Gallery, prompt v1

Triangle-wave carrier for a milk frother

One frozen prompt and every model that has run it, newest first.

Saturated since 2026-10-02

It is off the board. DeepSeek 4.1 Flash passed every check in all three runs on 2026-09-22, and GPT-6.1 Sol did the same on 2026-10-02, each on its first render. Both built the comparator from an ideal behavioural source, which the prompt allows, so the harder version takes that away.

The prompt, v1, frozen

A milk frother's heater is driven by PWM, and the PWM needs a 1 kHz triangle-wave carrier of 2 V peak to peak. Build that oscillator in ngspice using only DC supplies, so the oscillation comes from the circuit itself, and simulate 20 ms. In a .control block, save the carrier voltage with wrdata to a .txt file so it can be plotted.

Every model, its first three runs.

One square a check, in this order:

  1. DC supplies only
  2. 1 kHz
  3. 2 V peak to peak
  4. Straight, even ramps

passed, failed, undecided. A round mark is a check I judged by eye, and a diamond one a check a model judged.

GPT-6.1 Sol
DeepSeek 4.1 Flash

How it is checked

The netlist, re-run in ngspice offline and the written carrier read back. A triangle comes from integrating a square wave, so a PULSE into an RC, whose ramps curve, fails, and so does any source that is told the time.

DC supplies onlymeasuredNo PULSE, SIN or PWL source, and no behavioural source that reads time.
1 kHzmeasuredIt runs, oscillates, and settles within 10% of 1 kHz.
2 V peak to peakmeasuredWithin 10% of 2 V once settled.
Straight, even rampsmeasuredEach ramp fitted to a line with little bend, and rise and fall about equal.

What replaces it: Require a real op-amp model with finite slew and supply rails, so an ideal behavioural comparator is not allowed.

The rules behind all of thisThis task's prompt, checks and any checker, on GitHub