IEC 62674-1:2012

IEC 62674-1 ®
Edition 1.0 2012-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
High frequency inductive components –
Part 1: Fixed surface mount inductors for use in electronic and
telecommunication equipment
Composants inductifs à haute fréquence –
Partie 1: Inductances fixes pour montage en surface utilisées dans les matériels
électroniques et les équipements de télécommunications

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IEC 62674-1 ®
Edition 1.0 2012-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
High frequency inductive components –

Part 1: Fixed surface mount inductors for use in electronic and

telecommunication equipment
Composants inductifs à haute fréquence –

Partie 1: Inductances fixes pour montage en surface utilisées dans les matériels

électroniques et les équipements de télécommunications

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX V
ICS 29.100.10 ISBN 978-2-83220-399-6

– 2 – 62674-1  IEC:2012
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Designation . 7
5 Shape . 9
6 Dimensions . 10
6.1 Shape D . 10
6.2 Shape K . 11
6.3 Tolerance for outline dimensions . 11
7 Ratings and characteristics. 11
7.1 Nominal inductance or impedance . 11
7.2 Tolerance for nominal inductance or impedance . 12
7.3 Operating temperature range . 12
8 Marking . 13
9 Direction marking or shape of polarity. 13
10 Tests and performance requirements . 14
10.1 Standard atmospheric conditions for testing . 14
10.1.1 Standard atmospheric conditions for measurements and tests . 14
10.1.2 Referee condition . 14
10.2 Visual examination and check of dimensions . 14
10.2.1 Visual examination . 14
10.2.2 Dimensions. 14
10.3 Electrical performance tests . 15
10.3.1 Inductance . 15
10.3.2 Q . 18
10.3.3 Impedance . 22
10.3.4 Self-resonant frequency . 22
10.3.5 DC resistance . 24
10.3.6 Rated current . 25
10.4 Mechanical performance tests . 25
10.4.1 Mounting to substrate . 25
10.4.2 Body strength test . 25
10.4.3 Robustness of terminations (electrodes) . 25
10.4.4 Solderability . 26
10.4.5 Resistance to soldering heat. 26
10.4.6 Resistance to dissolution of metallization . 26
10.4.7 Vibration . 27
10.4.8 Resistance to shock . 27
10.5 Environmental and climatic tests . 27
10.5.1 Cold . 27
10.5.2 Dry heat . 28
10.5.3 Change of temperature . 29
10.5.4 Damp heat (steady state) . 29
10.5.5 Component solvent resistance . 30

62674-1  IEC:2012 – 3 –
Bibliography . 31

Figure 1 – Shapes of inductor and ferrite beads (examples) . 9
Figure 2 – Example of circuit for measurement by the bridge method . 15
Figure 3 – Example of circuit for measurement by the vector voltage/current method . 16
Figure 4 – Example of a circuit for measurement by the automatic balancing bridge
method . 17
Figure 5 – Example of circuit for measurement by the series resonance method . 19
Figure 6 – Example of a circuit for measurement by the parallel resonance method . 20
Figure 7 – Tuning characteristics of inductor . 20
Figure 8 – Example of circuit for measurement by the minimum output method . 23
Figure 9 – Example of measuring circuit for DC resistance . 24

Table 1 – Letter code for inductance value . 8
Table 2 – Dimensions for shape D . 10
Table 3 – Dimensions of height for shape D (R 20 series) . 10
Table 4 – Dimensions of height for shape D less than 1,00 mm . 10
Table 5 – Dimensions for shape K . 11
Table 6 – Tolerance for outline dimension and height . 11
Table 7 – E 24 series for nominal inductance or impedance . 12
Table 8 – Tolerance for nominal inductance or impedance . 12
Table 9 – Temperatures to be selected for operating temperature ranges . 12
Table 10 – User reference / Examples of application and operating temperature range . 13
Table 11 – Electrical performance . 26
Table 12 – Combined test conditions for cold . 28
Table 13 – Combined test conditions for dry heat. 28
Table 14 – Test conditions for change of temperature . 29
Table 15 – Test conditions for damp heat (steady state) . 30

– 4 – 62674-1  IEC:2012
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HIGH FREQUENCY INDUCTIVE COMPONENTS –

Part 1: Fixed surface mount inductors for use in electronic
and telecommunication equipment

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
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Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
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with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
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consensus of opinion on the relevant subjects since each technical committee has representation from all
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services carried out by independent certification bodies.
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 62674-1 has been prepared by IEC technical committee 51:
Magnetic components and ferrite materials.
The text of this standard is based on the following documents:
FDIS Report on voting
51/1006/FDIS 51/1009/RVD
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.

