The matrix has seven columns, one for each segment on the display ... [Fran]’s circuit using a 555 and a 4017B decade counter to make a display count down to 0.

At its heart the device simply counts the oscillations of an input signal for one second, then latches the total to the 7-segment displays before zeroing the counter block and starting over.

7-segment displays are used to display numerical information and consist of seven LEDs to form numbers 0-9, often controlled by a decade counter IC for accurate counting and display. Back to top ...