I am trying to rule out power supply noise bleeding into my circuitry, so as a side task, I want to verify how good my power supplies are. I found this link but I would like someone to verify I did the measurements and calcs correctly:

https://electricalbaba.com/ripple-factor-definition-formula-derivation/

Step 1- Used a 5.5 digit DMM, and measured the DC ouput. For this example, it measured: 12.11 VDC.

Step 2- Used a 5.5 digit DMM and verified with a scope the the A/C component which measured: 230uV rms. Quite low me thinks.

I calculated the ripple factor (not percentage):

Answer for Y=.99999999918

So in the article it says to convert the factor to %, simply multiply by 100. Okay I did...

So now: 99.999999918 %

So that is telling me my ripple is 99.99.........%? I don't think so, it most likely tells me that the percentage is that much in DC.

Now I have to admit in my calculations, on the top line of the equation,

__the number comes out negative,__so I square rooted the

**absolute value**

Where did I go wrong? How do I calculate the actual ripple in percent?

Help very much appreciated.