 77835 

65 

10,000

 77844 

68 

8,000

 77845 

68 

8,000

 77847 

73 

1,600 

    77848 

73 

1,600

 77866 

90 

45

 77867 

90 

45

 77868 

90 

45

 77869 

90 

45

 77872 

90 

45

 77874 

63 

10,000

 77875 

63 

10,000

 77884 

66 

8,000

 77885 

66 

8,000

 77894 

76 

400

 77906 

91 

40

 77907 

91 

40

 77908 

91 

40

 77909 

91 

40

 77912 

91 

40

 77930 

76 

400

 77932 

76 

400

 77934 

76 

400

 77935 

76 

400

  77936 

76    

400

Index

www.mag-inc.com

5

Core Locator & Unit Pack Quantity

 K114LE026 

96 

18

 K114LE040 

96 

18

 K114LE060 

96 

18

 K130LE026 

96 

12

 K130LE040 

96 

12

 K130LE060 

96 

12

 K160LE026 

96 

16

 K160LE040 

96 

16

 K160LE060 

96 

16

 K1808E026 

96 

2,880

 K1808E040 

96 

2,880

 K1808E060 

96 

2,880

 K1808E090 

96 

2,880

 K2510E026 

96 

1,728

 K2510E040 

96 

1,728

 K2510E060 

96 

1,728

 K2510E090 

96 

1,728

 K3007E026 

96 

720

 K3007E040 

96 

720

 K3007E060 

96 

720

 K3007E090 

96 

720

 K3112U040 

98 

672

 K3112U060 

98 

672

 K3112U090 

98 

672

 K3515E026 

96 

720

 K3515E040 

96 

720

 K3515E060 

96 

720

 K3515E090 

96 

720

 K4017E026 

96 

264

 K4017E040 

96 

264

 K4017E060 

96 

264

 K4017E090 

96 

264

 K4020E026 

96 

192

 K4020E040 

96 

192

 K4020E060 

96 

192

 K4020E090 

96 

192

 K4022E026 

96 

168

 K4022E040 

96 

168

 K4022E060 

96 

168

 K4022E090 

96 

168

 K4110U040 

98 

480

 K4110U060 

98 

480

 K4110U090 

98 

480

 K4111U040 

98 

480

 K4111U060 

98 

480

 K4111U090 

98 

480

 K4119U040 

98 

240

 K4119U060 

98 

240

 K4119U090 

98 

240

 K4317E026 

96 

270

 K4317E040 

96 

270

 K4317E060 

96 

270

 K4317E090 

96 

270

 K4741B026 

97 

48

 K4741B040 

97 

48

 K4741B060 

97 

48

 K5030B026 

97 

64

 K5030B040 

97 

64

 K5030B060 

97 

64

 K5527U026 

98 

128

 K5528B026 

97 

112

 K5528B040 

97 

112

 K5528B060 

97 

112

 K5528E026 

96 

112

 K5528E040 

96 

112

  K5528E060 

96  

112

 K5529U026 

98 

96

 K5530E026 

96 

96

 K5530E040 

96 

96

 K5530E060 

96 

96

 K6030B026 

97 

80

 K6030B040 

97 

80

 K6030B060 

97 

80

 K6527E026 

96 

54

 K6527E040 

96 

54

 K6527E060 

96 

54

 K6527U026 

98 

54

 K6533U026 

98 

54

 K7020B026 

97 

90

 K7020B040 

97 

90

 K7020B060 

97 

90

 K7030B026 

97 

60

 K7030B040 

97 

60

 K7030B060 

97 

60

 K7228E026 

96 

84

 K7228E040 

96 

84

 K7228E060 

96 

84

 K7236U026 

98 

60

 K8020E026 

96 

63

 K8020E040 

96 

63

 K8020E060 

96 

63

 K8020U026 

98 

63

 K8024E026 

96 

45

 K8024E040 

96 

45

 K8024E060 

96 

45

 K8030B026 

97 

48

 K8030B040 

97 

48

 K8030B060 

97 

48

 K8038U026 

98 

63

 K8044E026 

96 

63

 K8044E040 

96 

63

 K8044E060 

96 

63

 K9541B026 

97 

30

Kool Mµ

®

 Blocks, E Cores, and U Cores

P/N 

PAGE    BOX QTY

P/N 

PAGE    BOX QTY

P/N 

PAGE    BOX QTY

Index

MAGNETICS

6

Core Locator & Unit Pack Quantity

P/N 

PAGE    BOX QTY

P/N 

PAGE    BOX QTY

P/N 

PAGE    BOX QTY

 X114LE026 

96 

18

 X114LE040 

96 

18

 X114LE060 

96 

18

 X1808E026 

96 

2,880

 X1808E040 

96 

2,880

 X1808E060 

96 

2,880

 X3515E026 

96 

720

 X3515E040 

96 

720

 X3515E060 

96 

720

 X4017E026 

96 

264

 X4017E040 

96 

264

 X4017E060 

96 

264

 X4020E026 

96 

192

 X4020E040 

96 

192

 X4020E060 

96 

192

 X4022E026 

96 

168

 X4022E040 

96 

168

 X4022E060 

96 

168

 X4317E026 

96 

270

 X4317E040 

96 

270

 X4317E060 

96 

270

 X4741B026 

97 

48

 X4741B040 

97 

48

 X4741B060 

97 

48

 X5030B026 

97 

64

 X5030B040 

97 

64

 X5030B060 

97 

64

 X5528B026 

97 

112

 X5528B040 

97 

112

 X5528B060 

97 

112

 X5528E026 

96 

112

 X5528E040 

96 

112

 X5528E060 

96 

112

 X5530E026 

96 

96

 X5530E040 

96 

96

 X5530E060 

96 

96

 X6030B026 

97 

80

 X6030B040 

97 

80

 X6030B060 

97 

80

 X6527E026 

96 

54

 X6527E040 

96 

54

 X6527E060 

96 

54

 X7020B026 

97 

90

 X7020B040 

97 

90

 X7020B060 

97 

90

 X7030B026 

97 

60

 X7030B040 

97 

60

 X7030B060 

97 

60

 X7228E026 

96 

84

 X7228E040 

96 

84

 X7228E060 

96 

84

 X8020E026 

96 

63

 X8020E040 

96 

63

 X8020E060 

96 

63

 X8024E026 

96 

45

 X8024E040 

96 

45

 X8024E060 

96 

45

 X8030B026 

97 

48

 X8030B040 

97 

48

 X8030B060 

97 

48

 X8044E026 

96 

63

 X8044E040 

96 

63

 X8044E060 

96 

63

XF

lux

®

 Blocks and E Cores

XF

lux

®

 Toroids

Index

P/N  PAGE  BOX QTY

P/N  PAGE  BOX QTY

P/N  PAGE  BOX QTY

P/N  PAGE  BOX QTY

 78051 

70 

5,000

 78052 

70 

5,000

 78054 

70 

5,000

 78055 

70 

5,000

 78056 

70 

5,000

 78059 

74 

1,000

 78068 

88 

35

 78069 

88 

35

 78071 

77 

250

 78072 

88 

35

 78073 

88 

35

 78074 

88 

35

 78076 

79 

220

 78083 

80 

180

 78090 

81 

120

 78091 

81 

120

 78093 

81 

120

 78094 

81 

120

 78095 

81 

120

 78096 

93 

25

 78099 

93 

25

 78100 

93 

25

 78102 

93 

25

 78110 

85 

90

 78111 

85 

90

 78113 

71 

2,000

 78121 

71 

2,000

 78122 

71 

2,000

 78159 

93 

25

 78189 

86 

80

 78191 

86 

80

 78192 

86 

80

 78193 

86 

80

 78194 

86 

80

 78208 

73 

