FUNDAMENTALS OF ELECTRICAL ENGINEERING
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Technical University of Košice Faculty of Electrical Engineering & Informatics Department of Electric Power Engineering Ľubomír Beňa FUNDAMENTALS OF ELECTRICAL ENGINEERING Part II – Technical documentation in electrical engineering 2008 PREFACE This textbook is designed for the course „Fundamentals of Electrical Engineering“ attended in the first year of study at the Faculty of Electrical Engineering and Informatics at Technical University in Košice. This course is obligatory for every students of electrical engineering. The main purpose of this course is to give fundamental knowledge of: - technical standardisation, protection of industrial properties, - rules for technical documentation creation, - electrical diagrams drawing, - technical documentation for printed circuit board, - skills with drawing of technical documentation by the CAD tools. In Košice, August 2008 Author 2 CONTENTS 1 2 3 4 5 6 7 TECHNICAL STANDARDISATION ................................................................................................ 4 1.1 Types of Standards....................................................................................................................... 4 1.2 Enforcement................................................................................................................................. 5 1.3 Availability .................................................................................................................................. 5 1.4 Geographic levels......................................................................................................................... 6 1.5 Standards organisations ............................................................................................................... 6 1.5.1 International Standards Organisations................................................................................. 6 1.5.2 Regional Standards Organizations ...................................................................................... 7 1.5.3 National Standards Bodies (NSBs) ..................................................................................... 7 1.5.4 Slovak Standards Institute ................................................................................................... 9 PROTECTION OF INDUSTRIAL PROPERTIES ........................................................................... 14 2.1 Patents ........................................................................................................................................ 14 2.2 Utility models............................................................................................................................. 14 2.3 Design ........................................................................................................................................ 15 2.4 Trademark .................................................................................................................................. 15 TECHNICAL DRAWING................................................................................................................. 16 3.1 Lines on the engineering drawing.............................................................................................. 16 3.1.1 Lines styles and types........................................................................................................ 16 3.1.2 The usage of the lines in the drawings .............................................................................. 18 3.2 Drawing to Scale........................................................................................................................ 20 3.3 Lettering of the Drawings .......................................................................................................... 21 3.4 Standard paper sizes, position of standard sheets ...................................................................... 22 ORTHOGRAPHIC PROJECTION ................................................................................................... 24 BASIC RULES FOR DIMENSIONING........................................................................................... 27 ELECTRICAL DIAGRAMS DRAWING......................................................................................... 32 6.1 Graphical symbols for diagrams ................................................................................................ 32 6.1.1 Parts of IEC 60617 ............................................................................................................ 32 6.1.2 Parts of electronic component symbol .............................................................................. 32 6.1.3 Representation of electronic components.......................................................................... 34 6.1.4 Multi pole and single pole diagrams ................................................................................. 35 6.1.5 Labelling of electrical and electronic components............................................................ 36 6.1.6 Types of electro-technical diagrams.................................................................................. 37 TECHNICAL DOCUMENTATION FOR PRINTED CIRCUIT BOARD ...................................... 42 7.1 Main kinds of PCB..................................................................................................................... 43 7.2 Classes of PCB........................................................................................................................... 44 7.3 Complete documentation for manufacturing of PCB................................................................. 45 7.3.1 Sample and drawing of conductor pattern......................................................................... 46 7.3.2 Sample and drawing of standard holes.............................................................................. 47 7.3.3 Drawing of special holes ................................................................................................... 47 7.3.4 Sample of non-soldered mask ........................................................................................... 48 7.3.5 Sample of printing............................................................................................................. 49 7.3.6 Component location drawing of PCB ............................................................................... 49 7.3.7 Circuit diagram.................................................................................................................. 50 REFERENCES .................................................................................................................................52 3 1 TECHNICAL STANDARDISATION A technical standard is an established norm or requirement. It is usually a formal document that establishes uniform engineering or technical criteria, methods, processes and practices. A technical standard can also be a controlled artifact or similar formal means used for calibration. Reference Standards and certified reference materials have an assigned value by direct comparison with a reference base. A primary standard is usually under jurisdiction of a national standards body. Secondary, tertiary, check standards and standard materials may be used for reference in a metrology system. A key requirement in this case is (metrological) traceability, an unbroken paper trail of calibrations back to the primary standard. This text discusses formal technical standards. A custom, convention, company product, corporate standard, etc which becomes generally accepted and dominant is often called a de facto standard. A technical standard can be developed privately or unilaterally, for example by a corporation, regulatory body, military, etc. Standards can also be developed by groups such as trade unions, and trade associations. Standards organizations usually have more diverse input and usually develop voluntary standards: these might become mandatory if adopted by a government, business contract, etc. The standardization process may be by edict or may involve the formal consensus of technical experts. 