light valve

noun

Electricity.

1. a light-transmitting device having transmissions that vary in accordance with an electric input, as voltage, current, or an electron beam, used chiefly for recording sound on motion-picture film.

Word History and Origins

Origin of light valve¹

First recorded in 1925–30

Example Sentences

He and two other engineers invented a computerized light valve monitoring system allowing all prints to maintain the picture quality of the original film.

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It is possible to extend the limits considerably by using a light valve on a strong spring, but the valve still remains a limiting factor in the speed of the motor.

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The mouth is placed against the aperture o, which fits closely round the lips, and the filtered air enters the mouth through a light valve v, which is lifted by the act of inhalation.

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