John, Let's say you used a 1 ohm resistor as we mentioned. A one amp current in your circuit would be viewed as a 1 volt, in phase waveform. This becomes your trigger source and your current waveform. But the 1 ohm might be too much of an influence on your total circuit so the smaller the resistance, the better, for sampling. As long as you can decrease the Volts/Division enough to trigger on and see it, you're fine. 1 ohm of resistance wouldn't make much of a difference if you have large values of inductive or capacitive reactance.
You would learn even more from your experiment if you substituted an audio generator for your voltage source and watched the effects while slowly sweeping the frequency.
Joe
