When Did Digital Clocks Start?

Digital clocks display the time with characters. This is in contrast to analog clocks that use other methods such as hands to show the time. Digital clocks date from the early 20th century and have undergone some advancements since then.

Origins

A plato clock is the earliest example of a digital clock. It consists of a spring-wound mechanism that flips over a series of cards with the passage of time. The cards have numbers printed on them, which show the time. Plato clocks were first demonstrated in 1904 at the St. Louis World Fair.

Mechanical Design

The first digital timepiece that was based on a purely mechanical design was invented in 1956 by Josef Pallweber and included an alarm function. D. E. Protzmann patented a design for a digital clock that used a minimum of moving parts in 1970. This design used a cam gear driven by an electric motor to control the movements of the clock.

LED Display

Digital watches require more light to read than an analog display and typically use a light-emitting diode as a light source. The first commercial production of digital watches with an LED display began in 1970. The LED initially made the watches expensive, but the priced dropped steadily with advances in their manufacture.

Modern Design

Digital watches began to cost less than analog watches in 1975. These watches rely on the oscillation frequency of a quartz crystal to keep time. This design makes digital watches accurate to within a half-second per day.