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
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)