1.1 Types of Standards The primary types of technical standards are: • • • a standard specification is an explicit set of requirements for an item, material, component, system or service. It is often used to formalize the technical aspects of a procurement agreement or contract. For example, there may be a specification for a turbine blade for a jet engine which defines the exact material and performance requirements. a standard test method describes a definitive procedure which produces a test result. It may involve making a careful personal observation or conducting a highly technical measurement. For example, a physical property of a material is often affected by the precise method of testing: any reference to the property should therefore reference the test method used. a standard procedure (or standard practice) gives a set of instructions for performing operations or functions. For example, there are detailed standard operating procedures for operation of a nuclear power plant. 4 • • a standard guide is general information or options which do not require a specific course of action. a standard definition is formally established terminology. 1.2 Enforcement Many standards are written as voluntary standards. Interested parties may participate in the development voluntarily and the use of the finished standard is voluntary. The standards organization usually does not have any way to impose their use or to enforce compliance. People and organizations may choose to use or not to use a published voluntary standard. Some standards are written to be mandatory standards. A defense standard is mandatory in relation to that use: It may be voluntarily referenced by a different organization. A standard written and published by a government regulator is mandatory for that use. (A standard which is enforced by law is sometimes called a de jure standard.) A corporation may write its own standard for its mandatory use. The use of some voluntary standards may sometimes become mandatory. • A voluntary standard may be referenced or adopted by a government or regulatory body. Its use becomes mandatory within the scope of its legal reference. Enforcement is by the regulator or government body which chose to reference the standard. • A voluntary standard may be referenced or adopted by a private organization or become part of a legal contract. The voluntary standard becomes mandatory within the scope of that usage or contract. • A voluntary standard may sometimes become so common and dominant that its use becomes expected. Enforcement of a de facto standard is usually by free market forces. 1.3 Availability • • • • Public documents available on the internet, public library, etc. (Some technical standards may be found at a major central library or at the library of a good technical university) Published documents which are available for purchase. Private documents owned by an organization or corporation. These are used and circulated as they determine necessary or useful. Documents open for public use but with intellectual property (copyright, etc) associated with them. 5 • Closed or controlled documents which contain trade secrets or classified information. 1.4 Geographic levels When a geographically defined community needs to solve a community-wide coordination problem, it can adopt an existing standard, or produce a new one. The main geographic levels are: • • • national standard, regional standard, international standard. National/Regional/International standards is one way of overcoming technical barriers in inter-local or inter-regional commerce caused by differences among technical regulations and standards developed independently and separately by each local, local standards organisation, or local company. Technical barriers arise when different groups come together, each with a large user base, doing some well established thing that between them is mutually incompatible. Establishing national/regional/international standards is one way of preventing or overcoming this problem. 1.5 Standards organisations A standards organisation is any entity whose primary activities are developing, coordinating, promulgating, revising, amending, reissuing, interpreting, or otherwise maintaining of standards. 1.5.1 International Standards Organisations Broadly, an international standards organization develops international standards. There are many international standards organizations. For example: • the International Organization for Standardization (ISO), • the International Electrotechnical Commission (IEC), • the International Telecommunication Union (ITU). have existed for more than 50 years (founded in 1947, 1906, and 1865, respectively) and they are all based in Geneva, Switzerland. They have established tens of thousands of standards covering almost every conceivable topic. Many of these are then adopted 6 worldwide replacing various incompatible 'homegrown' standards. Many of these standards are naturally evolved from those designed in-house within an industry, or by a particular country, whilst others have been built from scratch by groups of experts who sit on various technical committees (TCs). 1.5.2 Regional Standards Organizations Regional standards bodies also exist such as European Committee for Standardization (CEN), European Committee for Electrotechnical Standardization (CENELEC), European Telecommunications Standard Institute (ETSI), and the Institute for Reference Materials and Measurements (IRMM) in Europe, the Pacific Area Standards Congress (PASC), the Pan American Standards Commission (COPANT), the African Organization for Standardization (ARSO), the Arab Industrial Development and Mining Organization (AIDMO), and others. 1.5.3 National Standards Bodies (NSBs) In general, each country or economy has a single recognized Standards Body. Algeria - IANOR - Institut algérien de normalisation - Website Argentina - IRAM - Instituto Argentino de Normalización - Website Armenia - SARM - National Institute of Standards and Quality - Website Australia - SA - Standards Australia - Website Austria - ON - Austrian Standards Institute - Website Bangladesh - BSTI - Bangladesh Standards and Bangladesh Standards and Testing Institutio, - Website Belarus - BELST - Committee for Standardization, Metrology and Certification of Belarus - Website Belgium - IBN/BIN - The Belgian Institution for Standardization - Website Belgium - BEC/CEB - The Belgian Electrotechnical Committee - Website Bolivia - IBNORCA - Instituto Boliviano de Normalización y Calidad - Website Bosnia and Herzegovina - BASMP - Institute for Standards, Metrology and Intellectual Property of Bosnia and Herzegovina - Website Brazil - ABNT - Associação Brasileira de Normas Técnicas - Website Brunei Darussalam - CPRU - Construction Planning and Research Unit, Ministry of Development - Website Bulgaria - BDS - Bulgarian Institute for Standardization - Website Canada - SCC - Standards Council of Canada - Website Canada - CSA - Canadian Standards Association - Website Chile - INN - Instituto Nacional de Normalizacion - Website China - SAC - Standardization Administration of China - Website China - CSSN - China Standards Information Center - Website Colombia - ICONTEC - Instituto Colombiano de Normas Técnicas y Certificación - Website Costa Rica - INTECO - Instituto de Normas Técnicas de Costa Rica - Website Croatia - DZNM - State Office for Standardization and Metrology - Website Cuba - NC - Oficina Nacional de Normalización - Website Czech Republic - CSNI - Czech Standards Institute - Website Denmark - DS - Dansk Standard - Website Ecuador - INEN - Instituto Ecuatoriano de Normalización - Website Egypt - EO - Egyptian Organization for Standardization and Quality Control - Website El Salvador - CONACYT - Consejo Nacional de Ciencia y Tecnología - Website Estonia - EVS - Eesti Standardikeskus - Website Ethiopia - QSAE - Quality and Standards Authority of Ethiopia Website Finland - SFS - Finnish Standards Association - Website France - AFNOR - Association française de normalisation - Website Germany - DIN - Deutsches Institut für Normung - Website and Deutsches Institut für Bautechnik Greece - ELOT - Hellenic Organization for Standardization - Website 7 Grenada - GDBS - Grenada Bureau of Standards - Website Guatemala - COGUANOR - Comisión Guatemalteca de Normas - Website Guyana - GNBS - Guyana National Bureau of Standards - Website Hong Kong - ITCHKSAR - Innovation and Technology Commission - Website Hungary - MSZT - Magyar Szabványügyi Testület - Website Iceland - IST - Icelandic Council for