when was the first digital alarm clock invented
Digital clock The earliest patent for a digital alarm clock was registered by D.E Protzmann and others on October 23, 1956, in the United States. Protzmann and his associates also patented another digital clock in 1970, which was said to use a minimal amount of moving parts. Two side-plates held digital numerals between them, while an electric motor and cam gear outside controlled movement.[2]