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Audio noise chasing: Oscilloscope on 120V AC (lemmy.ca)

submitted 1 week ago by [email protected] to c/[email protected]

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I just realized that I have never used an oscilloscope on anything over 50V DC. (There has never been a need, actually.)

The goal is to trace how noise generated by my PC GPU is propagating through the power circuit. As I don't want to start tossing in power filters at random spots, it would be nice to actually understand what is going on first.

TBH, measuring mains AC doesn't seem any different than any other measurement I would take, other than using a 1:100 scope probe. Are there any "gotchas" I should be aware of that would put my scope at risk?

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[–] [email protected] 4 points 1 week ago (1 children)

If you're using a mains powered 'scope, be aware that the ground on the probe may well be connected directly to the ground on the supply plug, so attaching it to anything mains powered could lead to a short cicruit, with all the associated unpleasantness. An issolated probe will avoid this issue, but they can be pricy, alternatively using a battery powered 'scope avoids the problem altogether.

[–] [email protected] 1 points 1 week ago

This gives me motivation to get a handheld scope just for my audio work as precision is not required. (The noise should produce fairly consistent patterns while the GPU is under heavy load, regardless of the scope precision.)

My risk tolerance for my scope is fairly low so thanks for taking the time to answer!