62674-1  IEC:2012 – 5 –
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.
– 6 – 62674-1  IEC:2012
HIGH FREQUENCY INDUCTIVE COMPONENTS –

Part 1: Fixed surface mount inductors for use in electronic
and telecommunication equipment

1 Scope
This part of IEC 62674 applies to fixed surface mount inductors and ferrite beads.
The object of this standard is to define the terms necessary to describe the inductors covered
by this standard, provide recommendations for preferred characteristics, recommended
performance, test methods and general guidance.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60068-1:1988, Environmental testing – Part 1: General and guidance
IEC 60068-2-1:2007, Environmental testing – Part 2-1: Tests – Test A: Cold
IEC 60068-2-2:2007, Environmental testing – Part 2-2: Tests – Test B: Dry heat
IEC 60068-2-14:2009, Environmental testing – Part 2-14: Tests – Test N: Change of
temperature
IEC 60068-2-45, Basic environmental testing procedures – Part 2-45: Tests – Test XA and
guidance: Immersion in cleaning solvents
IEC 60068-2-58:2004, Environmental testing – Part 2-58: Tests – Test Td: Test methods for
solderability, resistance to dissolution of metallization and to soldering heat of surface
mounting devices (SMD)
IEC 60068-2-78, Environmental testing – Part 2-78: Tests – Test Cab: Damp heat, steady
state
IEC 61605:2005, Fixed inductors for use in electronic and telecommunication equipment –
Marking codes
IEC 62024-1:2008, High frequency inductive components – Electrical characteristics and
measuring methods – Part 1: Nanohenry range chip inductor
IEC 62024-2:2008, High frequency inductive components – Electrical characteristics and
measuring methods – Part 2: Rated current of inductors for DC to DC converters
IEC 62025-2:2005, High frequency inductive components – Non-electrical characteristics and
measuring methods – Part 2: Test methods for non-electrical characteristics
IEC 62211:2003, Inductive components – Reliability management

62674-1  IEC:2012 – 7 –
ISO 3:1973, Preferred numbers – Series of preferred numbers
ISO 3599, Vernier callipers reading to 0,1 and 0,05 mm
ISO 3611, Geometrical product specifications (GPS) – Dimensional measuring equipment:
Micrometers for external measurements – Design and metrological characteristics
ISO 6906, Vernier callipers reading to 0,02 mm
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
rated current
maximum current which may be loaded continuously by inductors at the rated temperature
Note 1 to entry: A DC saturation limited current value or a temperature rise limited current value, whichever is
less, has been adopted as the rated current (see IEC 62024-2:2008, Clause 7).
3.2
operating temperature range
category temperature range
range of ambient temperatures for which the inductor has been designed to operate
continuously
Note 1 to entry: Unless otherwise specified in the detail specification, the operating temperature is ambient
temperature plus temperature rise of components.
4 Designation
It is recommended to express the designation of the fixed surface mount inductors by the
following 12 digits format. In the case of another format, designation shall be specified in the
detail specifications.
The designation of ferrite beads shall be specified in the detail specifications.
□□□ □□□□ □ □□□ □
a) b) c) d) e)
a) Identification of the type of inductor
Fixed surface mount inductors shall be identified by the three alphabetic characters ‘LCL’.
b) Indication of outline dimensions
The outline dimensions of the surface mount inductor shall be indicated by a four-digit
number based on two significant figures for each dimension of L and W (or H). As for the
dimensions of shape D, the first two digits indicate the longer side dimension L, and the
last two digits indicate the shorter side dimension W, as shown in Figure 1. As for the
dimensions of shape K, the first two digits indicate the outline dimension L, and the last
two digits indicate the height dimension H.
c) Indication of shape
A single alphabetic character as given in Figure 1 indicates the shape for fixed surface
mount inductors.
– 8 – 62674-1  IEC:2012
The shape codes are classified by the base shape of inductors.
D: rectangular
K: square
d) Indication of nominal inductance
Three alphanumeric characters specified in IEC 61605:2005, Clause 4, indicate the
nominal inductance value (see Table 1).
Table 1 – Letter code for inductance value
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
0,1   µH R10
R47
0,47  µH
1R0
1    µH
4R7
4,7   µH
10    µH
47    µH
100    µH
470    µH
1    mH
4,7   mH
10     mH
47     mH
100     mH
470     mH
1     H
4,7   H
10     H
47     H
e) Indication of tolerance for inductance
Single alphabetic characters specified in Table 8 indicate the tolerance for the inductance
value.
62674-1  IEC:2012 – 9 –
5 Shape
The shapes of fixed surface mount inductors and ferrite beads are classified as shown in
Figure 1.
H
H
H
L
L
L
W
W
W
H
L
W
IEC  1855/12
Shape D
H
H
L
L
L
L
L
H
H
L
L
L
Shape K
IEC  1856/12
Figure 1 – Shapes of inductor and ferrite beads (examples)