Standardization - Website IndiaBIS - Bureau of Indian Standards - Website Indonesia - BSN - Badan Standardisasi Nasional - Website Iran - ISIRI - Institute of Standards and Industrial Research of Iran - Website Ireland - NSAI - National Standards Authority of Ireland - Website Israel - SII - The Standards Institution of Israel - Website Italy - UNI - Ente Nazionale Italiano di Unificazione - Website Jamaica - BSJ - Bureau of Standards, Jamaica - Website Japan - JISC - Japan Industrial Standards Committee - Website Jordan - JISM - Jordan Institution for Standards and Metrology - Website Kazakstan - KAZMEMST - Committee for Standardization, Metrology and Certification - Website Kenya - KEBS - Kenya Bureau of Standards - Website Republic of Korea - KATS - Korean Agency for Technology and Standards - Website Kuwait - KOWSMD - Public Authority for Industry, Standards and Industrial Services Affairs - Website Kyrgyzstan - KYRGYZST - State Inspection for Standardization and Metrology - Website Latvia - LVS - Latvian Standard - Website Lebanon - LIBNOR - Lebanese Standards Institution - Website Lithuania - LST - Lithuanian Standards Board - Website Luxembourg - SEE - Service de l'Energie de l'Etat, Organisme Luxembourgeois de Normalisation - Website Malaysia - Department of Standards Malaysia - Website Malta - MSA - Malta Standards Authority - Website Mauritius - MSB - Mauritius Standards Bureau - Website Mexico - DGN - Dirección General de Normas - Website Moldova - MOLDST - Department of Standardization and Metrology - Website Morocco - SNIMA - Service de Normalisation Industrielle Marocaine - Website Netherlands - NEN - Nederlandse Norm, maintained by the Nederlands Normalisatie Instituut (NNI) - Website New Zealand - SNZ - Standards New Zealand - Website Nicaragua - DTNM - Dirección de Tecnología, Normalización y Metrología - Website Nigeria - SON - Standards Organisation of Nigeria - Website Norway - SN - Standards Norway (Standard Norge) - Website Oman - DGSM - Directorate General for Specifications and Measurements - Website Pakistan - PSQCA - Pakistan Standards and Quality Control Authority - Website Palestine - PSI - Palestine Standards Institution - Website Panama - COPANIT - Comisión Panameña de Normas Industriales y Técnicas - Website Papua New Guinea - NISIT - National Institute of Standards and Industrial Technology - Website Peru - INDECOPI - Instituto Nacional de Defensa de la Competencia y de la Protección de la Propiedad Intellectual - Website Philippines - BPS - Bureau of Product Standards - Website Poland - PKN - Polish Committee for Standardization - Website Portugal - IPQ - Instituto Português da Qualidade - Website Romania - ASRO - Asociatia de Standardizare din România - Website Russian Federation - Rostekhregulirovaniye - Federal Agency for Technical Regulation and Metrology - Website Saint Lucia - SLBS - Saint Lucia Bureau of Standards - Website Saudi Arabia - SASO - Saudi Arabian Standards Organization - Website Serbia and Montenegro - ISSM -Institution for Standardization of Serbia and Montenegro - Website Seychelles - SBS - Seychelles Bureau of Standards - Website Singapore - SPRING SG - Standards, Productivity and Innovation Board - Website Slovakia - SUTN - Slovak Standards Institute - Website Slovenia - SIST - Slovenian Institute for Standardization - Website South Africa - SABS - South African Bureau of Standards - Website Spain - AENOR - Asociación Española de Normalización y Certificación - Website Sri Lanka - SLSI - Sri Lanka Standards Institution - Website Sweden - SIS - Swedish Standards Institute - Website Switzerland - SNV - Swiss Association for Standardization - Website Syrian Arab Republic - SASMO - The Syrian Arab Organization for Standardization and Metrology - Website 8 Taiwan (Republic of China) - BSMI - The Bureau of Standards, Metrology and Inspection - Website Tanzania - TBS - Tanzania Bureau of Standards Thailand - TISI - Thai Industrial Standards Institute - Website Trinidad and Tobago - TTBS - Trinidad and Tobago Bureau of Standards - Website Turkey - TSE - Türk Standardlari Enstitüsü - Website Uganda - UNBS - Uganda National Bureau of Standards - Website Ukraine - DSSU - State Committee for Technical Regulation and Consumer Policy of Ukraine - Website United Kingdom - BSI - British Standards Institution aka BSI Group - Website United States of America - ANSI - American National Standards Institute - Website Uruguay - UNIT - Instituto Uruguayo de Normas Técnicas - Website Venezuela - FONDONORMA - Fondo para la Normalización y Certificación de la Calidad - Website Vietnam - TCVN - Directorate for Standards and Quality - Website 1.5.4 Slovak Standards Institute Slovak Standards Institute (SUTN) has been established on 1st January 1993 by the Slovak Office of Standards, Metrology and Testing (UNMS). Since 1st January 1999 it has become a state contributory organization with its own budget, approved by the UNMS yearly. Since 1st January 2000 according to § 6 clause 2 of the Act No 264/1999 Coll. On the technical requirements on products and conformity assessment and on change and amendment of some acts the UNMS President authorized SUTN as the only legal body designated for development, approval and publishing of Slovak Standards, fulfillment of obligations following from international contracts and from the membership in International and European standards organizations (ISO, IEC, CEN, CENELEC and ETSI). This act provided for SUTN being the National standardization body (NSB). Every year SUTN and UNMS conclude a contract on development, approval and publishing of Slovak Standards, international cooperation and fulfillment of other duties arising from the NSB Status with determined government contribution for providing standardization activities in state interest. The current activities of SUTN cover: • • • • elaboration of Slovak standards; publishing and distribution of Slovak standards and other documents related to standardization; fulfillment of the National information center functions (NIS); fulfillment of the National standardization body functions (NSB). In detail, SUTN is engaged in following activities: • • • setting up and providing methodological control over the standardization plan; providing groundwork for approval of STN drafts (including amendments) and proposals for withdrawal of valid STNs; keeping records of approved STNs, their amendments and withdrawals; preparing groundwork for publishing in „Vestník UNMS SR“; 9 • • • • • • • • • • • • establishing Technical Committees (abbr. TK) and operating according to TK Statutes; setting up methodological standardization guides; working out statements or giving opinions concerning legal regulations, or other documents laying out the standardization activities in Slovakia; participating at the meetings of international and European standardisation organisation to the extent of its authorization; setting up and administer STN collections and STN archive; setting up and administer collections of European, International and foreign standards, regulations and publications related to standardization; setting and administer the Slovak standardization information system; publishing of STNs, Catalogues and other publications including periodicals (The UNMS Journal, magazines Standardization, Metrology and testing); publishing electronic products; providing data retrieval from databases; providing information and consultations about standardization; organising educational courses and training for external participants. The main focus of SUTN today is to ensure the complete harmonization of national collection of standards through implementation of European standards and supporting an involvement in development of European standards. Cooperation with International, European and foreign standard organizations SUTN as the National Standardization Organization (NSO) is the member of: • • • • International Orgaization for Standardization (ISO), International Electrotechnical Commission (IEC), European Committee for Standardization (CEN), European Committee for Electrotechnical Standardization (CENELEC). and performs the tasks of National standardization organization in The European Telecommunications Standards Institute (ETSI). The main goal of these organizations is by development of voluntary International and European standards to contribute to removal of technical barriers for trading. SUTN through