Quick LM7815 Grounding Question...

Discussion in 'The Projects Forum' started by jwilli, Aug 3, 2009.

  1. jwilli

    Thread Starter Active Member

    Apr 21, 2009
    Really quick question- I have DC + and - coming onto my board. My board has a 7815 regulator and I was wondering:

    Does it matter how far "down the line" on the board the ground comes to the regulator or is it best to have it connected as close as possible to the incoming ground?

    Thanks in advance!
  2. lightingman

    Senior Member

    Apr 19, 2007

    It should not make much difference, as lone as you have a 100nF and a 10uF capacitor in parallel accross the input and ground pins, as close to the reg as possible. Also the larger the ground tracks are the better.

  3. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    It is always nice to have it connected back close to the incoming ground point. All of the current going through the 7815 will return through that ground connection causing the ground to shift slightly from that of the incoming connection. Depending on the current, distance, how it is connected with relation to other components, it may or may not be a problem for your circuit. A ground plane or a "star ground" may be of interest to you. A star ground is one where local grounds are always brought back to a single point.