– 10 – 62674-1  IEC:2012
6 Dimensions
6.1 Shape D
For the dimensions for shape D, see a) and b).
a) Outline dimensions L (long side) and W (short side) of shape D shall be chosen from the
values marked with x in Table 2. These values have been selected from the R 20 series of
ISO 3:1973, but the values 0,315, 0,56 and 3,15 have been rounded off to 0,3, 0,6 and 3,2
respectively. 1,25 may be rounded off to 1,2.
b) Dimensions of height greater than 1,00 mm shall be chosen from Table 3. These values
are taken from the R 20 series of ISO 3:1973 where, however, the values 1,12, 2,24, 3,15
and 3,55 have been rounded off to 1,1, 1,2, 3,2 and 3,6 respectively. 1,25 may be rounded
off to 1,2. Dimensions of height, less than 1,00 mm, shall be selected from Table 4.
Table 2 – Dimensions for shape D
W
(short side)
L
mm
(long side)
mm 1,25
0,2 0,3 0,4 0,5 0,8 1,0 1,6 1,8 2,0 2,5 3,2 4,0 5,0 5,6 6,3 7,1
(1,2)
0,4 X
0,6 X
0,8  X
1,0  X
1,2   X
1,6   X X
2,0   X X X
2,5     X X
3,2    X X X
4,0
4,5    X  X X
5,0       X
5,6       X
6,3        X
7,1        X
8,0         X
Table 3 – Dimensions of height for shape D (R 20 series)
Dimensions in millimetres
1,25
1,0 1,1 1,4 1,6 1,8 2,0 2,2 2,5 2,8 3,2
(1,2)
3,6 4,0 4,5 5,0 5,6 6,3 7,1 8,0 9,0 10,0

Table 4 – Dimensions of height for shape D less than 1,00 mm
0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,85 0,9

62674-1  IEC:2012 – 11 –
6.2 Shape K
Outline dimensions L and H of shape K shall be chosen from the values marked with x in
Table 5.These values are based on the R 20 series of ISO 3:1973.
Table 5 – Dimensions for shape K
H
L
(height)
(length)
mm
mm
0,6 0,8 0,9 1,0 1,1 1,2 1,4 1,6 1,8 2,0 2,2 2,5 3,2 4,0 4,5 5,0 6,3 7,1 8,0 9,0
2,5 X X X   X
2,8 X X X X X
3,2  X X X X
3,6     X
4,0  X X X X X X X
4,5       X
5,0    X  X X  X X
5,6     X    X
6,3         X
7,1         X
8,0       X   X
9,0          X
10,0       X X
12,0        X
6.3 Tolerance for outline dimensions
Tolerance for outline dimension and height shall be selected from Table 6.
Table 6 – Tolerance for outline dimension and height
Tolerances
Outline dimensions (X)
mm
mm
Standard Maximum
× ≤ 0,6 ± 0,05  ± 0,10
0,6 < × ≤ 1,0 ± 0,10 ± 0,20
1,0 < × ≤ 1,6 ± 0,15 ± 0,30
1,6 < × ≤ 2,5 ± 0,20 ± 0,40
2,5 < × ≤ 4,0 ± 0,30 ± 0,60
4,0 < × ≤ 8,0 ± 0,40 ± 0,80
8,0 < × ≤ 10,0 ± 0,50 ± 1,00
7 Ratings and characteristics
7.1 Nominal inductance or impedance
The preferred values of nominal inductance or impedance shall be selected from the numeric
values of the E 24 series in Table 7 and their decimal multiples or submultiples.