1,600

 78210 

73 

1,600

 78211 

73 

1,600

 78212 

85 

90

 78213 

85 

90

 78214 

85 

90

 78224 

71 

2,000

 78225 

71 

2,000

 78256 

80 

180

 78258 

80 

180

 78259 

80 

180

 78260 

80 

180

 78312 

74 

1,000

 78314 

74 

1,000

 78315 

74 

1,000

 78316 

74 

1,000

 78326 

79 

220

 78328 

79 

220

 78329 

79 

220

 78330 

79 

220

 78337 

94 

16

 78338 

94 

16

 78342 

94 

16

 78351 

75 

720

 78352 

75 

720

 78354 

75 

720

 78355 

75 

720

 78356 

75 

720

 78381 

72 

2,000

 78382 

72 

2,000

 78384 

72 

2,000

 78385 

72 

2,000

 78386 

72 

2,000

 78431 

82 

105

 78439 

82 

105

 78440 

82 

105

 78442 

82 

105

 78443 

82 

105

 78550 

77 

250

 78552 

77 

250

 78553 

77 

250

 78555 

77 

250

 78586 

78 

300

 78587 

78 

300

 78589 

78 

300

 78590 

78 

300

 78591 

78 

300

 78615 

87 

45

 78616 

87 

45

 78617 

87 

45

 78618 

87 

45

 78619 

87 

45

 78716 

84 

90

 78717 

84 

90

 78719 

84 

90

 78720 

84 

90

 78721 

84 

90

 78726 

83 

70

 78727 

83 

70

 78729 

83 

70

 78730 

83 

70

 78733 

83 

70

 78735 

89 

24

 78736 

89 

24

 78737 

89 

24

 78738 

89 

24

 78739 

89 

24

 

78775 92 

20

 78776 

92 

20

 78777 

92 

20

 

 78847 

73 

1,600

 78848 

73 

1,600

 78867 

90 

45

 78868 

90 

45

 78870 

90 

45

 78871 

90 

45

 78872 

90 

45

 78894 

76 

400

 78907 

91 

40

 78908 

91 

40

 78910 

91 

40

 78911 

91 

40

 78912 

91 

40

 78932 

76 

400

 78934 

76 

400

 78935 

76 

400

 78936 

76 

400

www.mag-inc.com

7

Core Locator & Unit Pack Quantity

 79051 

70 

5,000

 79052 

70 

5,000

 79059 

74 

1,000

 79071 

77 

250

 79072 

88 

35

 79074 

88 

35

 79076 

79 

220

 79083 

80 

180

 79090 

81 

120

 79091 

81 

120

 79099 

93 

25

 79102 

93 

25

 79110 

85 

90

 79111 

85 

90

 79121 

71 

2,000

 79122 

71 

2,000

 79191 

86 

80

 79192 

86 

80

 79208 

73 

1,600

 79256 

80 

180

 79312 

74 

1,000

 79326 

79 

220

 79337 

94 

16

 79351 

75 

720

 79352 

75 

720

 79381 

72 

2,000

 79382 

72 

2,000

 79439 

82 

105

 79440 

82 

105

 79550 

77 

250

 79586 

78 

300

 79587 

78 

300

 79615 

87 

45

 79617 

87 

45

 79716 

84 

90

 79717 

84 

90

 79726 

83 

70

 79727 

83 

70

 79735 

89 

24

 79737 

89 

24

 79848 

73 

1,600

 79867 

90 

45

 79868 

90 

45

 79894 

76 

400

 79907 

91 

40

 79908 

91 

40

 79932 

76 

400

 

Kool Mµ

®

 MAX Toroids

P/N 

PAGE    BOX QTY

P/N 

PAGE    BOX QTY

P/N 

PAGE    BOX QTY

Index

MAGNETICS

8

General Information

Introduction

Magnetics Molypermalloy Powder (MPP)

 cores are 

distributed air gap toroidal cores made from a 81% nickel, 
17% iron, and 2% molybdenum alloy powder for the lowest 
core losses of any powder core material .  MPP cores (and all 
powder cores) exhibit soft saturation, which is a significant 
design advantage compared with gapped ferrites .  Also, 
unlike ferrites, the MPP saturation curve does not need to 
be derated with increasing device temperature .

MPP cores possess many outstanding magnetic 
characteristics, such as high resistivity, low hysteresis and 
eddy current losses, excellent inductance stability after high 
DC magnetization or under high DC bias conditions and 
minimal inductance shift under high AC excitation .

MPP THINZ

®

, or washer cores, put the premium 

performance of Magnetics’ superior MPP material into 
robust, low height toroid form, for low profile inductors .  
With MPP THINZ, exact permeability and height are 
easily adjusted to result in the optimum design for each 
application .

Magnetics High Flux

 powder cores are distributed air 

gap toroidal cores made from a 50% nickel - 50% iron alloy 
powder for the highest biasing capability of any powder 
core material . High Flux cores have advantages that result 
in superior performance in certain applications involving high 
power, high DC bias, or high AC excitation amplitude .  The 
High Flux alloy has saturation flux density that is twice that 
of MPP alloy, and three times or more than that of ferrite .  As 
a consequence, High Flux cores can support significantly 
more DC bias current or AC flux density . 

High Flux offers much lower core losses and superior DC 
bias compared with powdered iron cores .  High Flux cores 
offer lower core losses and similar DC bias compared with 
XF

lux

 cores . Frequently, High Flux allows the designer to 

reduce the size of an inductive component compared with 
MPP, powdered iron, or ferrite .

  

Magnetics Kool Mµ

®

 powder cores are distributed air 

gap cores made from a ferrous alloy powder for low losses 
at elevated frequencies .  The near zero magnetostriction 
alloy makes Kool Mµ ideal for eliminating audible frequency 
noise in filter inductors .  In high frequency applications, core 
losses of powdered iron, for instance, can be a major factor 
in contributing to undesirable temperature rises .  Kool Mµ 
cores are superior because their losses are significantly 
less, resulting in lower temperature rises .  Kool Mµ cores 
generally offer a reduction in core size, or an improvement in 
efficiency, compared with powdered iron cores .