experts, members of National Technical Committees comment the drafts of International and European standards. SUTN became the national member of CEN on 1st January 2003 and National member of CENELEC on 5th June 2002. Fulfilment of duties linked to the membership became the priority of SUTN. 10 STN Standards and national TCs Slovak Standards Institute (SUTN) is the only legal body designated to elaboration, approval and publishing of Slovak Standards (STN) according to the decision No. 1/2000 of the President of Slovak Office of Standards, Metrology and Testing (UNMS) in compliance with the Act No. 264/1999 Coll. On technical requirements of products and on conformity assessment and on change and amendment of some acts as amended. This decision was published in unit 12 of the Collection as the Announcement No. 25/2002 Z. z. Slovak standards are developed and approved in accordance with § 6 of the Law No. 264/1999 Coll. and marked with STN symbol. Currently the system of Slovak national standards contains 28 808 valid standards. The distribution of them according their origin and according the sectors are given in the following diagrams: Marking of the Standards Marking of Interantional (ISO, IEC), Regional (EN) Standards These standards are consecutive numbered according to time sequence approving. Number of the standard is sequential number and this number not market appropriate technical department. Example of standard marking is following: 11 Marking of STN standards Till end of year 1992 was valid Czechoslovak state standards. After dividing Czechoslovak republic: - in Slovak republic was founded short cut STN („slovenská technická norma”) - in Czech republic was kept short cut ČSN („česká norma”). Initial standards ČSN are valid after year 1992 too, in Slovak republic are used with new marking “STN” (by the restamping), but with initial number (see following figure). 12 Example of standard marking is following: If standard STN takes over international standard (ISO, IEC) or regional standard (EN), marking of this standard is following: Example of European standard taken over by standard STN: This chapter was worked according to literature [1], [2], [6]. 13 2 PROTECTION OF INDUSTRIAL PROPERTIES Industrial property is a category of intellectual property, which includes types of intellectual property that are susceptible of industrial application. Industrial right refers to industrial property that is a result of creativity and intellectual activity, e.g. invention, technical solutions or external appearance of products - designs. Industrial rights cover also group of rights called as "rights to designation" such as designation of goods and services to improve its marketing quality. The second category of intellectual property is a copyright and related rights, which are subject to competence of Ministry of culture of the Slovak Republic. 2.1 Patents According to the Act No. 435/2001 Coll. on Patents, Supplementary Protection Certificates and on Amendment of Some Acts in wording of the Act No. 402/2002 Coll., patents shall be granted for inventions which are new, involve an inventive activity and are susceptible of industrial application after performing preliminary and substantive examination. The so-called deferred examination with publication of applications after expiry of 18 months is implemented. The full examination shall by carried out upon the request of an applicant, which shall be filed within 36 months as from the filing date of the patent application. It is also possible to patent chemical products and medicaments. The term of the validity of a patent is 20 years as from the filing date of the patent application. The prerequisite of the duration of the patent protection is the payment of maintenance fees. 2.2 Utility models Since 1992 it has been possible to protect as an utility models a technical solutions which are new, exceed the common technical skills and are susceptible of industrial application, under the Law No. 478/1992 Coll. on Utility Models. The procedure is based on the so-called "registration principle". Only formal examination is carried out before the registration of a utility model into the Register. Contrary to the protection by a patent, neither process or production activities, nor biological reproductive material shall be protected by a utility model. The Law allows an applicant of a utility model to apply for the priority right from earlier utility model application . 14 The term of protection of a utility model is 4 years as from the filing date of the application and may be extended for a maximum of two three-year periods upon the request of the owner of a utility model. 2.3 Design Applications of designs must meet, according to Act No. 444/2002 Coll. on designs, formal and substantive requirements. Among the basic requirements for the registration of design into the Register and certification belong the novelty and specific character of design. Design shall mean the appearance of a whole or a part of a product resulting from the features of, in particular, the lines, contours, colours, shape, texture or materials of a product itself or its ornamentation; The validity of the registered design is five years from the date of filing the application of design. This period may be renewed by the owner of the registered design repeatedly for up to four periods of five years, up to a total term of 25 years from the date of filing the application. 2.4 Trademark The Act No 55/1997 Coll. on Trademarks as amended defines the conditions for the so-called registrability of a trademark. A trademark shall be verbal, figurative, threedimensional or combined denomination, which is capable of distinguishing goods and services of various manufacturers or suppliers of services. In addition, the Law specifies in detail exclusions of denominations from the Register as well as denominations that could not be a trademark. For example, it is the case of denominations having no distinctive nature, denominations containing the official names of States, denominations of goods and services kinds, generally known geographical denominations, deceptive denominations, denominations identical with a trademark registered in the name of another person, for the goods and services of the same kind. A legal entity or a natural person may file the application for the registration of a trademark. The term of protection of the registered trademark is 10 years as from the filing date of the application for a trademark. Upon the request of the owner of a trademark and after the payment of administrative fee the Office shall extend the term of protection by the renewal of the registration indefinitely by ten-year periods. This chapter was worked according to literature [7]. 15 3 TECHNICAL DRAWING An technical (engineering) drawing is a type of drawing that is technical in nature, used to fully and clearly define requirements for engineered items, and is usually created in accordance with standardized conventions for layout, nomenclature, interpretation, appearance (such as typefaces and line styles), size, etc. Its purpose is to accurately and unambiguously capture all the geometric features of a product or a component. The end goal of an engineering drawing is to convey all the required information that will allow a manufacturer to produce that component. Drawings convey the following critical information: • Geometry – the shape of the object; represented as views; how the object will look when it is viewed from various standard directions, such as front, top, side, etc. • Dimensions – the size of the object is captured in accepted units. • Tolerances – the allowable variations for each dimension. • Material – represents what the item is made of. • Finish – specifies the surface quality of the item, functional or cosmetic. For example, a mass-marketed product usually requires a much higher surface quality than, say, a component that goes inside industrial machinery. 3.1 Lines on the engineering drawing When we draw a technical drawing, we have the main problem: to represent a three dimensional real object into a two-dimensional area - pictures in the drawing. The representation must by readable and understandable. The object shape, object dimensions and all other details must clearly be seen. A very important component for drawing an understandable representation is the usage of the different line types. 