LED Driver question/suggestions

Discussion in 'The Projects Forum' started by Jassper, Sep 13, 2009.

  1. Jassper

    Thread Starter Active Member

    Sep 24, 2008
    I have the circuit below useing the http://www.national.com/mpf/LM/LM3914.html LM3914 LED Dot/Bar driver and a 10 segment LED. It is basically constructed as the typical 0-5v bar graph meter, Tested and everything works out pretty good. The bar climbs in 10% increments so the display is from 10% to 100%.

    The 12v regulator really isn't needed, but I included it to help stableize the main power.

    One question I have is if I should also include a capacitor on each SIG_* input, maybe a 0.33uf to help filter out any transit and noise.

    Also, the data sheet for the LM3914 show a method to make the Bar Flash. I played with this a bit but what I would really like to do is make the pin L1 flash when the SIG_F input is below 10% (< 0.5v) because when the SIG voltage is below 10% no LEDs are lit. I would like some way to indicate this.

    Last edited by a moderator: Sep 13, 2009