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 
inductors, and ease of fixturing . Very large cores and structures 
are available to support very high current applications .  These 
include toroids up to 102 mm, 133 mm and 165 mm; large E 
cores; U cores; stacked shapes; and blocks .

Magnetics Kool Mµ

®

 MAX

 powder cores are distributed 

air gap cores made from a ferrous alloy powder offering 
50% better DC bias performance than standard Kool Mµ 
material . Use of copper wire is minimized by maintaining 
inductance using less turns, resulting in savings in overall 
component cost . With its super low losses, Kool Mµ MAX 
does not mimic the same temperature rise problems found 
in iron powder cores . Inductors built with Kool Mµ MAX do 
not have several of the disadvantages that are inherent with 
gapped ferrite cores, including low saturation flux density 
and fringing losses at the discrete air gap .

Magnetics XF

lux

®

 distributed air gap cores are made from 

6 .5% silicon iron powder .  XF

lux

 offers lower losses than 

powdered iron cores and superior DC bias performance .  
The soft saturation of XF

lux

 material offers an advantage 

over ferrite cores .  XF

lux

 cores are ideal for low and medium 

frequency chokes where inductance at peak load is critical .

Magnetics Kool Mµ

®

, XF

lux

®

, MPP, High Flux 

and Kool Mµ

®

 MAX are true high temperature 

materials with no thermal aging.

Magnetics is committed to meeting global 
environmental standards and initiatives. Magnetics’ 
REACH and RoHS compliance statements and reports 
are available on our website: www.mag-inc.com

www.mag-inc.com

9

Applications and Materials

General Information

Magnetics powder cores are most commonly used in power 
inductor applications, specifically in switch-mode power 
supply (SMPS) filter inductors, also known as DC inductors 
or chokes .  Other power applications include differential 
inductors, boost inductors, buck inductors and flyback 
transformers .

While all five materials are used in these applications, each 
has its own advantages .  For the lowest loss inductor, 
MPP material should be used since it has the lowest core 
loss .  For the smallest package size in a DC bias dominated 
design, High Flux material should be used since it has the 
highest flux capacity .  XF

lux

®

 can be a lower cost alternative 

to High Flux, in situations where the higher core losses and 

more limited permeability availability of XF

lux

 is acceptable .

The unique advantages of Magnetics’ powder cores are 
used in a variety of other applications, including:  High Q 
filters, high reliability inductors and filters, high temperature 
inductors and filters, high current CTs, telecom filters, and 
load coils .

Magnetics’ powder cores are available in a variety of shapes 
including toroids, E cores, U cores, blocks, and cylinders, 
which can be used to create customizable structures . 

For 

more information on cylinders or custom shapes, please 
contact Magnetics.

A lower cost family of alternative products to Magnetics’ five premium powder core materials are powdered irons .  Manufacturers 
of powdered iron use a different production process .  For comparison with the above table, powdered irons have permeabilities 
from 10-100; highest core loss; good perm vs . DC bias; fair temperature stability; lower temperature ratings; soft saturation; 0% 
nickel content; lowest relative cost .

Kool Mµ and powdered iron cores have comparable DC bias performance . The advantages of Kool Mµ compared with powdered 
iron include (1) lower core losses; (2) no thermal aging, since Kool Mµ is manufactured without the use of organic binders; (3) near 
zero magnetostriction, which means that Kool Mµ can be useful for addressing audible noise problems; and (4) better stability of 
permeability vs . AC flux density .

Kool Mµ

®

XF

lux

®

Kool Mµ

® 

MAX

High Flux

MPP

Alloy Composition

FeSiAl

FeSi

FeSiAl

FeNi

FeNiMo

Available Permeabilities

14-125

26-90

26-60

14-160

14-550

Core Loss - 60µ (mW/cc)

50 kHz, 1000 G

214

590

205

333

174*

100 kHz, 1000 G

550

1,350

550

900

450*

Perm vs. DC Bias - 60µ (AT/cm)

80% of µ

i

34

76*

52

69

48

50% of µ

i

76

131*

103

131

84

60µ Temperature Stability - Typical % shift from -60 to 200°C

7%

5%

-

4%

2.5%

Curie Temperature

500°C

700°C

500°C

500°C

460°C

Saturation Flux Density (Tesla)

1.0

1.6

1.0

1.5

0.8

Frequency Response - 60µ flat to…

900 kHz

500 kHz

900 kHz

1 MHz

2MHz

Relative Cost

1*

1.2x

2x

4x-6x

7x-9x

*

indicates best choice

MAGNETICS

10

Material Data

Material Properties

PERMEABILITY vs. T, B, & f - TYPICAL

Permeability (µ)

µ vs. T dynamic range 

(-50º C TO +100º C)

MATERIALS RATED TO 200º C

µ vs. B dynamic range 

0 to 400 mT

µ vs. f. 

flat to...

MPP

14µ

0.7%

+0.4%

4 MHz

26µ

0.9%

+0.4%

3 MHz

60µ

1.0%

+0.8%

2 MHz

125µ

1.3% 

+1.4%

300 kHz

147µ, 160µ, 173µ

1.5%

+1.9%

200 kHz

200µ

1.6%

+2.8%

100 kHz

300µ

1.6%

+4.5%

90 kHz

550µ

8.7%

+21.0%

20 kHz

High Flux

14µ

1.5%

+5.0%

3 MHz

26µ

2.0%

+9.0%

1.5 MHz

60µ

2.6%

+13.5%

1 MHz

125µ

3.6%

+19.0%

700 kHz

147µ

4.8%

+22.0%

500 kHz

160µ

5.5%

+25.0%

400 kHz

Kool Mµ

®

26µ

1.7%

+1.0%

2 MHz

40µ

2.2%

+1.1%

1 MHz

60µ

3.4%

+1.4%

900 kHz

75µ

4.5%

+2.0%

500 kHz

90µ

5.2%

+2.8%

500 kHz

125µ

8.3%

+3.4%

300 kHz

X

F

lux

®

26µ

2.5%

- 

1 MHz

60µ

3.0%

+14.5%

500 kHz

Curie 

Temperature

Density

Coefficient of  

Thermal Expansion

MPP

460

°

C

8.0 grams/cm

3

12.9 x 10

-6

/

°

C

High Flux

500

°

C

7.6 grams/cm

3

5.8 x 10

-6

/

°

C

 Kool Mµ

500

°

C 

5.5 grams/cm

3

10.8 x 10

-6

/

°

C

X

F

lux

700

°

C

7.5 grams/cm

3

11.6 x 10

-6

/

°

C

www.mag-inc.com

11

Material Data

Core Weights

Unit Conversions

To obtain number of

Multiply number of

By

A.T/cm

oersteds

0.795

oersteds

A.T/cm

1.26

tesla

gauss

0.0001

gauss

tesla

10,000

gauss

mT(milli Tesla)

10

cm

2

in

2

6.452

cm

2

circular mils

(5.07)(10

-6

)

Permeability

14µ

26µ

40µ

60µ

75µ

90µ

125µ

147µ 

160µ 

173µ

200µ 

300µ

550µ

x Factor

0.80

0.86

0.90

0.94

0.96

0.97

1.00

1.02

1.03

1.04

Core weights listed in this catalog are for 125µ cores .*  
To determine weights for other permeabilities, multiply the 125µ weight by the following factors:

*XF

lux

®

 

and Kool Mµ

®

 MAX are based on 60µ weight .

