Understand the difference.

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

CTR4

IEC

IEC synchronous binary counter (CTRm)

The general qualifier CTRm identifies a counter with m bits and a cycle length of 2 to the power m. In IEC form the clock appears as C with a + to show counting up, and load, clear and enable inputs use dependency notation such as M1 for load mode and G for count enable. Outputs carry binary weights 1, 2, 4 and 8.

Drawing use

Schematic

Application

Logic & signals

Reference family

IEC / Manufacturer

Form evidence

Rectangular element with CTRm qualifier, common-control block and weighted outputs. 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. The counterpart is the matching functional concept; no equivalence of every detailed standard graphic is asserted.

A distinction that matters

CTR DIVm states the cycle length directly and is used for non-binary counters such as decade counters.

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CTR-SYNC

Symbols

Synchronous binary counter

Updates its binary count from a common clock with the documented count-enable, load and clear controls.

Drawing use

Schematic

Application

Logic & signals

Reference family

Manufacturer

A distinction that matters

Synchronous operation does not remove setup/hold and output-delay requirements; reset can be synchronous or asynchronous depending on the part.

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