Conventions concerning electric and magnetic circuits

Lays down rules for signs and reference directions and reference polarities for electric currents and voltages in electric networks, as well as for the corresponding quantities in magnetic circuits.

Vereinbarungen für Stromkreise und magnetische Kreise

Conventions concernant les circuits électriques et magnétiques

Établit des règles pour les signes, sens de référence et polarités de référence des courants électriques et des tensions dans les réseaux électriques, ainsi que pour les grandeurs correspondantes dans les circuits magnétiques.

Conventions concerning electric and magnetic circuits (IEC 60375:2003)

General Information

Status
Withdrawn
Publication Date
09-Sep-2003
Current Stage
6060 - Document made available
Due Date
10-Sep-2003
Completion Date
10-Sep-2003

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SLOVENSKI SIST EN 60375:2004
STANDARD
julij 2004
Conventions concerning electric and magnetic circuits (IEC 60375:2003)
ICS 17.220.01 Referenčna številka
SIST EN 60375:2004(en)

© Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

---------------------- Page: 1 ----------------------
EUROPEAN STANDARD EN 60375
NORME EUROPÉENNE
EUROPÄISCHE NORM September 2003
ICS 17.220.01
English version
Conventions concerning electric and magnetic circuits
(IEC 60375:2003)
Conventions concernant les circuits Vereinbarungen für Stromkreise
électriques et magnétiques und magnetische Kreise
(CEI 60375:2003) (IEC 60375:2003)

This European Standard was approved by CENELEC on 2003-09-01. 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 Central Secretariat 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 Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,

Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 60375:2003 E
---------------------- Page: 2 ----------------------
EN 60375:2003 - 2 -
Foreword

The text of document 25/261/FDIS, future edition 2 of IEC 60375, prepared by IEC TC 25, Quantities

and units, and their letter symbols, was submitted to the IEC-CENELEC parallel vote and was

approved by CENELEC as EN 60375 on 2003-09-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2004-06-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2006-09-01
Annexes designated "normative" are part of the body of the standard.
In this standard, annex ZA is normative.
Annex ZA has been added by CENELEC.
__________
Endorsement notice

The text of the International Standard IEC 60375:2003 was approved by CENELEC as a European

Standard without any modification.
__________
---------------------- Page: 3 ----------------------
- 3 - EN 60375:2003
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

This European Standard incorporates by dated or undated reference, provisions from other

publications. These normative references are cited at the appropriate places in the text and the

publications are listed hereafter. For dated references, subsequent amendments to or revisions of any

of these publications apply to this European Standard only when incorporated in it by amendment or

revision. For undated references the latest edition of the publication referred to applies (including

amendments).

NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant

EN/HD applies.
Publication Year Title EN/HD Year
IEC 60050-121 1998 International Electrotechnical - -
Vocabulary (IEV)
Part 121: Electromagnetism
IEC 60050-131 2002 Part 131: Circuit theory - -
IEC 60617 Series Graphical symbols for diagrams EN 60617 Series
---------------------- Page: 4 ----------------------
NORME CEI
INTERNATIONALE IEC
60375
INTERNATIONAL
Deuxième édition
STANDARD
Second edition
2003-06
Conventions concernant les circuits
électriques et magnétiques
Conventions concerning electric
and magnetic circuits
© IEC 2003 Droits de reproduction réservés ⎯ Copyright - all rights reserved

Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any

utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including

électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from

microfilms, sans l'accord écrit de l'éditeur. the publisher.

International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland

Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch

CODE PRIX
Commission Electrotechnique Internationale PRICE CODE
International Electrotechnical Commission
ɆɟɠɞɭɧɚɪɨɞɧɚɹɗɥɟɤɬɪɨɬɟɯɧɢɱɟɫɤɚɹɄɨɦɢɫɫɢɹ
Pour prix, voir catalogue en vigueur
For price, see current catalogue
---------------------- Page: 5 ----------------------
60375 © IEC:2003 – 3 –
CONTENTS

FOREWORD .......................................................................................................................... 5

1 Scope .............................................................................................................................. 7

2 Normative references....................................................................................................... 7

3 Terms and definitions ...................................................................................................... 7

4 Direction rules for current ...............................................................................................11

4.1 Physical direction of current...................................................................................11

4.2 Reference direction of current................................................................................11

4.3 Indication of the reference direction for currents ....................................................11

4.4 Kirchhoff law for nodes ..........................................................................................13

5 Polarity rules ..................................................................................................................15

5.1 Voltage..................................................................................................................15

