Help needed with Full Adder and seven-segment display circuit

Discussion in 'Homework Help' started by Guest32, Feb 15, 2012.

  1. Guest32

    Thread Starter New Member

    Jan 24, 2012
    5
    0
    Hi again! I'm hoping to get some guidance with my lab assignment. Here are the instructions:
    ___________________________________________________________
    OBJECTIVE:In Multisim, design a circuit that will add two 1-bit numbers using a Full Adder IC. Display the result on a seven-segment display.

    COMPONENTS: Below are the components you will use in your circuit:
    ·Vcc
    ·Rpack – current limiting resistors for MAN72
    ·2-pole dip switch pack (since we are adding only two 1 bit-numbers, A and B)
    ·Full Adder IC
    ·7447 IC (BCD to 7-segment decoder)
    ·7-segment display LED (also known as MAN72, I use common anode type)

    _______________________________________________________________

    I think I have all the components, but I don't know how to hook them up correctly. My simulation did nothing, so I'm way off I guess. I also don't know if the two SPST switches, the 2 grounds, and the 220 resistor are even needed.

    Here's a screen capture of what I have at the moment:
    http://i195.photobucket.com/albums/z53/wmrebel32/lab6start.jpg

    Can someone teach me how to hook this up properly?
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,635
    2,342
    Hello,

    Did you read the datasheet of the 7447?
    sn54ls47.pdf
    At the moment you are setting ALL inputs A-D high or low.
    This will not give the correct output.
    You also try to control the control lines of the 7447 with the carry output of the adder.

    What chip are you using as adder?

    Bertus
     
    Last edited: Feb 15, 2012
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  3. Guest32

    Thread Starter New Member

    Jan 24, 2012
    5
    0
    Hi Bertus,

    I am using the only Full Adder I saw in Multisim - it's called Full_Adder, located in the Misc Digital group, in the TIL family. It has limited info - under Model manufacturer/ID, it says "IIT / FULL_ADDER".


    I'm pretty lost on the full adder and the 7447 seven-segment decoder - I don't understand how to connect and use them. I'm bad at digital electronics in general. I don't have to know it for my job but it's the last class I need for my associates. I appreciate where you told me my mistakes, but I don't understand exactly what you are telling me :(
     
  4. bertus

    Administrator

    Apr 5, 2008
    15,635
    2,342
    Hello,

    When you look at the thruth table, you can see what happens to the displlay:

    [​IMG]

    Bertus
     
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