Question
In the manual of your oscilloscopes you state:
If AC coupling is set, the attenuation of passive probes has no effect, and voltage is applied to the instrument with factor 1:1
Could you please explain the background of that?
No attenuation of passive probes with AC coupling
Answer
Attached is a principle circuit diagram of a passive probe. The capacitor marked in red shortens the 9 MOhm resistor at higher frequencies, so the 10:1 attenuation does not work.