3.1.1 Lines styles and types Lines on drawings are distinguished: 1) by the thickness a) thin line b) thick line c) very thick line 16 2) by the type a) solid line (continuous line) b) dashed line c) dot and dash line (centreline) d) dot and dash line with two dots e) dotted line f) irregular line: free hand line g) zig-zag precise line The standardized thicknesses of the lines for technical drawings are: 0.18, 0.25, 0.35, 0.5, 0.7, 1.0, 1.4 and 2.0 mm. The recommended thicknesses of the lines on drawings in mm are sorted in the following line groups: Line groups Thin line 0.5 0.7 1.0 0.25 0.35 0.5 Thick line 0.5 0.7 1.0 Very thick line 1.0 1.4 2.0 It is useful to keep a bigger difference of line thickness, than recommended, for a good looking drawing. 17 3.1.2 The usage of the lines in the drawings Line type Thin continuous Thick continuous Very thick continuous Thin irregular Thin dashed Thin dot and dash Thin dot and dash with two dots Thin dotted Usage in standard technical drawing Usage in electrical connection drawings (diagrams) - circuit diagrams generally - dimension lines, extension lines, leaders, - auxiliary circuits if they are dimension arrowheads distinguished from main circuits - hatching lines - depth of the threads - - transformers and electrical - visible rounded edges machines sheet orientation - indeterminate edges and intersections - flat surface diagonals - future bend lines on the developed view of bend detail - area of non-drawn repeated detail's - geared wheel root circles - visible edges, contour lines and sharp - main circuits and function intersections in views and section views connections if they are - arrowheads for section plane marking distinguished from auxiliary - thread ends circuits - soldered joints - cable forms - glued joints - bunched cables - interruption of views - interruption of broken-out sections, etc. - shielding - non-electrical connections - hidden contour lines and edges (mechanical, hydraulic, etc.) - mark out the boundary of devices or components group - axis and centre lines - separation between field of - pitch lines and pitch circles electrical control panels - for earth conductors - end positions of the moving parts - representation of the original shape or final shape - edges and contour lines of adjacent objects - axis of the centre of gravity - details in front of projection plane - continuation or repeating of the same - continuation or repeating of the parts on drawing same components or circuits 18 Examples of different lines in a technical drawing: a) in a standard technical drawing: - Thick continuous lines - visible edges, contour lines, sharp intersections in a screw view and in a hole section view, thread ends. - Thin continuous lines - hatching lines, depth of threads lines, run out lines. - Thin dot and dash line - screw and hole axes (centre line). b) In a electrical connection drawing (circuit diagram): Level of circuit function is distinguished by: - Thick continuous lines - main circuit - electric motor supply. - Thin continuous lines - auxiliary circuit, motor switching and direction control. - Thin dashed line - mechanical, non-electrical, connection of main three-phase switch contacts and push button contacts. This chapter was worked according to literature [3]. 19 3.2 Drawing to Scale When the object is drawn in its actual size, we say that the drawing is drawn to full-scale or drawn to the scale 1: 1. Many objects, however, including big electro motors, generators in power plants, transformers, antenna masts, towers of broadcast and television transmitters, radar aerials etc., are too large to be drawn in full-scale. Therefore, they must be drawn to a reduced scale. An example may be a drawing of a radar aerial drawn to the scale 1 :50, for example. Pictures in the drawing are fifty-times smaller than the radar aerial. For similar reasons, small parts of measuring apparatus, switches, push buttons, masks of integrated circuits and similar objects must be drawn larger than their actual size, in order to clearly define their shapes. These drawings are drawn to the enlarged scale. For example a contact of a small switch, could be drawn to the scale 10:1. Pictures in the drawing are ten times bigger than the contact. Standardised scales: • Basic scale (full scale) -1:1. • Enlarged scale - 2:1,5:1, 10:1,20:1,50:1, 100:1, .. , • Reduced scale - l:2, 1:5, 1:10, 1:20, 1:50, 1:100, 1:200, 1:500, ... The appropriate choice of the scale is very important for the readability of the technical drawing. More drawing scales may be used on one drawing. All principal views and the majority of the other views must be drawn in the basic scale. But if there were some small parts on the object, they would not be readable. Such parts may be drawn in the enlarged partial views. These pictures must not be conjugated to the principal views and we must designate them as detail (for example Z), and we must accomplish such a picture by a ratio of a scale, for example 5:1 – see following figure. 20 3.3 Lettering of the Drawings There are many texts in the drawing. There are dimension figures, some descriptions, prescribing of surface roughness and special surface treatment, etc. Several texts are written into the comer title as well. All these texts must by clear and completely readable without any danger of misunderstanding. This is the main reason for using uniform lettering in technical documentation, especially for lettering of drawings. Lettering, for technical drawings, is defined as two dimensions of width: - Slim letters are designated as letters of type A (d/h = 1/14) - Wide letters are designated as letters of type B (d/h = 1/10) Letters of type B are used for general use for technical documentation lettering. The lettering, for technical drawings is defined as two inclinations: - vertical letters, which are also widely preferred, - letters inclined by 75°. Inclined letters are not used in official presentation of technical documentation and we must not use them. The Standards define the basic heights of capital letters. We must only use standardised values, which are: 1,8 – 2,5 – 3,5 – 5 – 7 – 10 – 14 – 20 mm 21 3.4 Standard paper sizes, position of standard sheets In the ISO paper size system, the height-to-width ratio of all pages is the square root of two (1.4142 : 1). ISO 216 defines the A series of paper sizes based on these simple principles: • The height divided by the width of all formats is the square root of two (1.4142). • Format A0 has an area of one square meter. • • Format A1 is A0 cut into two equal pieces. All smaller A series formats are defined in the same way. If you cut format An parallel to its shorter side into two equal pieces of paper, these will have format A(n+1). • The standardized height and width of the paper formats is a rounded number of millimeters. Standard sheets are used for 99% of ordinary drawings. We define complementary extended standard sheets and special extended standard sheets for a drawing of a very long subjects or very tall subjects. All of the extended sheets come from the standard sheets by multiplying their shorter side. 22 The basic positions of the standard sheets are shown on the picture. All drawings except for A4 must be drawn in the horizontal position. Only A4 sheets must be drawn in the vertical position. The Standards allow us to draw in a different drawing position, but only if it is really necessary - for drawings of very tall and slim antenna masts, towers of broadcast and television transmitters, etc. Exceptionally in this case, we may use the standard sheets vertically. This chapter was worked according to literature [1], [2], [6]. 