I'm a newbie with the oscilloscope. I have a digital RIGOL with two probes.
I'm testing a simple 12V AC to 5V DC converter.
I'm trying to measure the effect of the 7805 on the DC signal in output and comparing this signal to the AC signal before the rectifier bridge.
If I connect the probes as you can see in the pictures I see sparkles (short circuit) on the GND probe of the AC line. This make me think that the the two probes of the oscilloscope have common GND.
So now I have two question:
Have I to connect only one GND of the probe to the GND of the circuit to study the signals properly?
What can I look to understand if the output signal is "clean" (no ripple, no big oscillation)? Have I to select AC coupling in the oscilloscope and see Vrms, frequency, ecc...?
Sorry to bother you with this very simple question but I see that using the oscilloscope properly is difficult.