{"slug": "circuitjs", "name": "CircuitJS", "category": "other", "category_name": "Other software", "description": "", "recommenders": 3, "commenters": 3, "warners": 0, "score": 2.86, "rising": 2.67, "first": "2026-02-24", "latest": "2026-08-17", "why": "Circuitjs  https://www.falstad.com/circuit/circuitjs.html allows you to edit components live unlike spice simulators", "why_is_quote": true, "has_verdict": false, "sentiment": {"recommend": 4, "neutral": 0, "compare": 0, "warn": 0}, "spark": [0, 0, 0, 1, 0, 0, 0, 0, 0, 3, 0, 0], "listed": true, "loved": [], "caveat": "", "short_quote": "Circuitjs  https://www.falstad.com/circuit/circuitjs.html allows you to edit components live unlike spice simulators", "icon": true, "domain": "falstad.com", "github_repo": null, "official_url": "https://www.falstad.com/circuit/", "pricing": "", "aliases": ["CircuitJS"], "verdict": null, "praise": [{"label": "", "summary": "", "quotes": [{"id": 789357616, "item_id": 49334851, "url": "https://news.ycombinator.com/item?id=49334851", "by": "eternityforest", "date": "2026-08-17", "stance": "recommend", "quote": "I use it rather often in professional projects", "excerpt": "I use it rather often in professional projects, usually for figuring out power supply inrush transients, and I usually point anyone who wants to learn electronics to it. Just be sure you set the simulation step size appropriately if there's high frequency stuff happening, or the results will not make any sense.", "context": "professional electronics projects", "use_case": "power supply inrush transient simulation", "switched_from": "", "story": "Falstad Math and Physics Simulations"}, {"id": 789269088, "item_id": 49329318, "url": "https://news.ycombinator.com/item?id=49329318", "by": "Surac", "date": "2026-08-17", "stance": "recommend", "quote": "I use there circuit.js for teaching. A realy usefull tool", "excerpt": "I use there circuit.js for teaching. A realy usefull tool", "context": "teacher", "use_case": "teaching electronics", "switched_from": "", "story": "Falstad Math and Physics Simulations"}, {"id": 789097680, "item_id": 49318605, "url": "https://news.ycombinator.com/item?id=49318605", "by": "peterus", "date": "2026-08-16", "stance": "recommend", "quote": "a very useful circuit simulator which I regularly use for prototyping", "excerpt": "He also made circuitjs, a very useful circuit simulator which I regularly use for prototyping. It lets you modify and probe elements in real time unlike spice simulators, so it is faster to modify a design in it. 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Circuitjs https://www.falstad.com/circuit/circuitjs.html allows you to edit components live unlike spice simulators, but with the tradeoff of convergence issues for more complex circuits, so I use circuitjs as a playground then use LTspice as a rigorous simulator. 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I use spice simulators to check the final design since sometimes circuitjs can have instability issues in complex circuits involving stuff like the nonideal op amp. https://www.falstad.com/circuit/circuitjs.", "context": "", "use_case": "circuit prototyping", "switched_from": "", "story": "Falstad Math and Physics Simulations"}, {"id": 754231200, "item_id": 47139450, "url": "https://news.ycombinator.com/item?id=47139450", "by": "peterus", "date": "2026-02-24", "stance": "recommend", "quote": "Circuitjs  https://www.falstad.com/circuit/circuitjs.html allows you to edit components live unlike spice simulators", "excerpt": "I've found a combination of circuitjs and a spice simulator to be quick for prototyping custom analog circuits (made mainly from discretes). Circuitjs https://www.falstad.com/circuit/circuitjs.html allows you to edit components live unlike spice simulators, but with the tradeoff of convergence issues for more complex circuits, so I use circuitjs as a playground then use LTspice as a rigorous simulator. If it's a circ", "context": "", "use_case": "prototyping analog circuits", "switched_from": "", "story": "Diode \u2013 Build, program, and simulate hardware"}]}