{"schemaVersion":1,"slug":"iec-decade-counter","name":"IEC decade counter (CTR DIV10)","kind":"symbol","abbreviation":"CTR DIV10","aliases":["BCD decade counter IEC form","divide-by-ten counter","CTRDIV10"],"category":"logic-signals","drawingTypes":["Schematic"],"referenceFamilies":["IEC","Manufacturer"],"summary":"IEC counter marked CTR DIV10, counting through ten states with BCD-weighted outputs.","description":["CTR DIVm identifies a counter whose cycle length is m. A decade counter is therefore CTR DIV10, with outputs weighted 1, 2, 4 and 8 for a BCD count from 0 to 9. The carry output is often marked CT=9 to show it is active at the last state.","Decade counters drive numeric displays through BCD-to-seven-segment decoders and form decimal dividers in timing circuits. A drafter cascading stages should show the CT=9 carry feeding the enable of the next decade.","This differs from a decoded one-of-ten counter, which provides ten separate outputs rather than a BCD code. Check the outputs before assuming either form."],"readingNotes":["DIV10 states a cycle of ten.","CT=9 marks the carry used to cascade decades."],"drawingChecklist":["Use CTR DIV10 rather than CTR4 for BCD counters.","Show BCD output weights.","Show cascading between decades."],"distinction":"The decoded decade counter has ten one-hot outputs rather than BCD-weighted outputs.","facts":[{"label":"Qualifier","value":"CTR DIV10"},{"label":"Outputs","value":"BCD weights 1, 2, 4, 8"},{"label":"Artwork scope","value":"Original educational illustration; consult the applicable standard and the selected device documentation for the exact graphic"}],"references":[{"sourceId":"s28-ti-ieee91-logic-symbols","relevance":"Defines CTR DIVm and contents outputs such as CT=9."}],"related":["one-hot-decade-counter","iec-bcd-to-seven-segment-decoder","iec-synchronous-binary-counter"],"artwork":"s28-iec-decade-counter","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","symbolVariant":{"convention":"IEC","form":"Rectangular element with the CTR DIVm qualifier, m = 10","reference":"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."},"plainEnglish":{"title":"What does IEC decade counter (CTR DIV10) mean?","introduction":"CTR DIVm identifies a counter whose cycle length is m. A decade counter is therefore CTR DIV10, with outputs weighted 1, 2, 4 and 8 for a BCD count from 0 to 9. The carry output is often marked CT=9 to show it is active at the last state.","example":"Decade counters drive numeric displays through BCD-to-seven-segment decoders and form decimal dividers in timing circuits. A drafter cascading stages should show the CT=9 carry feeding the enable of the next decade.","drawings":"This differs from a decoded one-of-ten counter, which provides ten separate outputs rather than a BCD code. Check the outputs before assuming either form.","terms":[{"name":"Signal","meaning":"Electrical information passed between devices, rather than necessarily the main power supply."},{"name":"Schematic","meaning":"A drawing showing function and connections rather than physical appearance."}],"diagram":"flow","steps":["Identify the device and form","Read the connections and state","Check the equipment reference"],"caption":"A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.","sources":[{"label":"Overview of IEEE Standard 91-1984: explanation of logic symbols (SDYZ001A)","url":"https://www.ti.com/lit/ml/sdyz001a/sdyz001a.pdf"}],"detail":"IEC counter marked CTR DIV10, counting through ten states with BCD-weighted outputs. The decoded decade counter has ten one-hot outputs rather than BCD-weighted outputs.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/iec-decade-counter","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/iec-decade-counter.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"s28-ti-ieee91-logic-symbols","title":"Overview of IEEE Standard 91-1984: explanation of logic symbols (SDYZ001A)","publisher":"Texas Instruments","url":"https://www.ti.com/lit/ml/sdyz001a/sdyz001a.pdf","type":"manufacturer","scope":"Public explanation of rectangular logic symbols, general qualifiers, input and output qualifiers, dependency notation, bistable elements and coders, consistent with IEC 617-12 work.","checkedOn":"2026-10-28","reuse":"link-only","relevance":"Defines CTR DIVm and contents outputs such as CT=9."}]}