I am trying my hand in PCB designing recently and I came across an article where it offers tip for PCB designing and everything made some sense to me except the below one? The tip goes this way

When laying out PCB’s, make sure all signal references have an individual trace back to the common node. Do NOT daisy chain common reference points. This will result in hum and noise in analog amplifier circuits.

Well am trying to figure out what exactly this statement come to explain, I have tried forum of that site but no response from them. Can you guys kindly help by explaining the above statement in simplified version so that beginner like me could understand them please?

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    \$\begingroup\$ It means "*", not "TTTT". \$\endgroup\$ – Ignacio Vazquez-Abrams Apr 1 '18 at 17:46
  • \$\begingroup\$ common, is also called ground, signal ground etc, there's a lot of voodoo about grounding, some of it even works. \$\endgroup\$ – Jasen Apr 2 '18 at 0:44

What Ignacio answered is right. I like to add an example for you to understand this rule: Imagine a water tank and two houses with pipes connected to the tank. It is best if both houses have separate pipe connections to the (common) tank, because then they do not disturb each other. If one house has its pipes connected to the pipes of the other house, then they will affect each other when pulling water. E.g. the last house in the chain will not get any water if the first one pulls water, because the pipe capacity is used by the first house. Similar situation with electrical current.

  • \$\begingroup\$ Thank you Stefan :) your example made things clear. Accepted it as the answer \$\endgroup\$ – Harini Chandran Apr 2 '18 at 14:03

If you’ve got several chips that have a ground connection, don’t run a long wire directly from x to y’all ground pin, and from y to z’s ground pin. Instead, pick a point to connect all of the grounds together, and then run separate wires from that point to x y and z.


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