Domain: Engineering — Electrical Engineering
Target concept: Relaxation Oscillator Forming a Closed Loop on an XY Monitor (Neon Lamp Circuit)

Video generation prompt: Set up a neon lamp relaxation oscillator, connect the capacitor voltage to the X input of the oscilloscope, and connect the lamp current through a sampling resistor to the Y input. Switch to XY mode and record over time.

Evaluation guide:
(i) Target concept: Voltage-controlled current hysteresis in a gas-discharge relaxation oscillator, visualized as a closed trajectory in XY phase space.
Minimum mechanism: Neon lamp must exhibit bistable conduction (off → on at V_breakdown, on → off at V_extinction) while discharging a capacitor through a series resistor; capacitor must recharge through a separate path (implicit internal resistance or external resistor) to sustain oscillation; oscilloscope XY mode must map instantaneous voltage (X) and proportional current (Y) without timebase.
(ii)Storyline: Frame 1–2: Static shot showing intact circuit, neon lamp adjacent to capacitor, sampling resistor in series with lamp, X-wire from capacitor, Y-wire from resistor, oscilloscope front panel with XY mode visibly selected. Frame 3–5: Lamp off; trace creeps slowly rightward with Y sitting near the baseline (capacitor charging, lamp dark, essentially no current). Frame 6: Lamp flashes brightly; trace jumps sharply upward while sliding left (discharge onset, current surge through the lamp). Frame 7–9: Lamp extinguishes; trace descends back down and left, completing the loop as discharge finishes and current returns to near zero. Frame 10: Loop closes; lamp remains off until next cycle. All events occur from fixed frontal viewpoint; no camera movement; scope screen and lamp remain fully visible and in-focus throughout.

Manual:
Experimental Procedure
1. Connect neon lamp in series with capacitor to form relaxation oscillator loop.
2. Wire capacitor voltage to oscilloscope X-input.
3. Insert sampling resistor in series with neon lamp; wire its voltage to oscilloscope Y-input.
4. Set oscilloscope to XY mode.
Observation of Experimental Phenomena
- Oscilloscope displays a continuous closed-loop trace (hysteresis-style loop).
- Neon lamp flashes briefly once per loop cycle, synchronized to the loop's rightmost, peak-voltage corner.
- Between flashes, lamp is dark; trace creeps slowly rightward at a near-zero Y level (capacitor charging), then jumps sharply upward and to the left as the lamp fires and current surges (discharge), before decaying back down to the starting point.
Summary of Experimental Principles
Neon lamp exhibits negative resistance: it ionizes abruptly at breakdown voltage, discharging the capacitor, then de-ionizes as voltage falls below extinction level — forming a relaxation oscillator. In XY mode, X = capacitor voltage (slow rightward ramp while the lamp is dark), Y = lamp current (stays near zero during charging, spikes upward at discharge), yielding a lopsided hysteresis loop.

Prompt Grounding rubric:
level_1: None of the neon lamp, capacitor, oscilloscope, or sampling resistor is visible; no wire is shown running to the oscilloscope's X or Y input; the oscilloscope is not shown set to XY mode; the circuit is never shown being assembled or connected.
level_2: At least one of the neon lamp, capacitor, oscilloscope, or sampling resistor appears in frame, but none of them are shown correctly wired together; there is no visible X or Y label at the oscilloscope inputs; the XY-mode indicator is missing from the oscilloscope display or front panel; the assembly steps are shown out of order or contradict each other.
level_3: The neon lamp, capacitor, oscilloscope, and sampling resistor are all present; a wire visibly runs from the capacitor terminals to the oscilloscope's X input (labeled X or clearly attached to the X terminal); the sampling resistor sits in series with the neon lamp, and a wire from across that resistor visibly runs to the oscilloscope's Y input; the oscilloscope display or front panel clearly shows XY mode selected.
level_4: Everything at score 3 holds, and additionally the layout is spatially correct: the neon lamp and capacitor form a closed series loop with no dangling or open wire ends; the sampling resistor sits in series with the lamp only (not shorted or wired in parallel); the X-input wire attaches only to the capacitor terminals; the Y-input wire attaches only to the sampling resistor terminals; the oscilloscope screen shows an active, moving trace rather than a blank or frozen display.
level_5: Everything at score 4 holds, and additionally the physical arrangement reads like a real benchtop setup: the neon lamp and capacitor sit side by side on the breadboard, with the sampling resistor immediately next to the lamp; the oscilloscope is angled so both its front-panel controls and its screen are visible at once; the X-input and Y-input wires are distinguishable by color and routed so neither one crosses over or hides the lamp, capacitor, or resistor; the XY-mode selector is shown engaged on the front panel at the same time the screen displays the XY trace.

