Domain: Engineering — Electrical Engineering
Target concept: NOT gate constructed using a single transistor, used to invert the state of an LED

Video generation prompt: A simple NOT gate circuit on a breadboard using an NPN transistor, battery, resistor, and LED; a hand is toggling the switch to provide input to the base of the transistor.

Evaluation guide:
(i) Target concept: Binary logic inversion via transistor saturation/cutoff.
Minimum mechanism: NPN transistor must be forward-biased at base-emitter junction when switch closes, causing collector-emitter path to conduct and shunt LED current away (or vice versa, depending on common-emitter vs common-collector topology, but observable inversion must hold); LED must be current-limited by resistor; no external controller or IC involved.
(ii)Storyline: [Frame 0–2] Static wide shot: breadboard with all components pre-placed, switch in OPEN position, LED ON. [Frame 3–5] Hand enters frame, approaches and contacts toggle switch. [Frame 6–7] Switch lever moves decisively from OPEN to CLOSED position. [Frame 8] LED extinguishes synchronously with lever reaching CLOSED position. [Frame 9–10] Stable final state: switch CLOSED, LED OFF. All events occur in fixed frontal view with no cuts, no occlusion of LED/transistor/switch junctions, and consistent lighting.

Manual:
Experimental Procedure
1. Place NPN transistor, LED, resistor, battery, and toggle switch on breadboard.
2. Connect battery (+) to resistor; resistor to transistor base; transistor emitter to battery (−); transistor collector to LED anode; LED cathode to battery (−).
3. Hand toggles switch to connect/disconnect base resistor to battery (+).
Observation of Experimental Phenomena
When switch is OPEN → LED is ON; when switch is CLOSED → LED is OFF (or vice versa, depending on circuit polarity — but state inversion is visually unambiguous).
Summary of Experimental Principles
A single NPN transistor acts as a voltage-controlled switch: base current controls collector-emitter conduction. With proper biasing, it implements logical NOT — output (LED state) is inverted relative to input (switch state).

Prompt Grounding rubric:
level_1: No breadboard present; no NPN transistor visible; no LED present; no battery visible; no resistor visible; no toggle switch visible; no hand present; no circuit assembly shown.
level_2: Breadboard and at least two of: NPN transistor, LED, battery, resistor, toggle switch present; but components are not assembled into a recognizable circuit layout; hand is absent or performing unrelated action; no toggling motion shown.
level_3: All five core objects present: breadboard, NPN transistor, LED, battery, resistor, and toggle switch; hand is present and visibly contacting the toggle switch; components are placed on breadboard in approximate proximity consistent with a NOT gate layout; no visible wiring errors that break object identity (e.g., LED not mounted, transistor missing legs); sequence shows hand approaching switch but no toggle motion completed.
level_4: All five core objects present and correctly identifiable by form and placement; hand is visibly contacting the toggle switch and executing a clear, unambiguous toggle motion (i.e., switch lever moves between two distinct stable positions); LED and transistor are mounted on same breadboard; battery and resistor are connected in same scene; no object is occluded, duplicated, or misidentified; all objects remain continuously visible throughout the 10-second clip.
level_5: All conditions for score 4 satisfied AND: toggle motion occurs exactly once during the clip; LED changes state (on↔off) precisely once, synchronized with the toggle motion; no extraneous objects (e.g., tools, labels, fingers not part of hand), no transient artifacts (e.g., flicker, reflection, blur obscuring component identity), no viewpoint shift or zoom; fixed frontal view showing full breadboard with all components fully in-frame and undistorted.

Scientific and Causal Correctness rubric:
level_1: The LED's brightness never changes across the whole clip no matter what the switch does, or the LED turns on right as the switch closes and off right as it opens (the reverse of what this cutoff/saturation circuit drives), or the part standing in for the transistor is clearly some other device (e.g., a diode, an IC, or a part with only two leads instead of three).
level_2: The LED does change brightness, but the change happens well before the switch lever finishes its motion or well after it has already settled, so the change isn't tied to the toggle; or the LED is shown carrying current without the collector-branch resistor visibly seated along its path (the component that actually limits LED current).
level_3: The LED changes brightness exactly once, going from lit to unlit (or unlit to lit) in the same frame range where the switch lever finishes crossing to its new position, with the LED lit precisely when the switch sits in the position that leaves the transistor cut off, and unlit when the switch sits in the position that drives the transistor into saturation; the base resistor and the collector-branch resistor both remain visibly seated in their positions.
level_4: Everything in the 3-point description holds, and in addition the LED's ON state is one steady brightness with no flicker, pulsing, or partial glow, its OFF state shows no visible glow at all, the transistor's body shows no scorching, melting, or discoloration, and only one full switch-then-LED-response cycle occurs in the clip.
level_5: Everything in the 4-point description holds, and in addition the LED's brightness change follows the switch lever settling into its new position with no noticeable delay to the eye, the LED's lit color stays one consistent hue with no drifting or fading, and if the switch is toggled a second time, the LED responds with the same direction and immediacy as the first toggle.

Spatiotemporal Consistency rubric:
level_1: Objects teleport (e.g., switch appears/disappears mid-clip); LED jumps position; breadboard rotates or scales abruptly; hand vanishes then reappears; lighting changes discontinuously (e.g., bright → dark in one frame); shadow direction flips without cause.
level_2: One or more objects exhibit severe motion blur preventing identification; breadboard shifts laterally or vertically by >1/4 of its visible width; hand enters frame already in contact with switch (no approach phase); LED changes state before switch motion begins or >1 second after motion ends; lighting flickers or strobes.
level_3: All objects maintain fixed spatial relationships: breadboard remains centered and unmoving; transistor, LED, resistor, battery, and switch retain relative adjacency as seen in standard breadboard NOT gate layout; hand approaches, contacts, and toggles switch in continuous motion without freeze or jump; LED state change occurs within the same continuous shot with no cut; shadows and highlights remain directionally consistent.
level_4: All conditions for score 3 satisfied AND: no inter-frame jitter or micro-shakes affecting object edges; no warping or perspective distortion of breadboard grid or component leads; no occlusion of critical junctions (e.g., transistor base lead hidden during toggle); no abrupt brightness change across frames; motion of switch lever is smooth and monotonic (no reversal, hesitation, or overshoot).
level_5: All conditions for score 4 satisfied AND: zero geometric distortion (breadboard rows/columns remain perfectly parallel and evenly spaced); zero temporal aliasing (switch lever motion shows no strobing or skipping); zero parallax shift (all objects stay locked in same relative plane, with no depth layering inconsistency); zero lighting discontinuity (specular highlights move naturally with hand motion; ambient illumination constant).