Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

NEG-IN

IEC

IEC logic negation at input

The negation circle at an input means that the external 0 state produces the internal 1 state of the element. It is a pure logic statement: to relate it to voltage levels, the drawing must declare positive or negative logic. TI's public overview notes that this is the older form, with the polarity triangle now preferred in device data books.

Drawing use

Schematic

Application

Logic & signals

Reference family

IEC / Manufacturer

Form evidence

Small circle at the input edge of the outline. Qualifying-symbol and dependency conventions as explained in TI's public overview of IEEE Std 91-1984, which incorporates IEC 617-12 work. Independent educational drawing; not certified IEC geometry or an IEC database identifier.

A distinction that matters

The polarity indicator triangle states an active-low level directly and does not depend on a declared logic convention.

Full referenceAdd to legend

NEG-OUT

IEC

IEC logic negation at output

Output negation turns AND into NAND, OR into NOR and a buffer into an inverter. The circle sits where the output line meets the outline and states that the internal 1 state produces the external 0 state. As with input negation, a logic convention must be declared to relate this to voltage levels.

Drawing use

Schematic

Application

Logic & signals

Reference family

IEC / Manufacturer

Form evidence

Small circle at the output edge of the outline. Qualifying-symbol and dependency conventions as explained in TI's public overview of IEEE Std 91-1984, which incorporates IEC 617-12 work. Independent educational drawing; not certified IEC geometry or an IEC database identifier.

A distinction that matters

An active-low output triangle states the level directly and is the data-book alternative.

Full referenceAdd to legend

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.