CopperPilot can run a full engineering loop inside LTspice, not just answer circuit
questions. In this workflow, it designs a Sallen-Key low-pass filter, runs simulation,
iterates values to meet updated specs, and validates stability with technical evidence.
Overview
Starting from a concrete task, CopperPilot generates the LTspice netlist, runs batch AC
analysis, parses the raw results, and reports Bode magnitude and phase behavior. The first
pass lands near 482 Hz, consistent with the initial RC choices.
Engineering Loop
When requirements change to target 500 Hz with minimal edits, CopperPilot keeps capacitor
values fixed at 10 nF, recalculates resistor values to 31.83 kOhm, updates the netlist, and
reruns simulation. The rerun confirms the natural frequency is approximately 500 Hz, closing
the loop with measured results instead of static recommendations.
Stability Analysis
CopperPilot extends beyond tuning by generating pole-zero analysis and interpreting phase
margin and stability in context. It explains the pole location in the left half-plane and
provides stability reasoning tied to the Sallen-Key topology and op-amp behavior.
Key Takeaways
- Requirement to simulation loop is automated: netlist generation, batch run, parsing, and reporting.
- Specification updates are implemented directly in the netlist and revalidated through rerun data.
- Stability interpretation includes pole-zero evidence and phase-margin reasoning, not just pass/fail output.