5.2 Reference polarity for a pair of nodes ....................................................................15

5.3 Indication of the reference polarity.........................................................................15

5.4 Kirchhoff law for meshes........................................................................................19

6 Conventions concerning two-terminal passive networks..................................................19

6.1 General conventions..............................................................................................19

6.2 Resistive element ..................................................................................................19

6.3 Inductive element ..................................................................................................21

6.4 Capacitive element ................................................................................................21

6.5 Non-ideal two-terminal circuit elements .................................................................21

7 Conventions for two-port networks..................................................................................23

8 Conventions concerning sources ....................................................................................23

8.1 Conventions concerning voltage sources ...............................................................23

8.2 Conventions concerning current sources ...............................................................25

9 Conventions concerning magnetic circuits.......................................................................27

9.1 Magnetic flux .........................................................................................................27

9.2 Linked flux .............................................................................................................29

9.3 Conventions concerning mutual inductance ...........................................................29

10 Complex notation............................................................................................................31

10.1 Conventions concerning complex representation of sinusoidal quantities...............31

10.2 Reference direction of a complex current...............................................................33

10.3 Reference polarity for a complex voltage ...............................................................33

10.4 Complex representation of Ohm’s law....................................................................35

10.5 Conventions concerning the graphical representation of phasors...........................37

10.6 Conventions concerning phase differences ............................................................37

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60375 © IEC:2003 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CONVENTIONS CONCERNING ELECTRIC
AND MAGNETIC CIRCUITS
FOREWORD

1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote

international co-operation on all questions concerning standardization in the electrical and electronic fields. To

this end and in addition to other activities, the IEC publishes International Standards. Their preparation is

entrusted to technical committees; any IEC National Committee interested in the subject dealt with may

participate in this preparatory work. International, governmental and non-governmental organizations liaising

with the IEC also participate in this preparation. The IEC collaborates closely with the International

Organization for Standardization (ISO) in accordance with conditions determined by agreement between the

two organizations.

2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an

international consensus of opinion on the relevant subjects since each technical committee has representation

from all interested National Committees.

3) The documents produced have the form of recommendations for international use and are published in the form

of standards, technical specifications, technical reports or guides and they are accepted by the National

Committees in that sense.

4) In order to promote international unification, IEC National Committees undertake to apply IEC International

Standards transparently to the maximum extent possible in their national and regional standards. Any

divergence between the IEC Standard and the corresponding national or regional standard shall be clearly

indicated in the latter.

5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any

equipment declared to be in conformity with one of its standards.

6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject

of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60375 has been prepared by IEC technical committee 25:

Quantities and units, and their letter symbols.

This second edition cancels and replaces the first edition issued in 1972, and constitutes

a technical revision.
The text of this standard is based on the following documents:
FDIS Report on voting
25/261/FDIS 25/266/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.

The committee has decided that the contents of this publication will remain unchanged until 2008.

At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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60375 © IEC:2003 – 7 –
CONVENTIONS CONCERNING ELECTRIC
AND MAGNETIC CIRCUITS
1 Scope

This International Standard lays down rules for signs and reference directions and reference

polarities for electric currents and voltages in electric networks, as well as for the

corresponding quantities in magnetic circuits.

In Clauses 3 to 9, the time dependence is arbitrary. Clause 10 details the rules and recom-

mendations for complex notation.
2 Normative references

The following referenced documents are indispensable for the application 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.

IEC 60050-121:1998, International Electrotechnical Vocabulary (IEV) – Part 121: Electro-

magnetism

IEC 60050-131:2002, International Electrotechnical Vocabulary (IEV) – Part 131: Circuit theory

IEC 60617, Graphical symbols for diagrams
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
terminal

point of interconnection of an electric circuit element, an electric circuit or a network

(IEC 60050-131:2002, 131-13-03) with other electric circuit elements, electric circuits or

networks
[IEV-131-11-11]

NOTE 1 For an electric circuit element, the terminals are the points at which or between which the related integral

quantities are defined. At each terminal, there is only one electric current from outside into the element.

NOTE 2 The term “terminal” has a related meaning in IEC 60050-151.
3.2
circuit element

in electromagnetism, mathematical model of a device characterized by one or more relations

between integral quantities
[IEV-131-11-03]
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60375 © IEC:2003 – 9 –
3.3
two-terminal element
electric circuit element having two terminals
[IEV 131-11-16]
3.4
n-terminal circuit element
electric circuit element having n terminals with generally n > 2
[IEV-131-11-13]
NOTE For an n-terminal electric circuit element:

1) the algebraic sum of the electric currents into the element through the terminals is zero at any instant;

2) there are n – 1 independent relations between integral quantities.
3.5
network

in network topology, set of ideal circuit elements and their interconnections, considered as

a whole
[IEV-131-13-03]

NOTE 1 The term “electric network” is defined in IEC 60050-131-11-07 and in IEC 60050-151.

