Products > Test Equipment
New MicSig/EEVblog DP10007 HV Differential Probe
nikifena:
I've got DP10013 but actually I prefer 10x/100x probe.
Just wondering about a simple hack with the input resistor dividers modifying the existing 50x/500x to 10x/100x diff probe.
Hydron:
DP10013 input divider is 500:1, followed by a buffer, then a 1x/10x gain output amp (gain switching done with a relay in a pretty janky way that doesn't give the most confidence in a good CMRR match between ranges, as there is only one trimmer for both).
To increase the gain the input divider low-leg R and C would need changing. There will be side effects to doing this, not the least of which would be a proportional reduction in the common mode input range (needs to stay within the bounds of the input buffer, which is the limiting factor).
Screws are also under the bloody sticker, asshole move there :--
EEVblog:
Has anyone measured the CMRR of the DP10007?
I measured well outside the spec at 10MHz, really obvious when directly compared with the HVP70 which has identical specs. Can anyone else confirm?
Micsig are investigating.
Hydron:
One of my DP10013s was well out of spec all the way from DC in one range (forget which but could check). Sent it in for an exchange.
Is yours out just at higher frequencies, or all the way from DC as well? I think I checked mine at DC by using a megger to apply ~500V of CM voltage (referenced to the BNC shield, plugged into a multimeter). Alternatively apply mains :P.
There is a single DC CMRR adjust pot and a trimmer cap for each divider leg in the DP10013 - if yours is OK at DC but not higher then it could be the latter being out.
Would certainly be interested in pics of the inside - wondering if it is different to the DP10013 or if they have just tweaked the divider/amplifier. Especially curious as to how they are doing the range switching (this is one of the weak points of the other one, and is how it was possible for one range to be out but the other OK). Would also be interested in a frequency response sweep.
Might be able to find my plots of DP10013 CMRR vs frequency if that helps.
EEVblog:
--- Quote from: Hydron on February 02, 2021, 11:58:00 am ---Is yours out just at higher frequencies, or all the way from DC as well? I think I checked mine at DC by using a megger to apply ~500V of CM voltage (referenced to the BNC shield, plugged into a multimeter). Alternatively apply mains :P.
--- End quote ---
Wasn't able to test with the simple setup I used. Problem at 10MHz, so I just informed them and left it at that for now.
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