– 12 – 62674-1  IEC:2012
The detail specification sheet should clearly note whether the value given is inductance or
impedance, as well as the units and measuring frequency. The choice of specifying either
inductance or impedance depends on the intended application for the inductor.
Table 7 – E 24 series for nominal inductance or impedance
1,0 1,1 1,2 1,3 1,5 1,6 1,8 2,0 2,2 2,4 2,7 3,0
3,3 3,6 3,9 4,3 4,7 5,1 5,6 6,2 6,8 7,5 8,2 9,1

7.2 Tolerance for nominal inductance or impedance
The tolerance for nominal inductance or impedance shall be selected from Table 8 which
includes the tolerances specified in IEC 61605:2005, 5.1.
Table 8 – Tolerance for nominal inductance or impedance
± 0,05 ± 0,1 ± 0,2 ± 0,3 ± 0,5 ± 1 ± 2 ± 3 ± 5 ± 10 ± 15 ± 20 ± 25 ± 30
Tolerance
nH nH nH nH nH % % % % % % % % %
Letter
W B C S D F G H J K L M - N
code
NOTE 1 nH should be applied to inductance only.
NOTE 2 ± 25 % should be applied to impedance only.

7.3 Operating temperature range
The operating temperature range shall be selected from a lower temperature and an upper
temperature in Table 9. Examples of the application and operating temperature range (user
reference) are shown in Table 10.
Table 9 – Temperatures to be selected for operating temperature ranges
Lower temperature Upper temperature
°C °C
– 55 + 155
– 40 + 150
– 25 + 125
– 10 + 105
+ 100
+ 85
+ 70
+ 40
NOTE Unless otherwise specified in the detail specification, the
operating temperature is the ambient temperature plus the
temperature rise of components.

62674-1  IEC:2012 – 13 –
Table 10 – User reference /
Examples of application and operating temperature range
Category applies Temperature range Standard identification
°C
Automobile and aerospace –55 to +155 MIL-PRF-27, Class V
–55 to +150 IEC 62211:2003, Level S
–55 to +125 -
–40 to +150 -
–40 to +125 AEC Q200,Grade 1
IEC 62211:2003,Level A
Telecommunication and power supply –55 to +105 MIL-PRF-27, Class R
–55 to +85 MIL-PRF-27, Class Q
–40 to +125 IEC 62211:2003, Level B
–40 to +105 AEC Q200, Grade 2
IEC 62211:2003, Level B
–40 to +85 AEC Q200, Grade 3
IEC 62211:2003, Level B
Consumer and commercial electronics –40 to +85
IEC 62211:2003, Level C
AEC Q200, Grade 3
–25 to +105 -
–25 to +100 -
–25 to +85 -
–25 to +70 IEC 62211:2003, Level D
0 to +70 AEC Q200, Grade 4
NOTE AEC Q200 and IEC 62211:2003 are component-level reliability specifications. A
distinction exists between component-level and system-level specifications.

8 Marking
The selection of type(s) of marking information is subject to agreement between supplier and
user. In lieu of such an agreement, the marking information should be as published in the
supplier’s data sheet. One or more of the following types of marking information is
recommended on the body or the packaging:
a) user part number;
b) serial number, lot code or date code;
c) characteristics as specified in IEC 61605:2005;
d) supplier part number and logo or mark;
e) quantity (packaging only).
9 Direction marking or shape of polarity
For the purpose of indicating the winding start location, or the first pin number, or first
electrode, or winding orientation, either a mark or a shape should be used. A shape inductor
is a corner cut, or small circle indent, or other molded feature, or terminal shape that indicates
polarity on the inductor (if such an indication is necessary).

