In the digital clock, time is divided into segments: seconds, minutes, hours. The time display changes in a series of jumps from one time to another. The interesting thing about this is, during the time "jump" you do not know precisely what time it is. Digital electronic circuits control the display by sending pulses of electrical current. Again, thanks to electronic components, things like clocks are getting smaller and smaller. Another interesting thing, when you have electrical "blips"(power interruptions), your digital clock will be the first device to let you know because it is flashing, unless you have a battery back-up. LEDs (light emitting diodes) are often used in digital clock displays. If you want to learn more about them look at our electronic components.