*MPP, High Flux, and Kool Mµ

®

 in sizes 102, 337, and 165 weight based on 26µ .

MAGNETICS

12

General Information

Core Identification

All Magnetics powder cores have unique part numbers that provide important information about the characteristics of the cores . 
A description of each type of part number is provided below .

Core Finish Code

Voltage Breakdown 

(wire to wire)

Material Availability

OD Size Availability

A2

2,000 V

AC

 min

MPP, High Flux

All

A7

2,000 V

AC

 min

Kool Mµ, XF

lux

, Kool Mµ

 

MAX

All

AY

   600 V

AC

 min

All

3.56 - 16.5 mm

A5

2,000 V

AC

 min

All

6.35 - 23.6 mm

A9

8,000 V

AC

 min

All

>4.65 mm

TOROIDS
C O 5 5 2 0 6 A 2

SHAPES and THINZ
00K5528E060

LARGE E CORES
00K130LE026 

Catalog Number (designates size and permeability)
Material Code  . . . .  55 = MPP

 

58 = High Flux

 

77 = Kool Mµ

 

78 = XF

lux

 

79 = Kool Mµ MAX

Grading Code . . . . .  CO = Graded into 2% inductance bands  – OD <4.65 mm, 5% bands

 

00 = Not graded

  

• No voltage breakdown min for A2 or A7 with OD

 

^

4.65mm

• A2 and A7 voltage breakdown is 1000 V

AC  

with 4.65mm < OD < 26.9mm

• AY finish not available for 550µ MPP

Permeability Code ... Permeability, e.g. 060 for 60µ

Shape Code . . . . . .  E = E Core

 

T = Toroid

 

U = U Core

 

P = I Core/Plate

 

B = Block

Size Code . . . . . . .  First two digits equal approximate length 

 

or OD in mm / Last two digits equal 

 

approximate height or ID in mm

Material Code . . . . . K = Kool Mµ
 

M = MPP*

 

H = High Flux*

 

X = XF

lux

 

*consult factory

Grading Code . . . . .  00 = Not graded
 

• Full part number and shop order  

 

   number are marked on all shapes

Permeability Code . . Permeability, e.g. 026 for 26µ

Shape Code . . . . . .  LE = Large E Core

Size Code

Material Code . . . . . M = MPP*

 

H = High Flux* 

 

K = Kool Mµ

 

X = XF

lux

 

*consult factory 

Grading Code . . . . .  00 = Not graded

 

• Full part number and shop order  

 

   number are marked on all shapes

Size 

(OD mm)

6-digit  

Shop Order Number

2-digit  

Material Code

3-digit 

Catalog Number

2-digit 

Core Finish Code

Inductance  

Code

Marking  

Example

6.35 - 6.86

4

4

4

123456  020 +6

7.87 - 12.7

4

4

4

4

123456  050A2 +6

> 12.7

4

4

4

4

4

123456  55120A2 +6

Powder Core Toroid Marking Summary

•  Inductance Code is only marked on MPP and High Flux toroids with C0 grading code

•  Cores with OD < 6.35 mm are not marked

•  Shop order number identifies the product batch, ensuring traceability of every 

core through the entire manufacturing process, back to raw materials

www.mag-inc.com

13

Inductance and Grading

General Information

PARTS NOT GRADED

A

L

 (Inductance factor) is given for each core in this catalog . 

Inductance for blocks is tested in standard picture frame 
arrangements . Units for A

L

 are nH/T

2

 . A

L

 is related to nominal 

calculated inductance (L

N

, in µH) by the number of turns, N . 

L

N

 = A

L

 N

2

 10

-3

Magnetics’ inductance standards are measured in a Kelsall 
Permeameter Cup .  Actual wound inductance measured 
outside a Kelsall Cup is greater than the nominal calculated 
value due to leakage flux and flux developed by the current 
in the winding . The difference depends on many variables;  
core size, permeability, core coating thickness, wire size 
and number of turns, in addition to the way in which the 
windings are put on the core .  The difference is negligible 
for permeabilities above 125 and turns greater than 500 .  
However, the lower the permeability and/or number of turns, 
the more pronounced this deviation becomes .

The following formula can be used to approximate the leakage 
flux to add to the expected inductance .  This formula was 
developed from historical data of cores tested at Magnetics .  
Be aware that this will only give an approximation based on 
evenly spaced windings .  You may expect as much as a ±50% 
deviation from this result .

Example: C055930A2 with 25 turns (p . 76)

Example : C055930A2 (26 .9 mm, 125µ, p . 76)

Number  

of Turns

Calculated  

Inductance

Measured  

Inductance

1,000

157 mH

+0.0%

500

39.3 mH

+0.5%

300

14.1 mH

+1%

100

1.57 mH

+3%

50

393 µH

+5%

25

98.1 µH

+9%

Magnetics powder cores are precision manufactured to 
an inductance tolerance of ± 8%*, using standard Kelsall 
Permeameter Cup measurements with a precision series 
inductance bridge .

MPP and High Flux cores with outside diameters > 4 .65 mm 
are graded into 2% inductance bands as a standard practice 
at no additional charge .  Core grading can reduce winding 
costs by minimizing turns adjustments when building high 
turns inductors to very tight inductance specifications .  MPP 
cores 4 .65 mm and smaller are graded into 5% bands .

