How do I produce this circuit? (digitally)

Discussion in 'Homework Help' started by poppinfresh12, Nov 16, 2015.

  1. poppinfresh12

    Thread Starter New Member

    Nov 16, 2015
    Hi everyone,

    I am a total novice and I am attempting to teach myself. I'm required to design a circuit to take a binary input and display a number on a 7 segment display. I can only use AND, OR, NOT, NAND and NOR logic gates.

    The numbers need to be displayed sequentially as follows; 1, 5, 6, 6, 9, 5, 5, 7

    I need to use 3 sequencers or bit generators in the circuit as input.

    I have uploaded my truth table. I really do not know if this is correct. At this point I am totally stuck and don't really know what to do. If the truth table is correct then I've managed to also obtain Boolean equations from it. However I still don't know how to build a circuit from this.

    Any help would be hugely appreciated. Thanks for taking the time to read my query.

    p.s. I am being directed to firstly construct a separate circuit for each segment from the truth table you have constructed. Then redraw the circuit to combine the separate circuits to form one complete circuit.

    p.p.s I am eventually required to use a 3-to-8 decoder to simplify/reduce the number of logic gates
  2. absf

    Senior Member

    Dec 29, 2010
    Your truth table would display "AbCdEFgH" and not numbers... Is that what you've wanted?

    Are you going to make the 3-8 decoder using gates too? You can refer to the 74138 datasheet and see how they did it.

    edit: see page 2 of the pdf.

    Last edited: Nov 16, 2015