2. misc-audio
  3. 189542-76197

How can I measure the noise on my AC mains with a 2ch oscilloscope?

I’m not an EE so although I have some nice test equipment I need help. Here is the problem, the AC Mains are 120 vac but I’m trying to measure the noise on the AC signal , millivolts. I’d like to answer two questions how bad is my power and second  does my isolation transformer make a difference.

 

thanks for the help 

badbruno
badbruno OP
28 posts
 

Thanks you sharing your insights and perspective. I never thought of this as being a Hack… hmm 

yes the AC into the OScope is an issue even with my 10x or 100x probs.

Can you share some leads to these “on line resources” ?

Hey OP? 

thanks 

 

badbruno OP
28 posts
 

Jason you make a good point !

Post removed 
carlsbad2's avatar
carlsbad2
1,365 posts
 

OP.  While that is a nice experiment, it isn't really necessary.  Nobdy has good quality power coming into their home today.  Too many non-synchronous loads on the line that mangle the sine wave.  My power generally runs 4% thd or so.  

I don't have a stand along o-scope.  My PSA P10 has a built in scope with fixed settings to measure it.  Here is a random graph:

 

badbruno OP
28 posts
 

Carlsbad2 - thanks for the graph. I’ve looked at my waveform and it’s clipped at the peaks and some junk on the wave too .  I’m really looking to see how well my power conditioner works. If we can agree that street power and house loads make it worse, but well designed gear will handle it, what was the reason you’re regenerating your power? Your PSA was an expensive investment?

 

 

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