SIST EN IEC 60738-1:2023

SLOVENSKI STANDARD
SIST EN IEC 60738-1:2023
01-januar-2023
Nadomešča:
SIST EN 60738-1:2007
SIST EN 60738-1:2007/A1:2010
Termistorji - Neposredno ogrevani s pozitivnim temperaturnim koeficientom - 1.
del: Splošna specifikacija (IEC 60738-1:2022)
Thermistors - Directly heated positive temperature coefficient - Part 1: Generic
specification (IEC 60738-1:2022)
Direkt geheizte temperaturabhängige Widerstände mit positivem Temperaturkoeffizienten
– Teil 1: Fachgrundspezifikation (IEC 60738-1:2022)
Thermistances - Coefficient de température positif à chauffage direct - Partie 1:
Spécification générique (IEC 60738-1:2022)
Ta slovenski standard je istoveten z: EN IEC 60738-1:2022
ICS:
31.040.30 Termistorji Thermistors
SIST EN IEC 60738-1:2023 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN IEC 60738-1:2023

---------------------- Page: 2 ----------------------
SIST EN IEC 60738-1:2023


EUROPEAN STANDARD EN IEC 60738-1

NORME EUROPÉENNE

EUROPÄISCHE NORM November 2022
ICS 31.040.30 Supersedes EN 60738-1:2006; EN 60738-1:2006/A1:2009
English Version
Thermistors - Directly heated positive temperature coefficient -
Part 1: Generic specification
(IEC 60738-1:2022)
Thermistances - Coefficient de température positif à Direkt geheizte temperaturabhängige Widerstände mit
chauffage direct - Partie 1: Spécification générique positivem Temperaturkoeffizienten - Teil 1:
(IEC 60738-1:2022) Fachgrundspezifikation
(IEC 60738-1:2022)
This European Standard was approved by CENELEC on 2022-11-18. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.



European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
 Ref. No. EN IEC 60738-1:2022 E

---------------------- Page: 3 ----------------------
SIST EN IEC 60738-1:2023
EN IEC 60738-1:2022 (E)
European foreword
The text of document 40/2969/FDIS, future edition 4 of IEC 60738-1, prepared by IEC/TC 40
"Capacitors and resistors for electronic equipment" was submitted to the IEC-CENELEC parallel vote
and approved by CENELEC as EN IEC 60738-1:2022.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2023-08-18
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2025-11-18
document have to be withdrawn
This document supersedes EN 60738-1:2006 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 60738-1:2022 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated:
IEC 60068-2-45:1980 NOTE Harmonized as EN 60068-2-45:1992 (not modified)
2

---------------------- Page: 4 ----------------------
SIST EN IEC 60738-1:2023
EN IEC 60738-1:2022 (E)
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications
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.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60027 series Letters symbols to be used in electrical - series
technology
IEC 60050 series International Electrotechnical Vocabulary - -
(IEV)
IEC 60062 - Marking codes for resistors and capacitors EN 60062 -
IEC 60068-1 2013 Environmental testing - Part 1: General and EN 60068-1 2014
guidance
IEC 60068-2-1 2007 Environmental testing - Part 2-1: Tests - EN 60068-2-1 2007
Test A: Cold
IEC 60068-2-2 2007 Environmental testing - Part 2-2: Tests - EN 60068-2-2 2007
Test B: Dry heat
IEC 60068-2-6 - Environmental testing - Part 2-6: Tests - EN 60068-2-6 -
Test Fc: Vibration (sinusoidal)
IEC 60068-2-11 - Environmental testing - Part 2-11: Tests - EN IEC 60068-2-11 -
Test Ka: Salt mist
IEC 60068-2-13 - Environmental testing - Part 2-13: Tests - EN IEC 60068-2-13 -
Test M: Low air pressure
IEC 60068-2-14 - Environmental testing - Part 2-14: Tests - EN 60068-2-14 -
Test N: Change of temperature
IEC 60068-2-20 - Environmental testing - Part 2-20: Tests - EN IEC 60068-2-20 -
Test Ta and Tb: Test methods for
solderability and resistance to soldering
heat of devices with leads
IEC 60068-2-21 - Environmental testing - Part 2-21: Tests - EN IEC 60068-2-21 -
Test U: Robustness of terminations and
integral mounting devices
IEC 60068-2-27 - Environmental testing - Part 2-27: Tests - EN 60068-2-27 -
Test Ea and guidance: Shock
IEC 60068-2-30 - Environmental testing - Part 2-30: Tests - EN 60068-2-30 -
Test Db: Damp heat, cyclic (12 h + 12 h
cycle)
3

