Editing Binary clock (section)

== Binary-coded decimal clocks ==
[[File:Binary clock.svg|thumbnail|right|Reading a [[binary-coded decimal]] clock: Add the values of each column of [[Light-emitting diode|LEDs]] to get six decimal digits. There are two columns each for hours, minutes and seconds.]]
[[File:Digital-BCD-clock.jpg|thumbnail|right|Both clocks read 12:15:45.]]

Most common binary clocks  use six columns of [[LED]]s to represent [[0 (number)|zeros]] and [[1 (number)|ones]]. Each column represents a single decimal digit, a format known as [[binary-coded decimal]] (BCD). The bottom row in each column represents 1 (or 2<sup>0</sup>), with each row above representing higher powers of two, up to 2<sup>3</sup> (or 8). 

To read each individual digit in the time, the user adds the values that each illuminated [[light-emitting diode|LED]] represents, then reads these from left to right. The first two columns represent the [[hour]], the next two represent the [[minute]] and the last two represent the [[second]]. Since zero digits are not illuminated, the positions of each digit must be memorized if the clock is to be usable in the dark.