70 lines
2.2 KiB
TypeScript
70 lines
2.2 KiB
TypeScript
import { describe, it, expect } from 'vitest';
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import { runNetlist, NL } from './helpers/testSolver';
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describe('ngspice — transient analysis', () => {
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it(
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'RC charging: V(τ) ≈ 63.2% of Vsource (R=10k, C=100µF, V=5V)',
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{ timeout: 30_000 },
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async () => {
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const netlist = `RC charging
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${NL.pulse('V1', 'vcc', '0', 0, 5, 0, '1n', '1n', 10, 20)}
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R1 vcc out 10k
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C1 out 0 100u IC=0
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.tran 10m 3
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.ic v(out)=0
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.end`;
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const { vec } = await runNetlist(netlist);
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const t = vec('time') as number[];
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const v = vec('v(out)') as number[];
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const tau = 10_000 * 100e-6; // 1 s
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let bestI = 0;
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let bestDt = Infinity;
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for (let i = 0; i < t.length; i++) {
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const d = Math.abs(t[i] - tau);
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if (d < bestDt) {
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bestDt = d;
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bestI = i;
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}
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}
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const vAtTau = v[bestI];
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const expected = 5 * (1 - 1 / Math.E);
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expect(vAtTau).toBeGreaterThan(expected * 0.97);
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expect(vAtTau).toBeLessThan(expected * 1.03);
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},
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);
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it(
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'RLC oscillator: underdamped ringing with expected frequency',
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{ timeout: 30_000 },
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async () => {
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// L=10mH, C=10µF → f0 ≈ 503 Hz. Light damping via R=1Ω.
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const netlist = `RLC ringing
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V1 in 0 PULSE(0 5 1m 1u 1u 1 2)
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R1 in n1 1
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L1 n1 out 10m
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C1 out 0 10u IC=0
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.tran 10u 30m
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.end`;
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const { vec } = await runNetlist(netlist);
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const t = vec('time') as number[];
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const v = vec('v(out)') as number[];
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const crossings: number[] = [];
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for (let i = 1; i < t.length; i++) {
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if (t[i] < 2e-3) continue;
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const a = v[i - 1] - 2.5;
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const b = v[i] - 2.5;
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if (a * b < 0) crossings.push(t[i]);
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}
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expect(crossings.length).toBeGreaterThan(4);
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const diffs: number[] = [];
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for (let i = 1; i < crossings.length; i++) diffs.push(crossings[i] - crossings[i - 1]);
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const avgHalf = diffs.reduce((s, d) => s + d, 0) / diffs.length;
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const measuredF = 1 / (2 * avgHalf);
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const expectedF = 1 / (2 * Math.PI * Math.sqrt(10e-3 * 10e-6));
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expect(measuredF).toBeGreaterThan(expectedF * 0.85);
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expect(measuredF).toBeLessThan(expectedF * 1.15);
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},
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);
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});
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