 • 14µ and 26µ cores • MPP THINZ

®

 • Parylene coated cores 

 
  The following toroid OD sizes: 
 

62 .0 mm OD 

68 .0 mm OD 

74 .1 mm OD 

 

77 .8 mm OD 

101 .6 mm OD 

132 .6 mm OD 

 

165 .1 mm OD

Core Inductance Tolerance and Grading

Measured vs. Calculated Inductance

+8

+8

+7

-4.0

-3.5

+6

+7

+5

-3.5

-2.5

+4

+5

+3

-2.5

-1.5

+2

+3

+1

-1.5

-0.5

+0

+1

-1

-0.5

+0.5

-2

-1

-3

+0.5

+1.5

-4

-3

-5

+1.5

+2.5

-6

-5

-7

+2.5

+3.5

-8

-7

-8

+3.5

+4.0

GRADE 

Stamped 

on Core 

OD

INDUCTANCE 

% Deviation 

from Nominal

From

From

To

To

TURNS 

% Deviation 

from Nominal

9 - old1 - 4?or5

L

LK

=

l

e

0 .292 N

1 .065

A

e

where:

L

LK

= leakage induc tan ce adder (µH)

N = number of turns
A

e

= core cross sec tion (mm

2

)

l

e

= core magnetic path length (mm)

Cata log Data

A

L

= 157 nH/T

2

A

e

= 65 .4 mm

2

I

e

= 63 .5 mm

Calculated Induc tan ce
L

N

= (157) (25)

2

10

-3

= 98 .1µH

Leakage Adder

L

LK

=

63 .5

0 .292 (25)

1 .065

(65 .4)

= 9 .3 µH

Est Measured Induc tan ce
L = L

N

+ L

LK

= 98 .1+ 9 .3
= 107 µH

Catalog Data

Calculated Inductance

 

 

Leakage Adder

Estimated Measured Inductance

9 - old1 - 4?or5

L

LK

=

l

e

0 .292 N

1 .065

A

e

where:

L

LK

= leakage induc tan ce adder (µH)

N = number of turns
A

e

= core cross sec tion (mm

2

)

l

e

= core magnetic path length (mm)

Cata log Data

A

L

= 157 nH/T

2

A

e

= 65 .4 mm

2

I

e

= 63 .5 mm

Calculated Induc tan ce
L

N

= (157) (25)

2

10

-3

= 98 .1µH

Leakage Adder

L

LK

=

63 .5

0 .292 (25)

1 .065

(65 .4)

= 9 .3 µH

Est Measured Induc tan ce
L = L

N

+ L

LK

= 98 .1+ 9 .3
= 107 µH

9 - old1 - 4?or5

L

LK

=

l

e

0 .292 N

1 .065

A

e

where:

L

LK

= leakage induc tan ce adder (µH)

N = number of turns
A

e

= core cross sec tion (mm

2

)

l

e

= core magnetic path length (mm)

Cata log Data

A

L

= 157 nH/T

2

A

e

= 65 .4 mm

2

I

e

= 63 .5 mm

Calculated Induc tan ce
L

N

= (157) (25)

2

10

-3

= 98 .1µH

Leakage Adder

L

LK

=

63 .5

0 .292 (25)

1 .065

(65 .4)

= 9 .3 µH

Est Measured Induc tan ce
L = L

N

+ L

LK

= 98 .1+ 9 .3
= 107 µH

9 - old1 - 4?or5

L

LK

=

l

e

0 .292 N

1 .065

A

e

where:

L

LK

= leakage induc tan ce adder (µH)

N = number of turns
A

e

= core cross sec tion (mm

2

)

l

e

= core magnetic path length (mm)

Cata log Data

A

L

= 157 nH/T

2

A

e

= 65 .4 mm

2

I

e

= 63 .5 mm

Calculated Induc tan ce
L

N

= (157) (25)

2

10

-3

= 98 .1µH

Leakage Adder

L

LK

=

63 .5

0 .292 (25)

1 .065

(65 .4)

= 9 .3 µH

Est Measured Induc tan ce
L = L

N

+ L

LK

= 98 .1+ 9 .3
= 107 µH

9 - old1 - 4?or5

L

LK

=

l

e

0 .292 N

1 .065

A

e

where:

L

LK

= leakage induc tan ce adder (µH)

N = number of turns
A

e

= core cross sec tion (mm

2

)

l

e

= core magnetic path length (mm)

Cata log Data

A

L

= 157 nH/T

2

A

e

= 65 .4 mm

2

I

e

= 63 .5 mm

Calculated Induc tan ce
L

N

= (157) (25)

2

10

-3

= 98 .1µH

Leakage Adder

L

LK

=

63 .5

0 .292 (25)

1 .065

(65 .4)

= 9 .3 µH

Est Measured Induc tan ce
L = L

N

+ L

LK

= 98 .1+ 9 .3
= 107 µH

L

LK

 = leakage inductance adder (µH)

N  = number of turns
A

e

  = core cross section (mm

2

)

I

e

  = core magnetic path length (mm)

Graded Magnetics MPP cores and High Flux cores are also available  
with tolerances tighter than the standard ± 8% .

*THINZ and Kool Mµ cores with OD < 12 .7 mm have wider tolerances .

MAGNETICS

14

Core Coating

General Information

Magnetics toroidal powder cores are coated with a special 
epoxy finish that provides a tough, wax tight, moisture 
and chemical resistant barrier having excellent dielectric 
properties . Toroids up to 16 .5 mm OD can also be parylene 
coated . Contact Magnetics for parylene-coated toroid 
requests .

The finish is tested for voltage breakdown by inserting a core 
between two weighted wire mesh pads . Force is adjusted 
to produce a uniform pressure of 10 psi, simulating winding 
pressure . The test condition for each core in the random 
sample set, to guarantee minimum breakdown voltage in each 
production batch, is 60 Hz rms voltage at 1 .25 the guaranteed 
limit . A2 and A7 samples (26 .9 mm and larger) are tested to 
2500 V min wire-to-wire . AY samples are tested to 750 V min 
wire-to-wire .

Material

Color

Core Finish Codes

MPP

Gray

A2, A5, A9

High Flux

Khaki

A2, A5, A9

Kool Mµ

®

 

Black

A7, A5, A9

XF

lux

®

Brown

A7, A5, A9

Kool Mµ

® 

MAX

Black

A7, A5, A9

Higher minimum breakdown coatings can be applied upon 
request for cores larger than 4 .65 mm .

Toroids as large as 16 .5 mm outside diameter can be 
coated with parylene to minimize the constriction of the 
inside diameter .  All finished dimensions in this catalog are 
for epoxy coating (A2 or A7) .  For a parylene coated toroid 
(AY), the maximum OD and HT are reduced by 0 .18 mm 
(0 .007”), and the minimum ID is increased by 0 .18 mm 
(0 .007”) .

The maximum steady-state operating temperature for epoxy 
coating is 200°C .  The maximum steady-state operating 
temperature for parylene coating is 130°C, but it can be 
used as high as 200°C for short periods, such as during 
board soldering . High temperature operation of Magnetics 
powder cores does not affect magnetic properties . 

MPP, High Flux, Kool Mµ, XF

lux

, 

and Kool Mµ MAX 

materials can be operated continuously at 200°C with no 
aging or damage .