Scientific and Causal Correctness rubric:
level_1: No repeating flash-and-trace cycle occurs; the oscilloscope screen stays blank, frozen on one still image, or shows only flat, unchanging lines; the neon lamp stays continuously lit or stays completely dark for the whole clip; the lamp never flashes.
level_2: The oscilloscope screen shows some moving trace (e.g., a single sweeping line, random scribble, or plain sine-like wave), but it never closes into a repeating loop shape; the neon lamp glows steadily or blinks at times that don't line up with any turning point of the trace.
level_3: The oscilloscope screen shows a smooth, closed loop trace (not a straight line or open curve) that repeats every cycle; the neon lamp flashes on briefly and periodically, and each flash lines up in time with the corner of the loop farthest to the right, where the capacitor voltage is at its peak; while the trace creeps along the loop's slow, near-flat section between flashes, the lamp stays dark.
level_4: Everything at score 3 holds, and additionally each lamp flash is a brief, instantaneous-looking pulse rather than a sustained glow; the loop traced on screen never crosses over itself and keeps the same winding direction every repeat; most of the loop is visibly curved or angled rather than dominated by one long flat, straight run.
level_5: Everything at score 4 holds, and additionally the instant the lamp flashes at that rightmost, peak-voltage corner, the trace jumps sharply upward (Y rises, reflecting the current surge through the lamp and sampling resistor) before decaying back down as the capacitor finishes discharging; the loop reads as visibly lopsided: a long, nearly flat rightward crawl (slow charging) followed by a short, steep up-then-down excursion (fast discharging).

Spatiotemporal Consistency rubric:
level_1: The neon lamp, capacitor, oscilloscope, or resistor jumps to a new position between frames, or one of them vanishes and then reappears; the wiring between components changes shape or connection point from one frame to the next; the lighting suddenly flips from dark to bright (or the reverse) within a single frame; the breadboard or oscilloscope casing visibly cracks, splits, or changes shape.
level_2: The lamp's flash timing is inconsistent from cycle to cycle for no apparent reason; the trace on the oscilloscope screen jumps to a new position without visibly moving there; the sampling resistor appears rotated or flipped between frames with no cause shown; the shadows cast by the components swing to a noticeably different direction partway through the clip; background items (bench, cables, etc.) shift sideways between frames.
level_3: The neon lamp stays next to the capacitor, the sampling resistor stays in series with the lamp, and the oscilloscope stays put in the frame for the whole clip; the X-input and Y-input wires keep the same routing and the same attachment points throughout; the direction and brightness of the light source stay the same from frame to frame; none of the components stretch, bend, or pass through one another.
level_4: Everything at score 3 holds, and additionally the capacitor-voltage trace on screen advances smoothly with no skipped jumps or points that teleport; the lamp's brightness ramps up and fades out rather than switching instantly between fully off and fully lit; the trace's line thickness stays even and unbroken; component edges and any on-screen labels stay crisp with no tearing or ghosting between frames.
level_5: Everything at score 4 holds, and additionally the lamp's flash and the trace's sharp upward jump happen within the same moment, not offset by a noticeable delay; the trace appears to draw continuously rather than flickering in and out; every wire connecting the components stays taut and unbroken in every frame; the oscilloscope screen's trace stays aligned with the physical screen bezel with no apparent drift between the foreground components and the screen behind them.