- #1

KyleGranger

- 37

- 2

- TL;DR Summary
- I am trying to understand different ratings on a differential probe

Hi,

I am looking at a Micsig DP2003 high voltage differential probe. It's rated for 5.6 kV differential voltage. I understand that the differential votlage is measuring across two terminals which can be floating (not referenced to GND). The specs say it is rated for 1 kV common mode voltage, but I don't understand that. I thought the common mode voltage was difference in voltage between one terminal being measured and GND. I don't think my understand of this is right because if so, how would you ever measure >1 kV with your scope referenced to GND? If this is correct, does that mean I would have to float my scope to truly measure >1 kV differential?

Assuming my understand is incorrect, how do I determine the maximum voltage that I can measure? For instance, let's say that I have 10 capacitors in series with 2 kV across each. I would have a 20 kV bus. If I wanted to measure the voltage across the top capacitor, it would only have a differential voltage of 2 kV so would be fine by the DM voltage spec. But wouldn't the CM voltage be 20 kV and blow up? What's the highest cap that I can measure in this 10 capacitor string using this specific probe? A link to this probe with specs is below.

https://www.amazon.com/dp/B07DKT61LD/?tag=pfamazon01-20

I am looking at a Micsig DP2003 high voltage differential probe. It's rated for 5.6 kV differential voltage. I understand that the differential votlage is measuring across two terminals which can be floating (not referenced to GND). The specs say it is rated for 1 kV common mode voltage, but I don't understand that. I thought the common mode voltage was difference in voltage between one terminal being measured and GND. I don't think my understand of this is right because if so, how would you ever measure >1 kV with your scope referenced to GND? If this is correct, does that mean I would have to float my scope to truly measure >1 kV differential?

Assuming my understand is incorrect, how do I determine the maximum voltage that I can measure? For instance, let's say that I have 10 capacitors in series with 2 kV across each. I would have a 20 kV bus. If I wanted to measure the voltage across the top capacitor, it would only have a differential voltage of 2 kV so would be fine by the DM voltage spec. But wouldn't the CM voltage be 20 kV and blow up? What's the highest cap that I can measure in this 10 capacitor string using this specific probe? A link to this probe with specs is below.

https://www.amazon.com/dp/B07DKT61LD/?tag=pfamazon01-20