NOTE: Special powder grades and 
processing were historically used with 
MPP for passive filter inductors. For 
information regarding D4, W4, M4 and L6 
codes, or precision inductor processing, 
contact Magnetics.

www.mag-inc.com

15

Cor
e Selection

Inductor Core Selection Procedure

Only two parameters of the design application must be 
known to select a core for a current-limited inductor;  in-
ductance required with DC bias and the DC current .  Use 
the following procedure to determine the core size and 
number of turns .

1 . 

 Compute the product of LI

2

 where:  

L = inductance required with DC bias (mH)  
I = DC current (A)

2 . 

 Locate the LI

2

 value on the Core Selector Chart 

(pgs . 24 - 27) .  Follow this coordinate to the inter-
section with the first core size that lies above the 
diagonal permeability line . This is the smallest core 
size that can be used .

3 . 

 The permeability line is sectioned into standard 
available core permeabilities .  Selecting the core 
listed on the graph will tend to be the best tradeoff 
between A

L

 and DC bias .

4 . 

 Inductance, core size, and permeability are now 
known .  Calculate the number of turns by using the 
following procedure:

 

(a)       The inductance factor (A

L

 in nH/T

2

) for the 

core is obtained from the core data sheet .  
Determine the minimum A

L 

by using the worst 

case negative tolerance (generally -8%) .  With 
this information, calculate the number of turns 
needed to obtain the required inductance 
from:

11old 2 - 1

N =

A

L

L 10

3

H =

l

e

NI

3

T (˚C) =

Component Surface Area (cm

2

)

Total Losses (mW)

U

Z

0 .833

 

       Where L is required inductance (µH)

 

(b)     Calculate the bias in A·T/cm from:

11old 2 - 1

N =

A

L

L 10

3

H =

l

e

NI

3

T (˚C) =

Component Surface Area (cm

2

)

Total Losses (mW)

U

Z

0 .833

 

(c)      From the Permeability vs . DC Bias curves 

(pgs . 29 - 33), determine the rolloff percentage 
of initial permeability for the previously calculat-
ed bias level .  Curve fit equations shown in the 
catalog can simplify this step . They are also 
available to use on Magnetics website: http://
www .mag-inc .com/design/design-guides/
Curve-Fit-Equation-Tool

 

(d)      Multiply the required inductance by the per-

centage rolloff to find the inductance with bias 
current applied .

 

 

(e)  Increase the number of turns by dividing the 

initial number of turns (from step 4(a)) by the 
percentage rolloff .  This will yield an inductance 
close to the required value after steps 4 (b), (c) 
and (d) are repeated .

 

(f)   Iterate steps 4 (b), (c) and (d) if needed to adjust 

turns up or down until the biased inductance is 
satisfactorily close to the target .

5 .   Choose a suitable wire size using the Wire Table (p . 

28) .  Duty cycles below 100% allow smaller wire 
sizes and lower winding factors, but do not allow 
smaller core sizes .

6 . 

 Design  Checks

 

(a) 

Winding Factor

 . See p .17 for notes on checking 

the coil design .

 (b) 

Copper Losses

 .

 

See p .17 for notes on calculat-

ing conductor resistance and losses .

 (c) 

Core Losses

 . See p .18 for notes on calculating 

AC core losses . If AC losses result in too much 
heating or low efficiency, then the inductor may 
be loss-limited rather than current-limited . Design 
alternatives for this case include using a larger 
core or a lower permeability core to reduce the 
AC flux density; or using a lower loss material 
such as MPP or Kool Mµ MAX in place of Kool 
Mµ, or High Flux in place of XF

lux

 .

 (d) 

Temperature Rise

 . Dissipation of the heat gener-

ated by conductor and core losses is influenced 
by many factors . This means there is no simple 
way to predict temperature rise (

%

T) precisely . 

But the following equation is known to give a 
useful approximation for a component in still air . 
Surface areas for cores wound to 40% fill are 
given with the core data in this catalog .

11old 2 - 1

N =

A

L

L 10

3

H =

l

e

NI

3

T (˚C) =

Component Surface Area (cm

2

)

Total Losses (mW)

U

Z

0 .833

0.00 mm O.D.

Cor

e Selection

MAGNETICS

16

Core Selection Example

Determine core size and number of turns to meet the 
following requirement:

(a)    Minimum inductance with DC bias of  

0 .6 mH (600 µH)

(b)   DC current of 5 .0 A

 
1 .     LI

2

= (0 .6)(5 .0)

2

=15 .0 mH·A

2

 
2 .      Using the Kool Mµ Toroids LI

2

 chart found on p . 

25, locate 15 mH·A

2

 on the bottom axis . Following 

this coordinate vertically results in the selection of 
0077083A7 as an appropriate core for the above 
requirements .

 
3 .      From the 0077083A7 core data p . 80, the inductance 

factor (A

L

) of this core is 81 nH/T

2

 ± 8% . The minimum 

A

L

 of this core is 74 .6 nH/T

2

 .  

 
4 .      The number of turns needed to obtain 600 µH at no 

load is 90 turns . To calculate the number of turns 
required at full load, determine the DC bias level:   
H= N·I/

l

e

 where 

l

e

 is the path length in cm . The DC bias 

is 45 .7 A·T/cm, yielding 71% of initial permeability from 
the 60µ Kool Mµ DC bias curve on p . 30 .The adjusted 
turns are 90/0 .71 =127 Turns .

5 .      Re-calculate the DC bias level . The permeability versus 

DC bias curve shows 57% of initial permeability at  
64 .5 A·T/cm .

 
6 .      Multiply the minimum A

L

 74 .6 nH/T

2

 by 0 .57 to yield 

effective A

L

 = 42 .5 nH/T

2

 . The inductance of this core 

with 127 turns and with 64 .5 A·T/cm will be 685 µH 
minimum . The inductance requirement has been met .

 
7 .      The wire table indicates that 17 AWG is needed to 

carry 5 .0 A with a current density of 500 A/cm

2

 .  

127 turns of 17 AWG (wire area = 1 .177 mm

2

) equals 

a total wire area of 149 .5 mm

2

 . The window area of a 

0077083A7 is 427 mm

2

 . Calculating window fill,  

149 .5 mm

2

/427 mm

2

 corresponds to an approximate 

35% winding factor . A 0077083A7 with 127 turns of  
17 AWG is a manufacturable design .

Cor

e Selection

0.00 mm O.D.

www.mag-inc.com

17

Cor
e Selection

4

Toroid Winding

Winding Factor

Winding factor, also called fill factor, is the ratio of total 

conductor cross section (usually copper cross section) to 

the area of the core window .  In other words, in a toroid, 

winding factor is given by: 

  

 

N

•

A

W

/W

A

  

N = Number of turns

     where: 

A

W 

= Area of the wire 

  

W

A 

= Window Area of the core 

p

 ·

ID

2

Toroid Core Winding factors can vary from 20-60%, a typical 

value in many applications being 35-40% .

