Hi, I'm very stressed because I've a lab exam tomorrow. I wasn't aware I'd have to take it so I'm more than late when it comes to study for it. Furthermore I should be used to the oscilloscope while I had about 8 opportunities to "play" with it. Hence I have some questions : I've dealt with a digital oscilloscope, a tektronics 1000B I believe. It has 2 channels. Each probe have 2 crocodile clips. My first question is : Why when I use both probes (that I plug into both channels of the oscilloscope), I must not use the 4 crocodile clips? It could damage the oscilloscope, but how and why? I can use 3 crocodile clips with no problem, but my professor told us never to use the 4 of them. My second question is : Can someone explain me what is the connection to the ground? Why is it important? How can I do this with an oscilloscope? I never understood this part. Thank you very much!