---------------------- Page: 5 ----------------------
SIST EN IEC 60738-1:2023
EN IEC 60738-1:2022 (E)
Publication Year Title EN/HD Year
IEC 60068-2-58 - Environmental testing - Part 2-58: Tests - EN 60068-2-58 -
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 - EN 60068-2-78 -
Test Cab: Damp heat, steady state
IEC 60294 - Measurement of the dimensions of a EN 60294 -
cylindrical component with axial
terminations
IEC 60617 - Standard data element types with - -
associated classification scheme for
electric components - Part 4: IEC reference
collection fo standard data element types
and component classes
IEC 60717 - Method for the determination of the space EN 60717 -
required by capacitors and resistors with
unidirectional terminations
IEC 61193-2 - Quality assessment systems - Part 2: EN 61193-2 -
Selection and use of sampling plans for
inspection of electronic components and
packages
IEC 61249-2-7 - Materials for printed boards and other EN 61249-2-7 -
interconnecting structures - Part 2-7:
Reinforced base materials clad and unclad
- Epoxide woven E-glass laminated sheet
of defined flammability (vertical burning
test), copper-clad
IEC 61760-1 - Surface mounting technology - Part 1: EN IEC 61760-1 -
Standard method for the specification of
surface mounting components (SMDs)
ISO 80000-1 - Quantities and units - Part 1: General EN ISO 80000-1 -

4

---------------------- Page: 6 ----------------------
SIST EN IEC 60738-1:2023




IEC 60738-1

®


Edition 4.0 2022-10




INTERNATIONAL



STANDARD




NORME


INTERNATIONALE
colour

inside










Thermistors – Directly heated positive temperature coefficient –

Part 1: Generic specification



Thermistances – Coefficient de température positif à chauffage direct –

Partie 1: Spécification générique
















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 31.040.30 ISBN 978-2-8322-5731-9




Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

---------------------- Page: 7 ----------------------
SIST EN IEC 60738-1:2023
– 2 – IEC 60738-1:2022 © IEC 2022
CONTENTS
FOREWORD . 7
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 10
4 General requirements . 19
4.1 Units and symbols. 19
4.2 Preferred values . 20
4.2.1 Climatic categories . 20
4.2.2 Spacings . 20
4.3 Marking . 20
4.3.1 General . 20
4.3.2 Coding . 21
5 General provisions for measurements and test method . 21
5.1 General . 21
5.2 Standard conditions for testing . 21
5.2.1 Standard atmospheric conditions for testing . 21
5.2.2 Error of measurement . 21
5.3 Drying and recovery . 21
5.3.1 Drying . 21
5.3.2 Recovery . 22
5.3.3 Shock test severities . 22
5.3.4 Vibration severities . 22
5.4 Mounting (for surface mount thermistors only) . 22
5.4.1 General . 22
5.4.2 Printed wiring board and land pattern . 23
5.4.3 Wave soldering method . 23
5.4.4 Reflow soldering method . 23
6 Electrical tests and measurements . 24
6.1 Zero-power resistance . 24
6.1.1 General . 24
6.1.2 Measurement procedures . 24
6.1.3 Requirements . 25
6.2 Temperature coefficient of resistance . 25
6.2.1 General . 25
6.2.2 Requirements . 25
6.3 Insulation resistance (for insulated types only) . 25
6.3.1 General . 25
6.3.2 Test methods . 25
6.3.3 Applied voltage . 26
6.3.4 Requirements . 26
6.4 Voltage proof (for insulated types only) . 26
6.4.1 General . 26
6.4.2 Test methods . 26
6.4.3 Test voltage . 26
6.4.4 Requirements . 26
6.5 Resistance/temperature characteristic . 26

