This is a guide to use oscilloscopes

• The first rule to use an oscilloscope is: Don't use it unless you know the dangers of not knowing how to connect your probe grounds!

• Please look at this video to get an idea of the problem.

https://www.youtube.com/watch?v=xaELqAo4kkQ

• Every time you will use an oscilloscope, check again the grounds!!!
• Be very careful with laptops that don't have a third ground connector.
• Also be very careful with powerstrips that have the ground “removed”.
• Also read this:

https://www.eevblog.com/forum/projects/isolation-transformer-for-oscilloscope-how-to-wire-ground/msg101434/#msg101434