23 4 ORTHOGRAPHIC PROJECTION The main problem of technical documentation is that we want to transform a threedimensional real object into a two-dimensional area – our drawing. One of the kinds of these transformations is orthographic projection. "Orthographic" comes from the Greek word for "straight writing (or drawing)." This projection shows the object as it looks from the front, right, left, top, bottom, or back, and are typically positioned relative to each other according to the rules of either first-angle or third-angle projection. First angle projection (ISO-E method) is the ISO standard and is primarily used in Europe. Symbol: In first-angle projection, the object is conceptually located in quadrant I, i.e. it floats above and before the viewing planes, the planes are opaque, and each view is pushed through the object onto the plane furthest from it. (Mnemonic: an "actor on a stage".) Extending to the 6-sided box, each view of the object is projected in the direction (sense) of sight of the object, onto the (opaque) interior walls of the box; that is, each view of the object is drawn on the opposite side of the box. A two-dimensional representation of the object is then created by "unfolding" the box, to view all of the interior walls: This produces two plan views and four side views: 24 Third angle projection (ISO-A method) is primarily used in America. Symbol: In third-angle projection, the object is conceptually located in quadrant III, i.e. it lurks below and behind the viewing planes, the planes are transparent, and each view is pulled onto the plane closest to it. Using the 6-sided viewing box, each view of the object is projected opposite to the direction (sense) of sight, onto the (transparent) exterior walls of the box; that is, each view of the object is drawn on the same side of the box. The box is then unfolded to view all of its exterior walls. Here is the construction of third angle projections of the same object as above. Note that the individual views are the same, just arranged differently. 25 Examples: This chapter was worked according to literature [3], [8]. 26 5 BASIC RULES FOR DIMENSIONING Dimensioning is the determination of the object size and of the object shape location. In general, the descriptions of the shape and of the size give complete information for production of the object represented by the drawing. We should follow certain standards, rules and practices on our drawing. The basic dimension system consists of: - dimension line, - two extension lines, - two internal or two external arrowheads, - dimension (numerical value). Basic kinds of dimensioning are: - Dimensioning of lengths and distances between point's lines or planes - Dimensional of radii - Dimensioning of diameters 27 - Dimensioning of angles We will demonstrate basic rules for dimensioning on the following picture where a simple completely flat detail is drawn and dimensioned. Most kinds of dimensioning are shown in this picture. Three basic detail dimensions must always be dimensioned. This mean the maximum length (dimension 100), maximum height (dimension 52) and maximum depth (dimension T2 thickness of 2 mm) of the detail must be dimensioned. The dimension line shows the extent of length, of width or of thickness to which the dimension is applied. The dimension line must always be parallel to the dimensioned size and it is always drawn by a thin continuous line. The dimension line is terminated by two arrowheads, which touch the insides of the extension lines, if there is enough place. If arrowheads are drawn inside (dimensions 100, 52, 50, 49, etc.), the dimension line must not overdraw the extension lines. The arrowheads are drawn outside if there is not enough place. The dimension line is drawn about 2 mm beyond the external arrowheads (dimensions 6, 5, 4, etc.). The 28 spacing between the border of a view and the first dimension line is 12 mm to 15 mm (for the height of the dimension figure is 3.5 mm to 5 mm). The spacing between other dimension lines are 10 mm to 12 mm. The spacing must be kept the same on the whole drawing. Dimension line must not continue from contour lines, axes, extension lines, etc.! The dimension figure (or we may say only the dimension) is a numerical value expressed in mm, written in the middle of the dimension line about 1 mm above the dimension line (dimension 100, 52, 50, 49, 25, 8, 3, etc.), if there is enough place. If there is not enough place, we may write the dimension outside of the dimensioning space, above the extended dimension line (dimension 4 and ∅8). Usually, dimensions are drawn outside of the view. However, if extension lines would be too long for some inner dimension, and if there is enough place, we may locate the dimension inside the picture (dimension 14, 7 and radius R12). Ifwe are dimensioning the position of an element or of an element group and their inner sizes, which belong together, we draw dimension lines on one line (dimension 49 which determines the distances between holes and dimension 25 which determines the position of the group of these two holes on the detail). If one adjacent dimension is small in this case and if its arrowheads are drawn outside, we may use inner arrowhead for both dimensions (3 mm groove and its position 50 mm). One exception exists only: when dimensioning a curve from point to point. For dimensioning such objects, by sufficient density, we may draw the dimension lines on the same line as the extension lines. The extension lines serve satisfactorily for positioning of the dimension lines. Extension lines are used to indicate the locations, such as points or surfaces, between which the dimension is applied. Generally, they begin from the comers or limits 29 of the dimensioned parts. They may continue from the ends of the axes too. Extension lines are always drawn by a continuous thin line and they extend about 2 mm beyond the outermost dimension line. Extension lines must be parallel to each other. They are perpendicular to the dimension line in most cases. Exceptionally, if extension lines come too close to contour lines, we may draw oblique extension lines, but again, they must be parallel to each other. Some very important rules are: • Dimension lines must not cross each other. • Dimension lines and extension lines must not cross each other, if possible. • Extension lines may cross and they usually cross each other. The next rule follows from these rules: We must draw longer dimensions farther away from the picture and shorter dimensions closer to the picture (dimensions 52, 21 and 5 on the left side of the picture, 100, and 50 on the top, and 24 and 4 on the right side). If we do not accept this rule, then the dimension lines and extension lines will cross. That is a great mistake! 30 The arrowheads terminate the dimension line and determine the dimensioned size. They must touch the extension lines by its tips exactly. Arrowheads must have the same shape and size on the whole drawing. Arrowheads may be drawn by a template for uniformity. Usually, designers draw the arrowheads by hand without a template. Freehand arrows should be drawn carefully to really make them the same all over the drawing and to be readable. The angle between the arms of the preferred arrowheads in Europe is approximately 20°. The recommended length of arms is 3.5 mm to 5 mm (minimum 2.5 mm). The area between the arms may be filled, only if the arrowheads are drawn by Indian ink. If there is not enough space between the extension lines and if we are not able to draw arrowheads there, we may use about a 5 mm long short oblique line at an angle of 45° instead of an inner arrowhead exceptionally (between dimensions 6 and 3 in the picture below). If there are several short dimensions, we may use more of these short oblique lines. However, there must be two arrowheads drawn on the outside limits of these chain dimensions - two external arrowheads. This chapter was worked according to literature [1], [2]. 31 6 ELECTRICAL DIAGRAMS DRAWING A circuit diagram (also known as an electrical diagram, wiring diagram, elementary diagram, or electronic schematic) is a simplified conventional pictorial representation of an electrical circuit. It shows the components of the circuit as simplified standard symbols, and the power and signal connections between the devices. 6.1 Graphical symbols for diagrams International standards for graphical symbols is IEC 60617. IEC 60617 contains graphical symbols for use in electrotechnical diagrams. IEC 60617 contains some 1750 graphical symbols. IEC 60617 originally consisted of 13 parts, from resistors and capacitors to logic symbols and even a generalised drawing standard of connections and bus line widths. 6.1.1 Parts of IEC 60617 — Part 1: General information, general index. Cross-reference tables; — Part 2: Symbol elements, qualifying symbols and other symbols having general application; — Part 3: Conductors and connecting devices; — Part 4: Basic passive components; — Part 5: Semiconductors and electron tubes; — Part 6: Production and conversion of electrical energy; — Part 7: Switchgear, controlgear and protective devices; — Part 8: Measuring instruments, lamps and signalling devices; — Part 9: Telecommunications: Switching and peripheral equipment; — Part 10: Telecommunications: Transmission; — Part 11: Architectural and topographical installation plans and diagrams; — Part 12: Binary logic elements; — Part 13: Analogue elements. 