circuit-simlisted

# sim — simulation dispatcher Route by simulation type. Do NOT run every tool at once — pick the path matching the question. ## 1. SPICE subcircuit (filters, dividers, opamp gain, LC/crystal, ripple) Use the **`spice-sim`** skill — canonical (ngspice/LTspice/Xyce, auto-extracts subcircuits from KiCad). It owns filter cutoff, divider voltage, opamp bandwidth, LC resonance, regulator ripple, transient + AC sweeps. Invoke `spice-sim` rather than hand-rolling ngspice here. ## 2. RF chain / S-parameters (scikit-rf) Cascaded RF blocks (gain, NF, return loss, match): - Confirm lib: `python -c "import skrf"` (`pip install scikit-rf` if missing). - Each stage = `skrf.Network` from Touchstone (`.s2p`) or from R/L/C + `skrf.media`. - Cascade with `**`: `total = amp ** filt ** mixer`; read `total.s_db`, S21 = `total.s[:,1,0]`, `total.z0`. - Friis for chain gain/NF; target input/output match `s11`,`s22` < -10 dB. ## 3. Power / clock transient + AC - Power rail: model LDO/buck output stage in `spice-sim`; step the load, measure droop / ripple / recovery. - Clock: transient on oscillator/buffer net — rise/fall, overshoot, duty; AC on the distribution net for flatness. ## Discipline - One simulator path per question; results are meaningless without the right model/netlist in place first. - State assumptions (models, corners, temperature) with every result. - For KiCad-sourced circuits, let `spice-sim` extract the subcircuit rather than transcribing by hand.