IEC 61605:2016

IEC 61605 ®
Edition 3.0 2016-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fixed inductors for use in electronic and telecommunication equipment –
Marking codes
Inductances fixes utilisées dans les équipements électroniques et de
télécommunications – Codes de marquage

IEC 61605 :2016-10(en-fr)
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IEC 61605 ®
Edition 3.0 2016-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fixed inductors for use in electronic and telecommunication equipment –

Marking codes
Inductances fixes utilisées dans les équipements électroniques et de

télécommunications – Codes de marquage

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.100.10 ISBN 978-2-8322-8775-0

– 2 – IEC 61605:2016 © IEC 2016
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Colour code for fixed inductors . 5
3.1 General rules . 5
3.2 Examples of colour code for fixed inductors . 6
4 Digit and letter code for inductance values . 7
4.1 General rules . 7
4.2 Examples of digit and letter code for inductance values . 8
5 Letter code for tolerances of inductance values . 9
5.1 Symmetrical tolerances . 9
5.2 Other tolerances . 9
6 Date code system for fixed inductors . 9
6.1 Single-character code for year and month . 9
6.2 Two-character code for year and month . 10
6.3 Four-character code for year and week . 11
Bibliography . 12

Figure 1 – Example for 47 μH ± 10 % . 6
Figure 2 – Example for 4,7 μH ± 2 % . 7
Figure 3 – Example for 4,7 nH ± 5 %. 7

Table 1 – Values corresponding to colours . 6
Table 2 – Cardinal numbers for the multiplier . 7
Table 3 – Examples of digit and letter code for inductance values . 8
Table 4 – Letter code for symmetrical tolerance . 9
Table 5 – Single-character code for year and month for a four-year cycle . 10
Table 6 – Code letter for year in a twenty-year cycle . 10
Table 7 – Character code letter for month . 11

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIXED INDUCTORS FOR USE IN ELECTRONIC AND
TELECOMMUNICATION EQUIPMENT – MARKING CODES

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61605 has been prepared by IEC technical committee 51: Magnetic
components and ferrite materials.
This third edition cancels and replaces the second edition published in 2005. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) The date code system for fixed inductors has been updated.
The text of this standard is based on the following documents:
CDV Report on voting
51/1135/CDV 51/1147/RVC
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 4 – IEC 61605:2016 © IEC 2016
The committee has decided that the contents of this publication will remain unchanged until the
stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to
the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
FIXED INDUCTORS FOR USE IN ELECTRONIC AND
TELECOMMUNICATION EQUIPMENT – MARKING CODES

1 Scope
This document specifies marking codes for fixed inductors.
The colour code specified in Clause 3 gives a colour coding for fixed inductors. It is intended for
use with the values of the E3 to E24 series as specified in IEC 60063.
The code specified in Clause 4 gives a system for marking inductance values by means of digits
and letters.
The code specified in Clause 5 gives a system for marking the tolerance on inductance values by
means of letters.
The code specified in Clause 6 gives a system for marking of date codes on fixed inductors by
means of letters and digits.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
ISO 8601, Data elements and interchange formats – Information interchange – Representation
of dates and times
3 Colour code for fixed inductors
3.1 General rules
Colour codes for fixed inductors should be expressed in “bands”. If other shapes than bands are
applied, the relevant specification shall prescribe their configuration, placement and
identification.
Colour codes for fixed inductors shall consist of four bands. The first three bands shall indicate
inductance values and the last band shall indicate tolerances.
Inductance values shall be expressed by two significant figures and another figure expressing
multipliers.
Colour corresponding to significant figures, multipliers and tolerances shall be as given in Table 1.
The first two bands represent significant figures and the third band specifies the multiplier. The
basic unit for the inductance value shall be expressed in µH. The first band shall be the one
nearest to the end of the inductor and the bands shall be so placed and spaced that there can be
no confusion in reading the coding.
Any additional coding on fixed inductors shall be applied in such a way as not to confuse the
coding for value and tolerance.

– 6 – IEC 61605:2016 © IEC 2016
Table 1 – Values corresponding to colours
Colour Significant figure Multiplier Tolerance
%
–2
Silver – 10 ± 10
–1
Gold – 10 ± 5
Black 0 10 –
Brown 1 10 ± 1
Red 2 10 ± 2
Orange 3 10 –
Yellow 4 10 –
Green 5 10 –
Blue 6 10 –
–3
Violet 7 10 –
–4
Grey 8 10 –
White 9 – –
None – – ± 20
3.2 Examples of colour code for fixed inductors
The examples of colour code for fixed inductors are shown in Figure 1, Figure 2 and Figure 3.
IEC
Key:
st st
1: 1 band 1 numeral Yellow = 4
nd nd
2: 2 band 2 numeral Violet = 7
rd 0
3: 3 band Multiplier Black = × 10
th
4: 4 band Tolerance Silver = ± 10 %
Figure 1 – Example for 47 μH ± 10 %

