What ⎑ means
It marks a logic output whose built-in path holds the signal low.
That path lets it join a distributed connection, where circuit blocks share a line, without an extra component. Font outlines may vary.
IEC’s 1995 set for electrical-engineering documents included the entry; a 2000 report mapped it to ISO/IEC 10646, a larger text-character set. IEC’s database lists 2004-09-01 as the standardized circuit mark’s release date.
Specialist circuit notation for logic diagrams and electronics documents.
It labels an output; it is not a generic “down” signal.
Don't confuse it with
1Questions people ask
1Why does ⎑ show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type ⎑
⎑\2391Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.