---------------------- Page: 8 ----------------------
SIST EN IEC 60738-1:2023
IEC 60738-1:2022 © IEC 2022 – 3 –
6.5.1 Test methods . 26
6.5.2 Requirements . 27
6.6 Dissipation factor at U (δ) . 27
max
6.6.1 General . 27
6.6.2 Preconditioning . 27
6.6.3 Test circuit . 27
6.6.4 Test methods . 27
6.6.5 Requirements . 28
6.7 Response time by ambient temperature change (t ) . 28
a
6.7.1 General . 28
6.7.2 Preconditioning . 28
6.7.3 Test procedures . 28
6.7.4 Measurement procedures . 29
6.7.5 Requirements . 29
6.8 Response time by power change (t ) . 29
p
6.8.1 Mounting . 29
6.8.2 Test methods . 29
6.9 Thermal time constant by ambient temperature change (τ ) . 30
a
6.10 Thermal time constant by cooling (τ ) . 30
c
6.10.1 Mounting . 30
6.10.2 Test methods . 30
6.10.3 Requirements . 32
6.11 Tripping current and tripping time. 32
6.12 Non-tripping current . 32
6.13 Residual current. 32
6.14 Surface temperature . 33
6.15 Inrush current . 34
6.15.1 Measuring circuit . 34
6.15.2 Measuring method . 34
6.16 Energy by discharge . 35
6.16.1 Measuring circuit . 35
6.16.2 Measuring method . 35
7 Mechanical test and measurements . 36
7.1 Visual examination and check of dimensions . 36
7.1.1 Visual examination . 36
7.1.2 Marking . 36
7.1.3 Dimensions (gauging) . 36
7.1.4 Dimensions (detail) . 36
7.2 Robustness of terminations . 36
7.2.1 General . 36
7.2.2 Test Ua – Tensile . 36
1
7.2.3 Test Ub – Bending . 37
7.2.4 Test Uc – Torsion . 37
7.2.5 Visual examination . 37
7.2.6 Final measurements and requirements . 37
7.3 Vibration . 37
7.4 Shock . 38
7.5 Shear (adhesion) test . 38

---------------------- Page: 9 ----------------------
SIST EN IEC 60738-1:2023
– 4 – IEC 60738-1:2022 © IEC 2022
7.5.1 Test conditions . 38
7.5.2 Test methods . 38
7.5.3 Requirements . 38
7.6 Substrate bending test . 38
7.6.1 Mounting . 38
7.6.2 Initial measurements . 39
7.6.3 Test procedures . 39
7.6.4 Measurements . 39
7.6.5 Requirements . 39
7.6.6 Final inspection and requirements . 39
8 Environmental and climatic tests . 39
8.1 Rapid change of temperature . 39
8.2 Climatic sequence. 39
8.2.1 General . 39
8.2.2 Initial measurements . 39
8.2.3 Dry heat . 40
8.2.4 Damp heat (cyclic), first cycle . 40
8.2.5 Cold. 40
8.2.6 Low air pressure . 40
8.2.7 Damp heat (cyclic), remaining cycles . 40
8.2.8 Final measurements . 40
8.3 Damp heat, steady state . 41
8.4 Endurance . 41
8.4.1 Endurance at room temperature (cycling) . 41
8.4.2 Endurance at upper category temperature . 42
8.4.3 Endurance at maximum operating temperature and maximum voltage . 43
8.4.4 Cold environment electrical cycling . 44
8.4.5 Thermal runaway . 45
9 Test related to component assembly . 45
9.1 Solderability . 45
9.1.1 General . 45
9.1.2 Thermistors with leads . 45
9.1.3 Surface mount thermistors . 46
9.2 Resistance to soldering heat . 46
9.2.1 General . 46
9.2.2 Test conditions . 46
9.2.3 The period of recovery . 47
9.2.4 Requirements for except surface mount thermistors . 47
9.2.5 Requirements for surface mount thermistors . 47
10 Quality assessment procedures . 47
Annex A (informative) Mounting for electrical measurements . 48
A.1 Mounting for thermistors without wire terminations . 48
A.2 Mounting for thermistors with wire terminations . 48
A.3 Mounting for surface mount thermistors . 49
Annex B (informative) Mounting for temperature measurements . 51
Annex Q (normative) Quality assessment procedures . 52
Q.1 General . 52
Q.2 Applicability of qualification approval . 52

---------------------- Page: 10 ----------------------
SIST EN IEC 60738-1:2023
IEC 60738-1:2022 © IEC 2022 – 5 –
Q.3 Primary stage of manufacture . 52
Q.4 Subcontracting . 52
Q.5 Structurally similar components . 52
Q.5.1 General . 52
Q.5.2 For electrical tests . 53
Q.5.3 For environmental tests . 53
Q.5.4 For visual inspection . 53
Q.5.5 For endurance tests . 53
Q.6 Qualification approval procedures . 53
Q.6.1 Eligibility for qualification approval . 53
Q.6.2 Application for qualification approval . 53
Q.6.3 Test procedure for qualification approval . 53
Q.6.4 Qualification approval based on the fixed sample size procedure. 54
Q.6.5 Granting of qualification approval . 59
Q.6.6 Maintenance of qualification approval . 59
Q.6.7 Quality conformance inspection . 60
Q.7 Rework and repair. 61
Q.7.1 Rework . 61
Q.7.2 Repair . 61
Q.8 Release for delivery . 61
Q.8.1 General . 61
Q.8.2 Release for delivery under qualification approval before the completion
of group B tests . 62
Q.9 Certified test records of released lots . 62
Q.10 Delayed delivery . 62
Q.11 Alternative test methods . 62
Q.12 Manufacture outside the geographical limits .
...