RETMA Values

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Thanks to Nate, we need to point out that the RETMA value series are also known as the IEC 60063 standard value series. See here:

http://en.wikipedia.org/wiki/Preferred_numbers

In 1957 the Radio Electron Television Manufacturing Association established several series of standard values for components such as resistors, capacitors and inductors, depending on their tolerance. RETMA is no longer around, but the "RETMA values" are used in electronics to this day. JEDEC (the Joint Electron Device Engineering Council), a part of the Electronic Industries Alliance (EIA) has a nice web page that will bring you up to date on the history of electronic standards.

RETMA values exist for 20%, 10%, 5%, 1% and 0.1% tolerance. At microwave frequencies, you usually will not find inductors and capacitors at better than 10% tolerance, and resistors at 1%. The sequences are repeated at each decade, so that 10% inductors come in values of 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82, 100, 120, 150 nanohenries etc.

We found the following RETMA tables on a web site that no longer exists, so buyer, beware!

The 20% RETMA values:

100, 150, 220, 330, 470, 680

The 10% RETMA values:

100, 120, 150, 180, 220, 270, 330, 390, 470, 560, 680, 820

The 5% RETMA values:

100, 110, 120, 130, 150, 160, 180, 200, 220, 240, 270, 300, 330, 360, 390, 430, 470, 510, 560, 620, 680, 750, 820, 910

The 1% RETMA values:

100, 102, 105, 107, 110, 113, 115, 118, 121, 124, 127, 130, 133, 137, 140, 143, 147, 150, 154, 158, 162, 165, 169, 174, 178, 182, 187, 191, 196, 200, 205, 210, 215, 221, 226, 232, 237, 243, 249, 255, 261, 267, 274, 280, 287, 294, 301, 309, 316, 324, 332, 340, 348, 357, 365, 374, 383, 392, 402, 412, 422, 432, 442, 453, 464, 475, 487, 499, 511, 523, 536, 549, 562, 576, 590, 604, 619, 634, 649, 665, 681, 698, 715, 732, 750, 768, 787, 806, 825, 845, 866, 887, 909, 931, 953, 976

The 0.1% RETMA values:

100, 101, 102, 104, 105, 106, 107, 109, 110, 111, 113, 114, 115, 117, 118, 120, 121, 123, 124, 126, 127, 129, 130, 132, 133, 135, 137, 138, 140, 142, 143, 145, 147, 149, 150, 152, 154, 156, 158, 160, 162, 164, 165, 167, 169, 172, 174, 176, 178, 180, 182, 184, 187, 189, 191, 193, 196, 198, 200, 203, 205, 208, 210, 213, 215, 218, 221, 223, 226, 229, 232, 234, 237, 240, 243, 246, 249, 252, 255, 258, 261, 264, 267, 271, 274, 277, 280, 284, 287, 291, 294, 298, 301, 305, 309, 312, 316, 320, 324, 328, 332, 336, 340, 344, 348, 352, 357, 361, 365, 370, 374, 379, 383, 388, 392, 397, 402, 407, 412, 417, 422, 427, 432, 437, 442, 448, 453, 459, 464, 470, 475, 481, 487, 493, 499, 505, 511, 517, 523, 530, 536, 542, 549, 556, 562, 569, 576, 583, 590, 597, 604, 612, 619, 626, 634, 642, 649, 657, 665, 673, 681, 690, 698, 706, 715, 723, 732, 741, 750, 759, 768, 777, 787, 796, 806, 816, 825, 835, 845, 856, 866, 876, 887, 898, 909, 920, 931, 942, 953, 965, 976, 988