IEC
Key:
st st
1: 1 band 1 numeral Yellow = 4
nd nd
2: 2 band 2 numeral Violet = 7
rd -1
3: 3 band Multiplier Gold = × 10
th
4: 4 band Tolerance Red = ± 2 %
Figure 2 – Example for 4,7 μH ± 2 %
IEC
Key:
st st
1: 1 band 1 numeral Yellow = 4
nd nd
band 2 numeral Violet = 7
2: 2
rd -4
3: 3 band Multiplier Grey = × 10
th
4: 4 band Tolerance Gold = ± 5 %
Figure 3 – Example for 4,7 nH ± 5 %
4 Digit and letter code for inductance values
4.1 General rules
Nominal inductance values shall be expressed in three characters of letters and digits.
Where inductance values are equal to, or greater than, 10 µH, the first two characters indicate
significant figures and the last one indicates multipliers. In this case, cardinal numbers for the
multiplier shall be as given in Table 2.
Table 2 – Cardinal numbers for the multiplier
Cardinal number 0 1 2 3 4 5 6 7 8 9 –
0 1 2 3 4 5 6
Multiplier 10 10 10 10 10 10 10 – – – –

– 8 – IEC 61605:2016 © IEC 2016
Inductance values less than 10 µH and equal to, or greater than, 100 nH shall be identified with
two numbers representing the significant figures and the letter (R) designating decimal point
location µH, and the letter (N) designating decimal point location of nH for the inductance value
of less than 100 nH.
4.2 Examples of digit and letter code for inductance values
Examples of digit and letter code for inductance values are shown in Table 3.
Table 3 – Examples of digit and letter code for inductance values
Inductance values Digit and letter code
0,1 nH N10
0,47 nH N47
1 nH 1N0
4,7 nH 4N7
10 nH 10N
47 nH 47N
R10
0,1 µH
R47
0,47 µH
1R0
1 µH
4,7 µH 4R7
10 µH 100
47 µH 470
100 µH 101
470 µH
1 mH 102
4,7 mH 472
10 mH 103
47 mH 473
100 mH 104
470 mH 474
1 H 105
4,7 H 475
10 H 106
47 H 476
5 Letter code for tolerances of inductance values
5.1 Symmetrical tolerances
The letter codes shown in Table 4 shall be used to indicate the symmetrical tolerance on
inductance values.
Table 4 – Letter code for symmetrical tolerance
Tolerance Letter code
W
± 0,05 nH
± 0,1 nH B
± 0,2 nH C
± 0,3 nH S
± 0,5 nH D
± 1 % F
± 2 % G
H
± 3 %
± 5 % J
± 10 % K
L
± 15 %
± 20 % M
± 30 % N
These letter codes shall be placed after the inductance values.
5.2 Other tolerances
For tolerances for which a code letter has not been laid down, the letter A may be used. The
letter A indicates that the tolerance is to be identified in other documents.
6 Date code system for fixed inductors
6.1 Single-character code for year and month
Date codes of year and month in single-character shall be expressed in the code system shown
in Table 5 and should be repeated every four years.

– 10 – IEC 61605:2016 © IEC 2016
Table 5 – Single-character code for year and month for a four-year cycle
Year Month Letter Year Month Letter Year Month Letter Year Month Letter
2001 Jan. A 2002 Jan. N 2003 Jan. a 2004 Jan. n
2005 Feb. B 2006 Feb. P 2007 Feb. b 2008 Feb. p
2009 Mar. C 2010 Mar. Q 2011 Mar. c 2012 Mar. q
2013 Apr. D 2014 Apr. R 2015 Apr. d 2016 Apr. r
2017 May E 2018 May S 2019 May e 2020 May s
2021 Jun. F 2022 Jun. T 2023 Jun. f 2024 Jun. t
2025 Jul. G 2026 Jul. U 2027 Jul. g 2028 Jul. u
2029 Aug. H 2030 Aug. V 2031 Aug. h 2032 Aug. v
2033 Sep. J 2034 Sep. W 2035 Sep. j 2036 Sep. w
2037 Oct. K 2038 Oct. X 2039 Oct. k 2040 Oct. x
・ Nov. L ・ Nov. Y ・ Nov. l ・ Nov. y
・ Dec. M ・ Dec. Z ・ Dec. m ・ Dec. z
NOTE 1 Those codes which indicate the year and month with one capital letter and small letter, except “I” and “O”,
repeat after each cycle of four years.
NOTE 2 If there is a possibility that a single lower-case letter could be read
...