Extend showcase with advanced circuit demos

[mfiumara]

Summary

Expand the live showcase with visually impressive circuit demonstrations beyond the current RC filter. The goal is demos that make you go "wow, that's nice."

Desired demos

Non-linear circuits

• MOSFET circuits — e.g., CMOS inverter transfer curve (.dc sweep), common-source amplifier transient response
• Diode circuits — half-wave/full-wave rectifier, clipping circuits
• BJT amplifier — common-emitter with biasing, show gain and phase shift

Operational amplifier circuits

• Inverting/non-inverting amplifier — show gain with .step on feedback resistor
• Active filters — Sallen-Key low-pass/band-pass with Bode plots
• Integrator/differentiator — show square wave in, triangle/spike out

Filter impulse responses

• RC/RLC step response — overdamped, critically damped, underdamped ringing
• LC tank circuit — show resonance with decaying oscillation
• Bandpass filter — impulse response showing the ringing envelope
• Notch filter — show the rejection of a specific frequency

Parametric sweeps (.step)

• Sweep component values to show family-of-curves on all the above where it makes sense
• e.g., sweep damping resistor in RLC to show transition from underdamped → overdamped

Notes

• All simulations run client-side in the browser via @spice-ts/core
• Use streaming (simulateStepStream) for progressive rendering where possible
• Current showcase infrastructure supports transient + AC + .step — new demos just need netlists and signal selection
• Some circuits (opamps) may require subcircuit definitions or behavioral models

[mfiumara]

Update — implemented in main (2026-04-14)

All items from this issue have been addressed. Here's what shipped:

New circuits added

Filters

• ✅ RLC Bandpass — transient (impulse response) + AC (Bode plot)
• ✅ Sallen-Key Low-Pass — AC Bode plot (2nd-order, −40 dB/dec, VCVS opamp model)

Non-Linear

• ✅ CMOS Inverter — DC transfer curve (.dc sweep, BSIM3v3 Level 49 NMOS/PMOS)
• ✅ Half-Wave Rectifier — transient, shows both input sine and rectified output
• ✅ Common-Source Amp — AC Bode plot (Level-1 NMOS)

Opamp Circuits

• ✅ Inverting Amplifier — transient + .step param Rf list 1k 10k 100k (family of gain curves)
• ✅ Integrator — transient, square wave in → triangle wave out

Impulse Response

• ✅ RLC Step Response — transient + .step param R1 list 10 200 1k (under/critically/over-damped)
• ✅ LC Tank — transient, decaying oscillation at ~15.9 kHz

Power Electronics (new group, not in original scope)

• ✅ Buck Converter — 12 V → ~6 V, 50% duty, NMOS switch
• ✅ Boost Converter — 5 V → ~10 V, 50% duty
• ✅ Buck-Boost Converter — inverting topology

New infrastructure

• DC sweep panel — new DCSweepPlot component in @spice-ts/ui, uses synchronous simulate() (no streaming needed). Shows transfer curves with cursor + legend.
• Netlist panel — syntax-highlighted netlist view above the waveform, updates with active analysis type. Placeholder for a future schematic renderer.
• Configurable sim params — Stop time and Timestep inputs in the toolbar for transient simulations, pre-filled from the circuit's .tran directive.

Not yet done from this issue

• BJT common-emitter amplifier (.model for BJT not tested yet)
• Full-wave rectifier
• Notch filter
• Differentiator

Live: https://mfiumara.github.io/spice-ts/