– 14 – 62674-1  IEC:2012
10 Tests and performance requirements
10.1 Standard atmospheric conditions for testing
10.1.1 Standard atmospheric conditions for measurements and tests
Unless otherwise specified, all tests and measurements shall be made under standard
atmospheric conditions as given in IEC 60068-1:1988, 5.3.1:
– temperature: 15 °C to 35 °C;
– relative humidity: 25 % to 75 %;
– air pressure: 86 kPa to 106 kPa.
In the event of a dispute, or if required, the measurements shall be repeated using one of the
referee conditions as given in 10.1.2.
If it is difficult to carry out the measurement under the standard conditions, the tests and
measurements may be carried out under conditions other than the standard ones if there is no
dispute for referee.
10.1.2 Referee condition
The referee condition shall be one of the standard atmospheres for referee measurements
and tests taken from IEC 60068-1:1988, 5.2, below:
– temperature: 18 °C to 22 °C;
– relative humidity: 60 % to 70 %;
– air pressure: 86 kPa to 106 kPa.
10.2 Visual examination and check of dimensions
10.2.1 Visual examination
10.2.1.1 Test methods
The inductors shall be visually examined.
If required, a visual examination may be carried out with suitable equipment with appropriate
magnification agreed upon between manufacturer and user.
10.2.1.2 Requirements
There shall be no visible damage and, if applicable, the marking shall be legible.
10.2.2 Dimensions
10.2.2.1 Test methods
The test for dimensions shall be carried out using the vernier callipers of Class 2 or of a
higher class, specified in ISO 3599 or ISO 6906, or the micrometer callipers for external
measurement specified in ISO 3611.
However, other measuring instruments may be used, unless doubt arises for referee.
10.2.2.2 Requirements
The dimensions shall meet the requirements of 6.3 or the requirements specified in the detail
specification.
62674-1  IEC:2012 – 15 –
10.3 Electrical performance tests
10.3.1 Inductance
10.3.1.1 Measuring methods
For inductors with 1 µH or more, the inductance shall be measured by the bridge method
(10.3.1.1.1), the vector voltage/current method (10.3.1.1.2) or the automatic balancing bridge
method (10.3.1.1.3). For inductors less than 1 µH, the inductance shall be measured by the
vector voltage/current method prescribed in IEC 62024-1:2008, 3.1.
10.3.1.1.1 Bridge method
The bridge method is as follows:
a) Measuring circuit
An example of a measuring circuit is shown in Figure 2.

C
R
R
R
D
～
G
L
X
L
R
C
d
IEC  1857/12
Key
Components
G Signal generator
D Detector
C Standard capacitor
R
L Inductor under test
X
L Inductance of inductor under test
C Distributed capacitance of inductor under test
d
, R , R Variable resistors
R
1 2 3
Figure 2 – Example of circuit for measurement by the bridge method
b) Measuring method and calculation formula
Using the circuit given in Figure 2, the frequency and output of the signal generator shall
be adjusted to the respective values specified in the detail specification.
The inductor under test shall be connected and R , R and R shall be adjusted so that the
1 2 3
indication of the detector may become the minimum, and the resistances of R and R shall
1 3
be read and the inductance L shall be calculated from the following formula:
L = C × R × R
R 1 3
– 16 – 62674-1  IEC:2012
where
L is the inductance of the inductor under test;
C is the capacitance of the standard capacitor;
R
R , R is the resistance of the variable resistors.
1 3
c) Precaution for measurement
The specified value of the measuring frequency shall be selected in such a way, to
minimize errors in the measurement, so that the reactance in the distributed capacitance of
the inductor under test becomes large enough as compared with the reactance in the
inductance of inductor under test.
10.3.1.1.2 Vector voltage/current method
The vector voltage/current method is as follows:
a) Measuring circuit
An example of a measuring circuit is shown in Figure 3.

