DOE-HDBK-1016/1-93 ELECTRICAL DIAGRAMS AND SCHEMATICS Electrical Diagrams and Schematics Symbology To read and interpret electrical Figure 1   Basic Transformer Symbols diagrams  and  schematics,  the reader    must    first    be    well versed    in    what    the    many symbols     represent. This chapter discusses the  common symbols   used   to   depict   the many components in electrical systems.    Once  mastered,  this knowledge  should  enable  the reader to successfully understand most electrical diagrams and schematics. The  information  that  follows provides  details  on  the  basic symbols    used    to    represent components in electrical transmission, switching, control, and protection diagrams and schematics. Transformers The   basic   symbols   for   the various  types  of  transformers are shown  in Figure  1 (A).   Figure  1 (B)  shows how  the basic  symbol for  the transformer  is modified to represent specific types and transformer applications. In  addition  to  the  transformer Figure 2   Transformer Polarity symbol  itself,  polarity  marks are sometimes used to indicate current   flow   in   the   circuit. This  information  can  be  used to determine the phase relationship (polarity) between the input and output terminals of  a  transformer.    The  marks usually  appear   as  dots   on  a transformer  symbol,  as  shown in Figure 2. PR-03 Rev. 0 Page 2