In practice, several approaches to toroid winding are used:

- 

Single layer: The number of turns is limited by 

the inside circumference of the core divided by 

the wire diameter .  Advantages are lower winding 

capacitance, more repeatable parasitics, good 

cooling, and low cost .  Disadvantages are reduced 

power handling and higher flux leakage . 

- 

Low fill: For manufacturing ease and reduced 

capacitance, winding factor between single layer 

and 30% may be used . 

- 

Full winding: Factors between 30% and 45% 

are normally a reasonable trade off between fully 

utilizing the space available for a given core size, 

while avoiding excessive manufacturing cost . 

- 

High fill: Winding factors up to about 65% 

are achievable, but generally only with special 

expensive measures, such as completing each coil 

by hand after the residual hole becomes too small 

to fit the winding shuttle .

Estimating Wound Coil Dimensions

For each core size, wound coil dimensions are given for 

40% winding factor, since this is a typical, practical value .

Worst case package dimensions for coils wound completely 

full are also shown . These are max expected OD and max 

expected HT .

To estimate dimensions for other winding factors, use: 

 

Rv 7 - 17

OD

x%

=

40%

X% OD

40%

2

- OD

core

2

Q

V

+ OD

core

2

HT

x%

=ID

core

+ HT

core

-

60%

100%- X% ID

core

+ HT

core

- HT

40%

Q

V

2 - 8
H

ACmax

=

I

e

N I

DC

+ 2

3

I

S

X

#

&

2 - 9

H

ACmax

= 6 .35

20

20 + 2

2

S

X

= 66 .14

A

$

T

cm

"

B

ACmax

b

0 .44T

2 - 11

B

pk

= 0 .5 µ

0

Q V

%µ

i

Q V

µ

i

Q V

3

H

where

3

H

=

I

e

N

%

I

Where: X% is the new winding factor;

OD

40%

 and HT

40%

 are the coil dimensions shown on 

the core data page;

OD

core

 and HT

core

 are the maximum core dimensions 

after finish .

Cor
e Selection

MLT and DCR

MLT (Mean Length of Turn) is given for a range of winding 

factors for each core size . To estimate DCR, first, calculate 

the winding factor for the core, wire gauge, and number of 

turns selected .  On the wire table look up resistance per 

unit of length for the gauge selected . On the data page for 

the core selected, consult the Winding Turn Length chart .  

Unless the winding factor is exactly one of the values listed, 

interpolate to find the MLT . Then,

DCR = (MLT)(N) (

Q

/Length) .

For single layer winding, MLT is the 0% fill value on each 

core data page . Even easier, DCRs for single layer windings 

for a range of wire gauges are given in the winding tables on 

pgs . 103 - 107 .

Wire Loss

DC copper loss is calculated directly as I

2

R . Naturally, for 

aluminum conductors, a suitable wire table must be used . 

Also, the increase of wire resistance with temperature 

should be considered .

AC copper loss can be significant for large ripple and for 

high frequency . Unfortunately, calculation of AC copper loss 

is not a straight-forward matter . Estimates are typically used .

Cor

e Selection

MAGNETICS

18

Powder Core Loss Calculation

Magnetizing Force (A·T/cm)

60µ Kool Mµ DC Magnetization  (Example 2)

1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

10

100

Flux Density (T

esla)

160

147

125

90

75

60

40

26

14

173

200

250

300

550

500

550µ

160µ

H

AC min

H

AC max

B

AC max

B

AC min

B

H

 

Core loss is generated by the changing magnetic flux 

field within a material, since no magnetic materials exhibit 

perfectly efficient magnetic response .  Core loss density (PL) 

is a function of half of the AC flux swing (½  B=B

pk

) and 

frequency (

f

) . It can be approximated from core loss charts 

or the curve fit loss equation:

14 - old 2 - 8

PL = aB

pk

b

f

c

B

pk

= 2

%

B =

2

B

AC max

- B

AC min

H

AC max

=

I

e

N I

DC

+ 2

3

I

S

X

#

&

H

AC min

=

I

e

N I

DC

+ 2

3

I

S

X

#

&

where a, b, c are constants determined from curve fitting, 

and B

pk

 is defined as half of the AC flux swing:

14 - old 2 - 8

PL = aB

pk

b

f

c

B

pk

= 2

%

B =

2

B

AC max

- B

AC min

H

AC max

=

I

e

N I

DC

+ 2

3

I

S

X

#

&

H

AC min

=

I

e

N I

DC

+ 2

3

I

S

X

#

&

Units typically used are (mW/cm

3

) for PL; Tesla (T) for B

pk

; 

and (kHz) for 

f

 .

The task of core loss calculation is to determine B

pk

 from 

known design parameters . 

Example 1 - AC current is 10% of DC current:

Approximate the core loss of an inductor with 20 turns wound on Kool Mµ p/n 77894A7 p . 76 (60µ, 

l

e

=6 .35 cm, A

e

=0 .654 cm

2

, 

A

L

=75 nH/T

2

) . Inductor current is 20 Amps DC with ripple of 2 Amps peak-peak at 100kHz .

1 .) Calculate 

H

 and determine 

B

 from BH curve (p . 48) or curve fit equation (p . 50):

1415 - old 2 - 9 & 10

H

ACmax

= 6 .35

20

20 + 2

2

S

X

= 66 .14

A

$

T

cm

"

B

ACmax

b

0 .40T

H

ACmin

= 6 .35

20

20 - 2

2

S

X

= 59 .84

A

$

T

cm

"

B

ACmin

b

0 .37T

"

B

pk

= 2

%

B =

2

0 .40 - 0 .37 =0 .015T

PL = (62 .65) (0 .015

1 .781

)(100

1 .36

)

,

18 .5 cm

3

mW

P

fe

= (PL) (

l

e

) (A

e

) ~ (18 .5)(6 .35)(0 .654)

b

77mW

H

ACmax

= 6 .35

20

20 + 2

8

S

X

= 75 .59

A

$

T

cm

"

B

ACmax

b

0 .44T

H

ACmin

= 6 .35

20

20 - 2

8

S

X

= 50 .39

A

$

T

cm

"

B

ACmin

b

0 .33T

"

B

pk

= 2

%

B =

2

0 .44 - 0 .33 =0 .055T

PL = (62 .65) (0 .055

1 .781

) (100

1 .36

)

,

188 cm

3

mW

P

fe

= (PL) (

l

e

) (A

e

) = (188)(6 .35)(0 .654)

,

781mW

H

ACmax

= 6 .35

20

+ 2

8

S

X

= 12 .60

A

$

T

cm

"

B

ACmax

b

0 .092T

H

ACmin

= 6 .35

20

- 2

8

S X

= - 12 .60

A

$

T

cm

"

B

ACmin

b

-0 .092T

"

B

pk

= 2

%

B ~0 .092T

PL = (62 .65) (0 .092

1 .781

) (100

1 .36

)

