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 interesting puzzle.
If you get stuck, check the hints below.
The overall shape of the circuit is a hint.
Have a look at the outputs, why they have letters and not numbers?
A real circuit like this would have four inputs, not only three. It makes it so much more useful.
The outputs are connected to seven LEDs which are arranged in a special way.
This circuit is a 7-segment display driver with only 3-bit input. It displays the digits
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
G to each segment.
Real-World Design with Matrix
To build a complete 7-segment driver, you start with a binary decoder. The decoder will convert the binary encoded numbers from
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.
- The circuit displays the digit
7in an alternate form, adding the segment
F. Do you find out, why this decision was made?
- Design a circuit that displays a signed 4-bit number, including the existing digital circuit. The minus sign will be an additional output Iminus.
I hope you enjoyed this logic circuit puzzle. Let me know if you like to see more puzzle like this.
If you have any questions, missed information, or simply want to provide feedback, feel free to comment below. 😄