Thnx guy's to pointing me out with nice tips.
I have also a handheld battery powered two channel 70MHz scope too.
Probably I will use this handheld scope for this measuring.
Im not new in the feel of scoping, I use it every day for small DC project and repair, but I have not so much experience with main AC
measuring. I'm also familiar with the risk of scoping the main voltage.
I never bought a differential probe cos I deal very less with high voltage, and when I have to then I use two probes with the MATH function to do the job.
But now I saw laying around an old Nokia 3310 phone charger, that one with a transformer in there.
The coils are completely separated from each other, practically galvanic separation.
Before I dropped in recycling bin I come a cross in mind to make a sort of tool for me.
To measure such of signals, even they are not precise, they are probably usable for rough measuring in some situation.
Here is a picture how I see the setup.
I can't figure out a situation how could I touch with my probe any live point to short out it.
The only common point is the alligator clip and earth/neutral.
I put an
Ix variable on the picture, where could go possible some current in some case, but hey!
only if the primary side is shorten out, and than should blow the main fuse and the shorten is cos due some other problems before the scope is connected.
Probably it would trip the main fuse at the moment the primary side of the T1 is connected to the main.