NOTE 2 In diagrams in this standard, a box, IEC 60617 symbol, represents any network, unless otherwise

specified.
3.6
branch

subset of a network, considered as a two-terminal circuit, consisting of a circuit element or

a combination of circuit elements
[IEV-131-13-06]
3.7
node, vertex (US)
end-point of a branch connected or not to one or more other branches
[IEV-131-13-07]
3.8
loop
closed path passing only once through any node
[IEV-131-13-12]
3.9
tree

connected set of branches joining all the nodes of a network without forming a loop

[IEV-131-13-13]
3.10
co-tree
set of the branches of a network not included in a chosen tree
[IEV-131-13-14]
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60375 © IEC:2003 – 11 –
3.11
link
branch of a co-tree
[IEV-131-13-15]
3.12
mesh
set of branches forming a loop and containing only one link of a given co-tree
[IEV-131-13-16]

Remark: The English terms voltage, electric potential difference, and electric tension have

the same meaning in the area of electric circuits. In the English language version of the IEV

voltage is the preferred term and electric tension, often shortened to tension, is an alternative.

This standard uses the term voltage. The term electric current is often shortened to current

according to IEC 60050-121.

For electric networks with lumped circuit elements (see IEC 60050-131), the Kirchhoff law for

nodes (see 4.4) applies for the quantity current, and the Kirchhoff law for meshes (see 5.4)

applies for the quantity voltage.
4 Direction rules for current
4.1 Physical direction of current

The net flow of electric charge through a surface is referred to as electric current. By

convention, the physical direction of the current i is defined as the direction corresponding to

the movement of positive charge. If the quasi-infinitesimal charge dq passes through a

predetermined surface, for example the cross-section of a conductor, during the duration dt,

the electric current is
i =
4.2 Reference direction of current

The reference direction for the current in a branch or in a mesh is a direction fixed arbitrarily

along the branch or around the mesh. A current is considered as positive when its physical

direction corresponds to the reference direction.
4.3 Indication of the reference direction for currents
4.3.1 Indication of the reference direction for currents for a branch

An arrow having the direction corresponding to the reference direction for a current is placed on

or near the line representing the branch element, or near the branch element. (See Figure 1.)

The notations in Figures 1a and 1b are preferred.
Figure 1c
Figure 1a Figure 1d
Figure 1b
Figure 1 í Indication of the reference direction for a current by an arrow
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60375 © IEC:2003 – 13 –

When there is only one branch between two nodes, it is clearer to use the notations for the

nodes (a and b in Figure 2) to denote the direction of the current, in this case i , which

defines a current directed from a to b in a branch ab. It is useful to combine consistently

the indication by an arrow and by using node designations as in Figure 2. The notations in

Figures 2a and 2b are preferred.
ab ab
Figure 2a Figure 2b Figure 2c Figure 2d

Figure 2 í Indication of the reference direction for a current using the node names

4.3.2 Indication of the reference direction for mesh currents

To indicate in a diagram the reference direction for the current around a mesh, a curved arrow

having a corresponding direction is placed in the mesh so as to follow its contour. In Figure 3,

an example shows the connection between mesh currents and branch currents.
Figure 3 – Indication of the reference direction for mesh currents
4.4 Kirchhoff law for nodes
The Kirchhoff law for nodes states:

The algebraic sum of the branch currents towards any node of an electric network is zero (see

IEC 60050-131:2002, 131-15-09). According to the currents defined in Figure 4a, this means

that the Kirchhoff law for nodes applied to node e reads
i +i +i +i = 0
ae be ce de

If the reference direction of a current, for example the current in branch between b and e in

Figure 4b, is chosen as away from the node e, the corresponding current ii==−== −−− , shall be

eb be
taken with the opposite sign. In that case, the Kirchhoff law for nodes states:
i −i +i +i = 0
ae eb ce de
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60375 © IEC:2003 – 15 –
Figure 4a Figure 4b
Figure 4 í Examples of the Kirchhoff law for nodes
5 Polarity rules for voltage
5.1 Voltage

In an electric network, a voltage between two ordered nodes, a and b, is the difference of the

electric potentials at node a and node b.
5.2 Reference polarity for a pair of nodes

The polarity of a pair of nodes is determined by the ordering of the nodes. The reference

polarity may be chosen arbitrarily.
...

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