7 segment problem proteus

Discussion in 'The Projects Forum' started by MrYu, Jul 11, 2012.

  1. MrYu

    Thread Starter Member

    Sep 26, 2011
    42
    0
    how to fix 7 segment in isis , it won't appear it's value in ARES even i fix the packaging and set the footprint in ISIS
     
  2. PaulEE

    Member

    Dec 23, 2011
    423
    32
    Model it as separate LEDs instead of a display? Not sure what you're trying to accomplish...
     
  3. absf

    Senior Member

    Dec 29, 2010
    1,492
    372
    I created a simple 2 chips design and I have no problem with the PCB.

    Did you uncheck the box "Exclude from PCB Layout"?


    Allen
     
    MrYu likes this.
  4. MrYu

    Thread Starter Member

    Sep 26, 2011
    42
    0
    yeah it works fine now i uncheck the exclude from PCB layout
     
  5. MrYu

    Thread Starter Member

    Sep 26, 2011
    42
    0
    i have another problem in actual building of this circuit when i test the pin QA to QG of 7448 IC in multimeter,. i only get 1.5v and sometimes just 1v. i bought it a while ago. is it possible that the IC is broken?

    http://imageshack.us/photo/my-images/705/95525217.jpg/
     
  6. MrYu

    Thread Starter Member

    Sep 26, 2011
    42
    0
  7. absf

    Senior Member

    Dec 29, 2010
    1,492
    372
    From my datasheet the 74148 can only source 800uA and sink 16mA. The 74LS148 can source 400uA and sink 8mA. (I dont have the datasheet for 7448).

    That's why the voltage dropped so much when you're sourcing them directly from the outputs. Try inverting the outputs using inverters or inverting buffers to the 7 segment CA LED. It should improve the situations of the 7448.

    Allen
     
    MrYu likes this.
  8. MrYu

    Thread Starter Member

    Sep 26, 2011
    42
    0
    yeah i think i found the answer your right.. but what in the world the storekeeper give me
    7447 and i get CC 7 segment. maybe she doesn't know 7447 can't replace 7448 ?
    i'm working this for about 5hrs and tnx i get a lot of knowledge here :D godbless
    http://forum.allaboutcircuits.com/showthread.php?t=36168
     
    Last edited: Jul 13, 2012
Loading...