jumbo & segment 4 " display drive

Discussion in 'General Electronics Chat' started by sathiyakumar, Mar 15, 2014.

  1. sathiyakumar

    Thread Starter New Member

    Mar 28, 2012
    3
    0
    i tried to lid up 8 (Digit) common anode seven segment jumbo display (4" size)using pic 16f877a micro controller in master and slave mode.

    i used uln2003 for drive the segments and tip127 for source drive from controller.

    every things ok when i lid 4 digits. but for all the 8 digits, the brightness reduced to half as before.

    i am using PC SMPS 12v 5a rating.

    please guide me solve the problem
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,348
    Hello,

    Can you post a schematic and the code of the PIC?
    Also a datasheet of the used displays will give more info.

    Bertus
     
  3. JohnInTX

    Moderator

    Jun 26, 2012
    2,348
    1,029
    If you are multiplexing the digits, you will need to double the current into the segments when going from 4 to 8 digits to get the same perceived brightness.
     
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