6.1.2 Parts of electronic component symbol General electronic component symbols are basic forms of schematic component symbols. They express the basic function of the electronic component; 32 for example: - rectifier diode - resistor A general component symbol may be completed by an additional symbol. The component function becomes precise by the additional symbol; for example: - nonionising radiation - variability The general component symbol supplemented with the additional component symbol gives us the detailed component symbol. The detailed component symbol represents complete component function; for example: - photodiode - variable resistor If the function of internal components are not important and we are interested in the final total complete function only, we may use a block electronic symbol; 33 for example: Electronic component symbols are drawn horizontally or vertically in diagrams. We draw them in other positions only exceptionally (in measuring bridges, in rectifier bridges, in memory fields, for example). We draw them at the angle of 45° in these cases. 6.1.3 Representation of electronic components Some complex electrical or electronic components are completed from several basic electrical or electronic elements. A classic electro-mechanical relay is assembled from a coil of a relay (operating device) and from one or several contacts. The coil and contacts create one complex object. The complex component can be drawn in the following the representative ways: - Assembled representation - we draft component elements together if it is possible. In this representation the complex function is easily visible. We can clearly see that the relay coil moves the contacts in the picture. The mechanical bond is drafted by a thin dashed line as a non-electrical connection. - Decomposed representation - if it is not possible to draft the complex component elements together, if the electro technical diagram is very complicated or if the component elements are in other circuits, we draft the decomposed complex component. Contacts are drawn in another place of the diagram than the coil of the relay (see the 34 picture on the next page upper left). Every relay contact may be drawn in another place of the diagram. 6.1.4 Multi pole and single pole diagrams In heavy current electro technical diagrams, especially in three-phase lines and installations, the same devices are drafted three times. Sometimes, in generally used wirings and connections, we may simplify the heavy current diagrams by using a socalled single pole drafting. We draw every element of the diagram only once, and to be a three-phase diagram, we cross each element by three, short, parallel lines, at the approximate angle of 60°. We may use one short line at the angle of 60° and attach the figure 3 near them (the parallel lines). We can see a three-phase transformer in the picture. One winding is a starconnected winding (Y -connected winding) the second one is a delta connected winding. There is the three-phase transformer drafted by classic multi pole method on the left picture. It is drawn with all three-conductor wires on the primary (input side) and on the secondary (output side) as well. There is the same three-phase transformer drawn by the single pole method on the right picture. 35 6.1.5 Labelling of electrical and electronic components Code A Component Function blocks, assembly, sub-assembly (amplifiers, modulators, lasers, masers, electrical assembly on the printe d circuit boards - PCB) B Converters between non-electrical quantities and electrical ones (microphones, loudspeakers, position sensors, piezoelectric transducers, selsyns, thermocouples, photo-electric cells, etc.) C Capacitors D Digital components and devices, delay devices, memory banks (logical, numerical, binary circuits, delay lines) E Varied components, details and function units (heaters, lights, freezing devices) F Safety and protective devices (fuses, breakdown switches, arresters) G Energy, signal and feeding sources (generators, batteries, oscillators) H Signalling devices (bells, horns, light indicators) K Switches controlled by electric current (relays, contacts) L Inductivities, reactors and chokes (inductive coils, end chokes) M Motors, servomotors N Analogue elements and units (analogue circuits, operating amplifiers) P Measuring instruments, testing devices (timers, integrative instruments) Q Switches for power circuits (switches, disconnecters) R Resistors (potentiometers, rheostats, thermistors) S Switches in communication and auxiliary circuits (conductors, push-buttons, controllers, limit and end switches) T Transformers (voltage and current) U Converters between electrical variables (optic-couplers, modulating components, modulators, demodulators, encoders, converters, frequency converters) V Electro-vacuum and semiconductor details (electron tubes, cathode-ray tubes, discharge lamp/tubes, transistors, diodes, thyristors) 36 6.1.6 Types of electro-technical diagrams Electro-technical diagrams can be divided into following groups: a) diagrams for general information about devices - they are elaborate in the phase of the projection of electrical devices - arrangement of the components interconnections on the diagram does not correspond to their physical locations in the finished device - they present main relations between main components inside of the system - they are drawn by the one-pole drawing Here belong: Survey diagrams Block diagrams - example of block diagram of an audio amplifier system Teaching diagrams - acts to explain the function of the equipment. All devices do not have to be drawn there. Only those that describe function can be seen on them. b) diagrams for determination of devices composition - they present all components of devices and connection between them - arrangement of the components interconnections on the diagram does not correspond to their physical locations in the finished device 37 Here belong: Circuit diagram (electronic circuit) - serves a complete description of the equipment, detailed clearing up of its function for its construction, analysis and computation. Main circuit diagram - is drawn by thick lines in a heavy current circuit diagram. We can see this part in the threephase electric motor supply on the following picture. The single pole diagram of the main circuit diagram of the three-phase electric motor supply is shown on following picture. 38 Auxiliary circuit diagram - is drawn by thin lines in a heavy current circuit diagram. Circuit diagram for repairing - contains basic circuit diagram with added important data of voltage in some points, for example. If the voltage has a variable behaviour – an irregular waveform for instance, the circuit for repairing contains pictures with prescribed real time behaviour. Serviceman may take it visible on the cathode-ray oscilloscope, for example. Substitution diagram - serves for computation of devices. The substitution diagram allows us to describe equipment by the simplest equations combination. 39 c) realisation diagrams - arrangement of the components interconnections on the diagram does not correspond to their physical locations in the finished device Wiring diagram of internal connections - shows the internal connections of devices and their terminals. Example is in the following picture. Note: The control panel and push-button switchboard is closed in dot and dash frames. Wiring diagram of external connections - shows the external connections between device terminals (lines between the dot and dash frames in the picture) Situational diagrams - show the electric wire distribution system and machine, device and equipment real arrangement in a factory, in flats or in other spaces. Following figures illustrate „House wiring situation diagram“ and „Electrical cable network 0,4 kV situation diagram“. 40 This chapter was worked according to literature [1], [4], [9]. 