Side-by-side reference

Understand the difference.

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

First referenceCompare with

IEC

IEC enable input (EN)

An input labelled EN inside the outline enables every external output of the element. At its internal 0 state, open-circuit outputs are off, three-state outputs go to high impedance and other outputs take their internal 0 state. It has no effect on inputs, according to TI's public summary of the notation.

Drawing use: Schematic
Application: Logic & signals
Reference family: IEC / Manufacturer
Form evidence: Input labelled EN inside 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

A C (control) input permits action of affected inputs; EN acts on outputs.

Full reference

IEC

IEC three-state output qualifier

The three-state qualifier is a small triangle pointing downwards, drawn inside the outline next to the output. It says the output has a third, high-impedance state in addition to high and low. The output is controlled by an EN input or by EN dependency.

Drawing use: Schematic
Application: Logic & signals
Reference family: IEC / Manufacturer
Form evidence: Small downward-pointing triangle inside the outline at the output. 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 open-circuit diamond indicates a stage that is off in one level, not a controlled high-impedance state.

Full reference

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