Voice Sentinel

Duration: 0:14:00

Year Published: 1950

Format: 16mm

Color: B&W

Sound: sound

Description: Uses animation and working models to demonstrate the piezoelectric quality of quartz crystals. Shows how this quality has been applied to the frequency control of many channels in a single conductor. Emphasizes that the quartz crystal serves as the controlling heart of the vast network of telephone and radio. Goes behind the scenes to show how Western Electric's plants cut and grind quartz to exacting tolerances for the Bell Telephone System.

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