Simulation

Passives are netlisted automatically and power rails are discovered from the Power objects already attached to the circuit — pass Power arguments explicitly to force the sources. Returns a SimulationContext for running an analysis. Needs the ngspice binary in your PATH — one of the optional installs listed in Getting started.

Example first

import { PCB, Resistor, Power } from '@typecad/pcb';

let typecad = new PCB('typecad');

let r1 = new Resistor({ value: '10k', size: '0603' });
let r2 = new Resistor({ value: '10k', size: '0603' });
let vin = new Power({ power: r1.pin(1), gnd: r2.pin(2), voltage: 5 });

typecad.named('in').net(r1.pin(1));
typecad.named('vdiv').net(r1.pin(2), r2.pin(1));
typecad.named('gnd').net(r2.pin(2));
typecad.add(r1, r2);

const result = typecad.simulate().op();
if (result) {
  console.log(result.getVoltage('vdiv'));         // 2.5 — the divider midpoint
  console.log(result.getCurrent(r1.reference));   // 0.00025 A
  console.log(result.getPower(r1.reference));     // 0.000625 W
}

Four analyses, all headless — results come back as a parsed NgspiceResult, not plot windows. Each writes the netlist to ./build/ first, so what ngspice ran is always inspectable.

const result = typecad.simulate().tran('1u', '10m');
// headless: returns the parsed waveform — no plot windows, no blocking
const v = result?.getWaveform('v(vdiv)');

typecad.simulate().tran('1u', '10m', 0, undefined, false, true);  // openPlots = true

const led = new Power({ power: r1.pin(1), gnd: r2.pin(2), voltage: 5, name: 'VS' });

for (const r of typecad.simulate().dc('VS', 0, 5, 0.25)?.getWaveform('v(vdiv)') ?? []) {
  console.log(r);
}

const ac = typecad.simulate().ac('dec', 20, 10, 1e6);
ac?.getDb('v(vout)');      // Bode-style magnitude
ac?.getPhaseDeg('v(vout)');

typecad-pcb simulate solves the operating point for the board viewer: it re-runs the project entry exactly like a build, writes build/<board>_op.json beside the netlist, and the viewer's ngspice view picks it up on the next refresh — trace hover then shows each net's voltage and the connected devices' current and power. Operating-point only; for other analyses use the API.

Example first

typecad-pcb simulate   # re-runs the entry, solves the OP, writes build/<board>_op.json
# the board viewer's ngspice view reads it — hover a trace for volts / amps / watts

Simulation runs in your build code, so the checks travel with the design. Assert the divider really divides, the LED current really limits — and fail the build when physics disagrees with intent.

Example first

const vdiv = typecad.simulate().op()?.getVoltage('vdiv');
if (vdiv !== undefined && Math.abs(vdiv - 2.5) > 0.01) {
  typecad.error(`divider midpoint is ${vdiv} V, expected 2.5 V`);
}