In the past I have seen two different symbols for a zener diode. One shows the complete "Z" shape on the cathode, and one shows more of an "L" shape on the cathode (see images below):
What is the difference between these? Do they actually have different meanings, or are they two ways of showing the same thing? Perhaps one is European and one is American? I always thought that they were simply two ways of showing the same thing, but a coworker of mine questioned it and now I am looking for confirmation.
Best Answer
The base symbol I can fine no definite standard reference for. I'd guess the majority of us would use it.
simulate this circuit – Schematic created using CircuitLab
Graphical samples for the Australian Standard AS 1102 (1989) Graphical symbols for electrotechnical does appear to reference this symbol. I don't have a copy, so I cannot confirm this.
Europe: International Electrotechnical Commission IEC60617 (2012) Graphical Symbols for Diagrams provide the following:
with the IEC60617 (1996) version defining the bars.
for:
Their usage of straight bars (05-02-04) is for Bi-directional or breakdown diode.
US: IEEE 315 (1975) Standard for Graphic Symbols for Electrical and Electronics Diagrams provides the straight bar symbol:
ANSI Y32.2 (1975) Graphic Symbols for Electrical and Electronics Diagrams has been superseded by IEEE315. It references the same symbol as IEEE315.