,

470 cm

3

mW

P

fe

= (PL) (

l

e

) (A

e

) = (470)(6 .35)(0 .654)

,

1 .95W

     

1415 - old 2 - 9 & 10

H

ACmax

= 6 .35

20

20 + 2

2

S

X

= 66 .14

A

$

T

cm

"

B

ACmax

b

0 .40T

H

ACmin

= 6 .35

20

20 - 2

2

S

X

= 59 .84

A

$

T

cm

"

B

ACmin

b

0 .37T

"

B

pk

= 2

%

B =

2

0 .40 - 0 .37 =0 .015T

PL = (62 .65) (0 .015

1 .781

)(100

1 .36

)

,

18 .5 cm

3

mW

P

fe

= (PL) (

l

e

) (A

e

) ~ (18 .5)(6 .35)(0 .654)

b

77mW

H

ACmax

= 6 .35

20

20 + 2

8

S

X

= 75 .59

A

$

T

cm

"

B

ACmax

b

0 .44T

H

ACmin

= 6 .35

20

20 - 2

8

S

X

= 50 .39

A

$

T

cm

"

B

ACmin

b

0 .33T

"

B

pk

= 2

%

B =

2

0 .44 - 0 .33 =0 .055T

PL = (62 .65) (0 .055

1 .781

) (100

1 .36

)

,

188 cm

3

mW

P

fe

= (PL) (

l

e

) (A

e

) = (188)(6 .35)(0 .654)

,

781mW

H

ACmax

= 6 .35

20

+ 2

8

S

X

= 12 .60

A

$

T

cm

"

B

ACmax

b

0 .092T

H

ACmin

= 6 .35

20

- 2

8

S X

= - 12 .60

A

$

T

cm

"

B

ACmin

b

-0 .092T

"

B

pk

= 2

%

B ~0 .092T

PL = (62 .65) (0 .092

1 .781

) (100

1 .36

)

,

470 cm

3

mW

P

fe

= (PL) (

l

e

) (A

e

) = (470)(6 .35)(0 .654)

,

1 .95W

2 .) Determine Core Loss density from chart or calculate from loss equation p . 46:

1415 - old 2 - 9 & 10

H

ACmax

= 6 .35

20

20 + 2

2

S

X

= 66 .14

A

$

T

cm

"

B

ACmax

b

0 .40T

H

ACmin

= 6 .35

20

20 - 2

2

S

X

= 59 .84

A

$

T

cm

"

B

ACmin

b

0 .37T

"

B

pk

= 2

%

B =

2

0 .40 - 0 .37 =0 .015T

PL = (62 .65) (0 .015

1 .781

)(100

1 .36

)

,

18 .5 cm

3

mW

P

fe

= (PL) (

l

e

) (A

e

) ~ (18 .5)(6 .35)(0 .654)

b

77mW

H

ACmax

= 6 .35

20

20 + 2

8

S

X

= 75 .59

A

$

T

cm

"

B

ACmax

b

0 .44T

H

ACmin

= 6 .35

20

20 - 2

8

S

X

= 50 .39

A

$

T

cm

"

B

ACmin

b

0 .33T

"

B

pk

= 2

%

B =

2

0 .44 - 0 .33 =0 .055T

PL = (62 .65) (0 .055

1 .781

) (100

1 .36

)

,

188 cm

3

mW

P

fe

= (PL) (

l

e

) (A

e

) = (188)(6 .35)(0 .654)

,

781mW

H

ACmax

= 6 .35

20

+ 2

8

S

X

= 12 .60

A

$

T

cm

"

B

ACmax

b

0 .092T

H

ACmin

= 6 .35

20

- 2

8

S X

= - 12 .60

A

$

T

cm

"

B

ACmin

b

-0 .092T

"

B

pk

= 2

%

B ~0 .092T

PL = (62 .65) (0 .092

1 .781

) (100

1 .36

)

,

470 cm

3

mW

P

fe

= (PL) (

l

e

) (A

e

) = (470)(6 .35)(0 .654)

,

1 .95W

3 .) Calculate core loss:

1415 - old 2 - 9 & 10

H

ACmax

= 6 .35

20

20 + 2

2

S

X

= 66 .14

A

$

T

cm

"

B

ACmax

b

0 .40T

H

ACmin

= 6 .35

20

20 - 2

2

S

X

= 59 .84

A

$

T

cm

"

B

ACmin

b

0 .37T

"

B

pk

= 2

%

B =

2

0 .40 - 0 .37 =0 .015T

PL = (62 .65) (0 .015

1 .781

)(100

1 .36

)

,

18 .5 cm

3

mW

P

fe

= (PL) (

l

e

) (A

e

) ~ (18 .5)(6 .35)(0 .654)

b

77mW

H

ACmax

= 6 .35

20

20 + 2

8

S

X

= 75 .59

A

$

T

cm

"

B

ACmax

b

0 .44T

H

ACmin

= 6 .35

20

20 - 2

8

S

X

= 50 .39

A

$

T

cm

"

B

ACmin

b

0 .33T

"

B

pk

= 2

%

B =

2

0 .44 - 0 .33 =0 .055T

PL = (62 .65) (0 .055

1 .781

) (100

1 .36

)

,

188 cm

3

mW

P

fe

= (PL) (

l

e

) (A

e

) = (188)(6 .35)(0 .654)

,

781mW

H

ACmax

= 6 .35

20

+ 2

8

S

X

= 12 .60

A

$

T

cm

"

B

ACmax

b

0 .092T

H

ACmin

= 6 .35

20

- 2

8

S X

= - 12 .60

A

$

T

cm

"

B

ACmin

b

-0 .092T

"

B

pk

= 2

%

B ~0 .092T

PL = (62 .65) (0 .092

1 .781

) (100

1 .36

)

,

470 cm

3

mW

P

fe

= (PL) (

l

e

) (A

e

) = (470)(6 .35)(0 .654)

,

1 .95W

Method 1 – Determine B

pk

 from DC 

Magnetization Curve . B

pk

= 

f(

H

)

Flux density (B) is a non-linear function of magnetizing field (H), 

which in turn is a function of winding number of turns (N), current 

(I), and magnetic path length (

l

e

) . The value of B

pk

 can typically be 

determined by first calculating 

H

 at each AC extreme:

14 - old 2 - 8

PL = aB

pk

b

f

c

B

pk

= 2

%

B =

2

B

ACmax

- B

ACmin

H

ACmax

=

I

e

N I

DC

+ 2

3

I

S

X

#

&

H

ACmin

=

I

e

N I

DC

- 2

3

I

S

X

#

&

Units typically used are (A·T/cm) for H . 

From H

AC max

, H

AC min

, and the BH curve or equation (listed as 

DC Magnetization, pgs . 47 - 50) B

AC max

, B

AC min

 and therefore 

B

pk

 can be determined .