Digital clock

The first digital pocket watch was the invention of Austrian engineer Josef Pallweber[1] who created his "jump-hour" mechanism in 1883.

The principles of Pallweber jump-hour movement had appeared in wristwatches by the 1920s (Cortébert) and are still used today (Chronoswiss Digiteur).

These spring-wound pieces consisted of a glass cylinder with a column inside, affixed to which were small digital cards with numbers printed on them, which flipped as time passed.

[5] The earliest patent for a digital alarm clock was registered by D. E. Protzmann and others on October 23, 1956, in the United States.

[6] 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.

[3] In 1970, the first digital wristwatch with an LED display was unveiled on The Tonight Show Starring Johnny Carson, although it was not released until 1972.

Because digital clocks can be very small and inexpensive devices that enhance the popularity of product designs, they are often incorporated into all kinds of devices such as cars, radios, televisions, microwave ovens, standard ovens, computers and cell phones.

Basic digital alarm clock without a radio. The mark in the top-left of the display indicates that the time is 4:00pm (16:00), not 4:00am.
A 1969 radio alarm clock (Sony Digimatic 8FC-59W) with an early mechanical-digital display
A digital clock's display changing numbers
This digital clock has been attached to an oven.
This digital clock reacts to temperature.