How to display values on 3 7 segment displays

Discussion in 'The Projects Forum' started by MC352, May 10, 2011.

  1. MC352

    Thread Starter New Member

    Apr 28, 2011
    5
    0
    I want to be able to display -

    OFF, A and B in 3 seven segment displays when I change the position of a center off switch, from on to off, to on. I was thinking about 3 seven segment displays mounted in a row,

    Left display one would display the A, and the O in off.
    Center display would display the F in off
    The third display would display B, and the last F in the word OFF.

    Is there a fairly simple circuit I can use to do this?

    Thanks in advance for your help.
     
  2. Pencil

    Active Member

    Dec 8, 2009
    271
    38
    ***EDIT**

    Incorrect schematic removed.
    See post #5 for corrected schematic.

    ***EDIT**
     
    Last edited: May 11, 2011
  3. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
    You can hard wire the segments with appropriate resistors. The "A" will take 6; the "B" will take 7 and look like an 8 to most people unless you make it lower case saving 2 resistors; and the word "OFF" will take another 14. Add 3 more if you want to light up the decimal point on unused segments just for fun and a total of 30 resistors all the same. If you want to make it look a little neater, use resistor packs, SIP or DIP.
     
  4. MC352

    Thread Starter New Member

    Apr 28, 2011
    5
    0
    This gets me started, thanks folks!
     
  5. Pencil

    Active Member

    Dec 8, 2009
    271
    38
    Here's the corrected version.

    Three position switch. (OFF, A out, B out).

    Note: 7-segment is common cathode type.
     
  6. nbw

    Member

    May 8, 2011
    36
    10
    I concur - hardwired seems to be the easiest way, with identical and individual resistors for each segment. If you are doing a microcontroller app and were controlling the segments that way, you might also be able to get other letters / combinations.
     
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