multiple 'gnd' at different potensials in system and you need to be very awake when attaching gnd probes.

Spoiler you can if you understand what your doing and take that into consideration

I got an oscilloscope a year ago from Amazon prime and still haven’t really figured out what to do with it. But this is helpful and putting me in the right direction…. The power supply, one is using a dedicated power supply the other one is running off ethernet I think or USB

I have a DSO and I recently moved into an older home. The receptacles do not have grounds. I am planning to rewire the house, but before then If I install a GFCI will this work for the grounds even though there technically will not be an actual ground? Also, will I be able to test with the DSO while using a bench power supply?

I could say you gave me a grounding in this subject😇

Nice video

There is a fortune (quite large) to be had by inventing cheap enough NON contact probes!

I just watched a video about this on EVblog, but I really couldn't get the gist of what he was saying. I love his videos, but your video was far more clear. Thank you, I probably would a blew my Rigol up if I hadn't watched this.

The one one the left has a isolated power source, possibly powered from a battery pack through a USB so no transformer. The circuit B is powered from a wall transformer and is on the same earth ground as the probes socket or power source.

hi can I use 150 MHz probe on 50MHz oscilloscope?

Terrific video. I have always used the ground, not because I was smart, but just because that's the way I was taught. I hadn't given much thought to the alternative. That was a really clear explanation/demonstration... thanks very much!

Where dit that girl go? She's amazing!

At an electronics manufacturer I worked at (pre-1984) I seem to recall seeing test point sockets on circuit boards that would accept the small Tektronix scope probe ends, sort of a small coaxial socket. Just by plugging the probe tip into the socket it would allow access to the test signal and provide a very good signal ground and shielding. This was when the smaller Tektronix probes were fairly new, and we also used the much larger ones as well. Something to watch out for on multichannel scopes is probe cable lengths. Trying to determine signal time offsets can be misleading if you don't use probes with the same cable length. The signal propagation delay through different cable lengths will be noticeable, and worse at higher frequencies. (If there's already a video about that on Element14, think of this as a reminder! ☺)

one is a ac/dc and has no flux in power level. while the lan port power has a lot of other power flux.

I don't have an oscilloscope, I want to have one.

I really enjoyed this explanation. Thank you

One of the nice things I've discovered about good active probes is that grounding is a lot less critical. A clip-wire ground can give as good SI as a spring on a passive. For my most critical probing though, I always use a differential probe.

Thank you, James. Fantastic!!!

6:06 circuit a is powered from a USB thus has ground loop completed. Circuit B is powered from an ac/dc adapter with isolated outputs.