Help me about oscilloscope ?

[Nhan95]

I want to observe the signal on resistor and capacitor in this circuit by oscilloscope. But if I connect the probe of channel 1 and 2 like the picture, the inductor will be short circuit. How do I do in this case ? Help me. thank you so much Assume we don't swap the component.

[nctnico]

The grounds of the probes are connected together and to earth (the ground wire in the mains lead) on 99.9% of the oscilloscopes so there is your problem.

[mauroh]

Swap C1 and L1, the circuit will not change.
Leave CH1 as is and move up CH2 across C1
Select Invert CH2 on the oscilloscope
Now you have the ground connected toghether and the signal of R1 and C1 on the scope without short circuits

If you have a 4ch oscilloscope you can use 3 channels and the math function without swapping C1 and L1

Mauro

[Brumby]

I was going to suggest something - but I like this idea much better...

Swap C1 and L1, the circuit will not change.
Leave CH1 as is and move up CH2 across C1
Select Invert CH2 on the oscilloscope
Now you have the ground connected toghether and the signal of R1 and C1 on the scope without short circuits

If you have a 4ch oscilloscope you can use 3 channels and the math function without swapping C1 and L1

Mauro

[alsetalokin4017]

Don't forget that in the "real world" the BNC shields of the Function Generator's output jacks are also likely to be connected to the Mains Ground and hence also connected to the Scope Probe grounds through the mains power cords.

[mauroh]

Good point alsetalokin4017, I think the easiest way is to rearange again the circuit moving R1 close to C1.
Now CH1 will see the wave form across R1 and using the marh function, the difference CH2-CH1 will be the signal on C1.

Don't know if Nhan95 is still interested in this....

Mauro