u/EGMxGolden

Hi there,

I want to measure the output ripple from a buck converter I designed. I watched an EEVBlog video on how to measure power supply ripple, and I was thinking I would adapt it for my use case.

However, the video suggests using a differential probe and measuring it that way, but I don't want to spend a few hundred bucks to buy a differential probe.

I then had an idea, which I want some advice on its credibility.

1. Hook up a normal probe to the power supply output (AC coupling)
2. Hook up a normal probe to the buck converter output (AC coupling)
3. Subtract the power supply ripple from the buck converter ripple

My main idea is that the ripple from the power supply would be transferred into the output from the buck. So if I subtract the power supply ripple, it would cancel out?