April 1955 Popular Electronics
Table of Contents
Wax nostalgic about and learn from the history of early electronics. See articles
published October 1954 - April 1985. All copyrights are hereby acknowledged.
Electronics symbols for schematics and wiring diagrams have remained amazingly consistent for the last hundred years, although obviously many new ones have been added. You can see from this set of standardized wiring diagram and schematic symbols from a 1955 edition of Popular Electronics what I mean. Even symbols for newly introduced devices tend not to change. There are some variations such as whether or not to draw a circle around a transistor or how many lightning bolt lines to use with photon emitters and detectors, but that's about it. The digital world adopted IEEE Standard 91-1984 for logic and microprocessors, although you will still occasionally see variants in symbols, especially in early digital circuit schematics. The ARRL publishes its own version of standardized electrical schematic symbols, but even the ARRL Handbook, in which the symbols are printed, does not strictly conform to its own standards.
Standardized Wiring Diagram & Schematic Symbols
Wiring Diagram Schematic Symbols
Posted August 30, 2019 (original 3/25/2012)