PCB...4 Layer...Capacitor

Discussion in 'The Projects Forum' started by dledge, Dec 5, 2014.

  1. dledge

    Thread Starter Member

    Feb 11, 2014
    I'm creating my first PCB layout. I am going with a 4 layer board, where two of the interior layers are Power and Ground. The circuit contains a H-Bridge created with two relays that drive a motor. I wanted to put a capacitor near these relays to ensure they have a solid voltage during start up and switching.

    I am unclear on how to isolate the capacitor so that it is 'seen' primarily by the relays.

    Please see the attached diagram. The H-Bridge is located on the right side and the capacitor in question is C3. Currently, I have the capacitor tied to the ground layer, but the positive pole is traced to the relays' power nodes. These nodes are tied to the power layer.

    I'm using this same approach when placing the caps across the IC Logic chips.

    Any feedback on this approach would be greatly appreciated.