published: May 1, 2021 — last modified: October 23, 2025
The shown logic circuit performs a handy function; can you discover what it is?
The circuit was not optimised for functionality but to create a nice artwork and exciting puzzle.
If you need to know the meaning of logic gate symbols, look at this Wikipedia page. Also, there are great videos from Ben Eater on how to build real digital logic circuits.
If you get stuck, check the hints below.
This circuit is a 7-segment display driver with only 3-bit input. It displays the digits 0 to 7 on an attached 7-segment display.
You find more details about 7-segment displays on this Wikipedia page. Here you also find the common assignments of the letters A to G to each segment.
To build a complete 7-segment driver, you start with a binary decoder. The decoder will convert the binary encoded numbers from 0000 to 1111 into 16 distinctive signals.
Then you create a matrix from these 16 signals and the seven outputs. If a segment should light up for one of the 16 distinctive signals, you connect it using a diode.
For a wonderful example, see Fran’s great video about diode steering.
7 in an alternate form, adding the segment in an alternate form, adding the segment F. Do you find out, . Do you find out, why this decision was made? this decision was made?I hope you enjoyed this logic circuit puzzle. Let me know if you like to see more puzzles like this.
If you have any questions, missed information, or want to provide feedback, feel free to comment below. 😄
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