| 摘要 |
In a cinematographic projector having an electronic circuit for speed control, a device is provided for interrupting motor supply when standing projection is required. The device comprises an apertured disc rotating with the sector diaphragm of the projector and interposed between a lamp and a photoresistance connected with the electronic speed control circuit for stopping conduction of the circuit when the photoresistance is illuminated. The aperture of the disc is arranged for allowing illumination of the photoresistance when the sector diaphragm leaves a projected photogram entirely free.
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