{"schemaVersion":1,"slug":"npn-phototransistor","name":"NPN phototransistor","kind":"symbol","abbreviation":"PHOTO-NPN","aliases":["phototransistor","light-controlled transistor"],"category":"electronics-components","drawingTypes":["Schematic"],"referenceFamilies":["Manufacturer"],"summary":"An NPN transistor whose collector-emitter conduction responds to incident light in the documented detector arrangement.","description":["An NPN transistor whose collector-emitter conduction responds to incident light in the documented detector arrangement.","On a schematic, identify the collector/emitter connections and any accessible base terminal and trace the optical sensing and load circuit. Keep the component tag and signal/reference names consistent across the control drawing, terminal schedule and device documentation.","A phototransistor provides transistor action; a photodiode generates a different detector current response.","Terminal letters describe electrical roles, not package pin numbers. Check the selected public datasheet for the actual pin assignment, polarity and any internally connected terminals before completing the drawing."],"readingNotes":["Identify the collector/emitter connections and any accessible base terminal.","Trace the optical sensing and load circuit."],"drawingChecklist":["Label the collector/emitter connections and any accessible base terminal.","Cross-reference the optical sensing and load circuit.","Add the selected device or circuit documentation revision, power/reference connections and project signal convention."],"distinction":"A phototransistor provides transistor action; a photodiode generates a different detector current response.","facts":[{"label":"Common schematic mnemonic","value":"PHOTO-NPN — descriptive only; project/device documentation defines reference designations."},{"label":"Terminal / interface focus","value":"The collector/emitter connections and any accessible base terminal"},{"label":"Artwork scope","value":"Original educational component glyph; not a certified standard graphic or package pinout."}],"references":[{"sourceId":"pub-electronics-vishay-optical","relevance":"Public primary manufacturer documentation establishes the component function or circuit/topology relationship. Preview geometry and drafting explanations are independently authored."}],"related":["photodiode","diode"],"artwork":"electronics-photo-npn","publishedOn":"2026-10-14","updatedOn":"2026-10-14","provenance":"independent-public-research","url":"https://eloragrid.ai/symbols/npn-phototransistor","illustration":{"url":"https://eloragrid.ai/library/illustrations/npn-phototransistor.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"pub-electronics-vishay-optical","title":"BPW77 silicon NPN phototransistor documentation","publisher":"Vishay","url":"https://www.vishay.com/docs/81527/bpw77n.pdf","type":"manufacturer","scope":"Public detector documentation identifying NPN transistor action and terminal roles. Optical package geometry and measurement curves remain on the publisher site.","checkedOn":"2026-10-14","reuse":"link-only","relevance":"Public primary manufacturer documentation establishes the component function or circuit/topology relationship. Preview geometry and drafting explanations are independently authored."}]}