Ev
R
L
x
R
g L
s
C
d
R
Ev s
G
IEC  1858/12
Key
Components
R Source resistance of signal generator (50 Ω)
g
R Resistor
L Inductor under test
X
L Series inductance of inductor under test
s
C Distributed capacitance of inductor under test
d
R Series resistance of inductor under test
s
Phase reference signal
Ev，Ev Vector voltmeter
1 2
G Signal generator
Figure 3 – Example of circuit for measurement by the vector voltage/current method
b) Measuring method and calculation formula
Using the circuit given in Figure 3, the frequency and output of the signal generator shall
be adjusted to the respective values specified in the detail specification.

62674-1  IEC:2012 – 17 –
The inductor under test shall be connected and E and E shall be measured by the vector
1 2
voltmeter and the inductance L shall be calculated from the following formula:
 
E
Im R ×
 
E
 2 
L =
2πf
where
L is the inductance of inductor under test;
Im is the imaginary part of the complex value;
R is the resistance of the resistor;
E is the value indicated on vector voltmeter Ev ;
1 1
E is the value indicated on vector voltmeter Ev ;
2 2
f is the frequency of signal generator.
c) Precaution for measurement
If required, open-short compensation shall be performed prior to measurements.
10.3.1.1.3 Automatic balancing bridge method
The automatic balancing bridge method is as follows:
a) Measuring circuit
An example of a measuring circuit is shown in Figure 4.

I
R L R r
s I r
x
E
−
+
E
f 2
V
IEC  1859/12
Figure 4 – Example of a circuit for measurement by
the automatic balancing bridge method
b) Measuring method and calculation formula
Using the circuit given in Figure 4, the frequency f and output voltage E of the signal
generator shall be adjusted to the respective values specified in the detail specification.
The inductor under test shall be connected and E shall be measured by the vector
voltmeter and the inductance L shall be calculated from the following formula:

– 18 – 62674-1  IEC:2012
E −E R
1 1 x
Z = =
x
I E
x 2
E
Z = R = R + jX
x x x x
E ∠ − θ
X
x
L =
2πf
where
Z is the impedance of inductor under test;
x
R is the real part of impedance;
x
X is the imaginary part of impedance;
x
R is the resistance of resistor R ;
s s
R is the resistance of resistor R ;
r r
θ is the phase angle.
c) Precaution for measurement
If required, open-short compensation shall be performed prior to measurements.
10.3.1.2 Requirements
The inductance shall meet the requirements of 7.1 and 7.2, or the requirements specified in
the detail specification.
10.3.2 Q
10.3.2.1 Test methods
10.3.2.1.1 General
For inductors with 1 µH or more, Q shall be measured by the series resonance method
(10.3.2.1.2), the parallel resonance method (10.3.2.1.3) or the automatic balancing bridge
method (10.3.2.1.5). For inductors less than 1 µH, Q shall be measured by the vector
voltage/current method (10.3.2.1.4) as prescribed in IEC 62024-1:2008, 3.2.
10.3.2.1.2 Series resonance method
The series resonance method is as follows:
a) Measuring circuit
62674-1  IEC:2012 – 19 –
An example of a measuring circuit is shown in Figure 5.

L
Z
K
C
d
L
X
C E
E
V
E 2
～
G
IEC  1860/12
Key
Components
G Signal generator
Z Coupling impedance
K
C Variable capacitor
L Inductor under test
X
L Inductance of inductor under test
C Distributed capacitance of inductor under test
d
E Electronic voltmeter
V
Figure 5 – Example of circuit for measurement by the series resonance method
b) Measuring method and calculation formula
Using the circuit given in Figure 5, the frequency and output of the signal generator shall
be adjusted to the respective values specified in the detail specification.
The inductor under test shall be connected and the variable capacitor shall be adjusted so
that the voltage E may become a maximum, and then the voltage E shall be read and Q
2 2
shall be calculated from one of the following formulas:
E  C 
2 d
1) Q = 1 +
 
E C
 
E
2) Q = to be used when there is no doubt even if C is ignored.
d
E
where,
E is the output voltage of signal generator;
E is the indicated value of electronic voltmeter Ev;
C is the capacitance of variable capacitor;
C is the distributed capacitance of inductor under test.
d
10.3.2.1.3 Parallel resonance method
The parallel resonance method is as follows:
a) Measuring circuit
– 20 – 62674-1  IEC:2012
An example of a measuring circuit is shown in Figure 6.