41 7 TECHNICAL DOCUMENTATION FOR PRINTED CIRCUIT BOARD A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, or traces, etched from copper sheets laminated onto a non-conductive substrate. A printed circuit board (PCB) is a prefabricated conductive circuit pattern, reproduced on a thin sheet of insulating material. When it is assembled with electronic components, it becomes a complex electronic component. The printed circuit board usually mechanically holds and connects all required electrical components. The base of PCB, over which a thin layer of copper foil is bonded, it may be a paper base with phenol or epoxy resin, but today fibreglass base with epoxy resin is usually used. The thickness of board base is 0.5 mm to 3 mrn (usually 1 mm to 1.5 mm). The thin layer of metal foil bonded to the plastic base is usually copper. The thickness of this foil is about 40 µm. If the metal foil is only spread over the PCB on one side, the board is called a single-sided board. If the metal foil is spread over the board on both sides, it is called double-sided board. Boards also exist, where the copper foil is alternately sandwiched among layers of plastic. Many layers of plastic with copper circuitry are filled together to produce a board with extremely complex circuitry. These type of boards are called multilayer boards. They are used for example for computer main boards, for professional TV signal amplifiers etc. Example of PCB: 42 7.1 Main kinds of PCB The main kinds of PCB patterns are: a system of uniform gaps, a system of functional areas and a system of uniform conductors. System of uniform gaps - is not usually used professionally. There is a danger of shortcircuits and there may be large capacity between conductors for some high-frequency circuits. This system is usually used in amateur applications, because the gaps may be easily scratched-out with a saw blade. System of functional areas - was often used for consumer electronics, as in radio receivers, TV sets, video recorders, etc. 43 System of uniform conductors - is used for precise industrial electronics, computers, etc. Nowadays, it is widely used for all electronic constructions, professional and consumer as well. 7.2 Classes of PCB Classes of PCB are characterised by the following parameters in a system of uniform conductors: minimal distance between the centres of two adjacent holes, minimal size of soldering flats, minimal width of conductors and minimal width of isolated gaps. 44 7.3 Complete documentation for manufacturing of PCB - For a large-volume production of PCB the following documentation is used: Resulting board drawing Sample and drawing of conductor pattern Sample and drawing of standard holes Special holes drawing Sample of non-soldered mask Sample of printing drawing Component location drawing Circuit diagram Electronic components list Mechanical components list Every final document must contain all particulars as they are represented in the example to the left: the resulting board drawing. Of the above-explained documentation only the main drawing parts will be shown in the following sections. 45 7.3.1 Sample and drawing of conductor pattern The side of the PCB for soldering is designated as side A. Side B is used for assembling components. The sample and drawing of the conductor pattern for side B is drawn for a double-sided printed circuit board only. The sample and drawing of conductor pattern must contain: - conductor pattern, - marking of centres of standard holes - these are the holes for leads of electronic components. - marking of special holes - if there are some. These are big cylindrical holes, square and rectangular holes for coils, transformers, coolers etc. - designation of PCB - the name of circuit, product number and designation of producer - marking of the PCB contour by corner symbols - there must not be a continuous contour line around the printed circuit board used, because a short circuit may arise there. We may use a thin dashed line if we need to show complicated contour line - Two checking points - Checking size between centres of checking points - serves for precise enlargement, if the pattern of the PCB is realised by photomethods - Two inserting points - serve for precise positioning of the motif of the T PCB pattern and all other drawings to the same position on the semi- product - copper plated board. - Starting point - serves as a starting point for manufacturing, for precise standard hole drilling by a numerically controlled drilling machine, etc. 46 7.3.2 Sample and drawing of standard holes The sample and drawing of standard holes serves for drilling of standard holes, which are holes for component wire terminals. The sample and drawing of standard holes must contain: - Locations of the standard holes centres with resolution of their diameters. - Marking of the PCB contour by corner symbols. - Checking size and checking, inserting and starting points . - Numbers of holes for different diameters. 7.3.3 Drawing of special holes If there are some special holes, the complete set of documentation of the PCB must contain the drawing of special holes. These are not ordinary cylindrical holes, special holes and slots for connectors, transformers, coils, coolers, etc. Drawing of special holes must contain: - Location, shapes and dimensions of special holes, - Marking of the PCB contour, - Inserting and starting points. 47 7.3.4 Sample of non-soldered mask The non-soldered mask protects PCB areas against the soldering where it is not necessary. It saves tin and protects the PCB against any damages from overheating. The non-soldered mask protects the PCB copper layer from corrosion during the working life of the device. The sample of non-soldered mask must contain: - Negative pattern of the non-soldered mask. - Checking size between centres of checking points. - Marking of the PCB contour. - Designation of the PCB and of the sample of the non-soldered mask 48 7.3.5 Sample of printing The sample of printing serves for printing of identification marks for electronic components - transistors, resistors, capacitors, integrated circuits, etc. and other information about the PCB. The sample of printing must contain: - Positive drawing of the printing. - Checking size between the centres of checking points. - Marking of the PCB contour. - Designation of the PCB and of the sample of printing. 7.3.6 Component location drawing of PCB The component location drawing of the PCB serves for layout construction of the PCB and for PCB assembling, checking and measuring. Drawing of the assembled printed circuit board is drawn onto transparent material, on tracing paper usually, as the view from the side of the electronic components. The conductor pattern may be drawn onto the second side, to show how the electronic components are connected. Electronic components must be drawn in their actual shape, actual position and actual dimension. It is important for fixing the location of components and keeping their relative positioning, the minimal distances and other construction rules. All electronic and mechanical components (the connectors, coolers, etc.) must be drawn on the drawing of the assembled printed circuit board. 49 Electronic components, which are not symmetrical, must be drawn with their orientation by their keys or markers. This is important especially for integrated circuits, transistors, diodes, electrolytic capacitors, etc. 7.3.7 Circuit diagram A circuit diagram is a schematic diagram of an electronic circuit, which shows the function of the circuit components by use of graphical symbols. 50 The list of electronic components must contain: - Component name (item). Component marking in drawings. Component value. Component type (model). Number of the same components in the same function in one PCB product. This chapter was worked according to literature [1], [3], [6]. 51 REFERENCES [1] Novák, F., Linkeová, I.: Technical documentation. Vydavatelství ČVUT 2004, Praha, ISBN 80-01-03040-7 [2] Veselovský, J.: Úvod do inžinierstva a technická dokumentácia. FEI STU Bratislava, 2006 [3] Šťastný, J. a kol.: Manuál technické dokumentace. Koop, České Budějovice, 1998 [4] Ďurovský, F., Seman, S.: Technická dokumentácia v elektrotechnike. MercurySmékal Košice, 2001 [5] http://www.sutn.gov.sk [6] http://en.wikipedia.org [7] http://www.upv.sk [8] Häberle, G. a kol.: Elektrotechnické tabulky pro školu i praxi. Europa-Sabotáles cz. Praha, 2006. ISBN 80-86706-16-8 [9] Veselovský, J., Kroupa, M.: Základy tvorby technickej dokumentácie v elektrotechnike. ALFA Bratislava, 1989. 52
