{"slug": "i-asked-deepseek-to-design-a-band-pass-filter-what-i-learned-wasn-t-about-the", "title": "I asked DeepSeek to design a band-pass filter. What I learned wasn't about the filter.", "summary": "A developer prompted DeepSeek to design a band-pass filter with a 1 kHz lower cutoff, 10 kHz upper cutoff, and a gain of 50 using a 741 op-amp. The model produced a clean two-stage design and flagged the 741's 1 MHz gain-bandwidth product as leaving almost no margin at that gain, recommending better op-amps and an alternative topology. The developer notes the model could write a Python script to sweep frequency and input voltage but could not execute it, concluding that AI writes the test while the human still runs it.", "body_md": "My prompt: \"Design a band-pass filter with lower cutoff at 1 kHz and upper cutoff at 10 kHz. Use a 741 and set the gain to 50.\"\n\nIt gave a clean two-stage design. It also flagged the 741's 1 MHz gain-bandwidth product, which leaves almost no margin at a gain of 50, and recommended better op-amps and an alternative topology.\n\nSo DeepSeek gave me a textbook solution—and named the 741's limits itself. What it couldn't know is what I never told it: my supply rails and my maximum input amplitude.\n\nThat raised the real question. What solution was I expecting? In a classroom, the textbook answer is appropriate. In the lab, building a prototype, will it meet spec? Probably—maybe.\n\nBetter still: why not ask DeepSeek to test it? Sweep the frequency from 0.1 kHz to 100 kHz, vary the input from 0.1 V to 5.0 V, and plot the output.\n\nBut can DeepSeek run that test? It can write the Python script. It cannot execute it.\n\nSo the boundary is clear. **AI writes the test. I run the test.** There are tools emerging that close this gap—MCP servers that let a model drive ngspice or LTspice directly—but for now, the experimenter is still me.\n\nWhich means the next step is mine: run the sweep, and see whether the prototype matches the simulation.", "url": "https://wpnews.pro/news/i-asked-deepseek-to-design-a-band-pass-filter-what-i-learned-wasn-t-about-the", "canonical_source": "https://dev.to/rslruiz/i-asked-deepseek-to-design-a-band-pass-filter-what-i-learned-wasnt-about-the-filter-2gn6", "published_at": "2026-09-15 14:35:31+00:00", "updated_at": "2026-09-15 14:52:38.283485+00:00", "lang": "en", "topics": ["ai-tools", "large-language-models", "artificial-intelligence"], "entities": ["DeepSeek", "741", "ngspice", "LTspice", "Python"], "alternates": {"html": "https://wpnews.pro/news/i-asked-deepseek-to-design-a-band-pass-filter-what-i-learned-wasn-t-about-the", "markdown": "https://wpnews.pro/news/i-asked-deepseek-to-design-a-band-pass-filter-what-i-learned-wasn-t-about-the.md", "text": "https://wpnews.pro/news/i-asked-deepseek-to-design-a-band-pass-filter-what-i-learned-wasn-t-about-the.txt", "jsonld": "https://wpnews.pro/news/i-asked-deepseek-to-design-a-band-pass-filter-what-i-learned-wasn-t-about-the.jsonld"}}