C C
1 2
R
g
R
C L
E C L L
d X E
1 V
～ E
G
IEC  1861/12
Key
Components
G Signal generator
R Source resistance of signal generator (50 Ω)
g
C，C Coupling capacitors
1 2
C Tuning capacitor
L Inductor under test
X
L Inductance of inductor under test
C Distributed capacitance of inductor under test
d
E Electronic voltmeter
V
R Input resistor of electronic voltmeter
L
NOTE A suitably calibrated network analyser may be used in place of the signal generator and RF voltmeter.
Figure 6 – Example of a circuit for measurement by the parallel resonance method
b) Measuring method and calculation formula
Using the circuit given in Figure 6, the frequency and output of the signal generator shall
be adjusted to the respective values specified in the detail specification.
The variable capacitor shall be adjusted so that the voltage E may become a maximum. At
that time, fine-tuning may be performed by tuning of the frequency of the signal generator.
Then f and f , where E is 3 dB less than E (see Figure 7), shall be read and Q shall
1 2 2 2 max
be calculated from the following formula:
f + f
1 2
Q =
2 f − f
1 2
f
f
1 r f
IEC  1862/12
Figure 7 – Tuning characteristics of inductor
－3 dB
62674-1  IEC:2012 – 21 –
c) Precaution for measurement
The precautions for measurements are as follows:
1) The capacitance of coupling capacitors C and C shall be small enough as compared
1 2
to the capacitance of the tuning capacitor C;
2) The output voltage E of the signal generator shall be a value within the range where
the inductor under test is not saturated, and where the value of E also rises by 3 dB
when the output voltage is raised by 3 dB.
10.3.2.1.4 Vector voltage/current method
The vector voltage/current method is as follows:
a) Measuring circuit
An example of a measuring circuit is shown in Figure 3.
b) Measuring method and calculation formula
Using the circuit given in Figure 3, the frequency and output of the signal generator shall
be adjusted to the respective values specified in the detail specification.
The inductor under test shall be connected and then the voltages E and E shall be
1 2
measured by the vector voltmeter and Q shall be calculated from the following formula:
 
E
Im 
 
E
 2 
Q =
 
E
Re 
 
E
 2 
where
Q is Q of the inductor under test;
Re is the real part of the complex value;
Im is the imaginary part of the complex value;
E is the indicated value of vector voltmeter Ev ;
1 1
E is the indicated value of vector voltmeter Ev .
2 2
10.3.2.1.5 Automatic balancing bridge method
The automatic balancing bridge method is as follows:
a) Measuring circuit
An example of a measuring circuit is shown in Figure 4.
b) Measuring method and calculation formula
Using the circuit given in Figure 4, the frequency f and output voltage E of the signal
generator shall be adjusted to the respective values specified in the detail specification.
The inductor under test L shall be connected and the voltage E shall be measured and Q
x 2
shall be calculated from the following formula:

– 22 – 62674-1  IEC:2012
E −E R
1 1 r
Z = =
x
I E
r 2
E
Z = R = R + jX
x r x x
E ∠ − θ
X
x
Q =
R
x
where
Z is the impedance of the inductor under test;
x
R is the real part of impedance;
x
X is the imaginary part of impedance;
x
R is the resistance of resistor R ;
s s
R is the resistance of resistor R ;
r r
θ is the phase angle.
10.3.2.2 Requirements
Q shall meet the requirements specified in the detail specification.
10.3.3 Impedance
10.3.3.1 Test methods
For inductors with 1 µH or more, the impedance shall be measured by the automatic
balancing bridge method (10.3.1.1.3). For inductors less than 1 µH, the impedance shall be
measured by the vector voltage/current method as prescribed in IEC 62024-1:2008, 3.3.
10.3.3.2 Requirements
The impedance shall meet the requirements specified in the detail specification.
10.3.4 Self-resonant frequency
10.3.4.1 Test methods
10.3.4.1.1
...