Hi Weston,
Thank you very much for making the project open.
I am wiling to ship one of our unit to you for free, so you know what we are doing.
Just send me your shipping address in PM or send me a message on
www.rogprobe.comWe are also using isolated DC/DC converter. Some more EMI testing to be done.
At high frequency I see about ~6dB/octave which I guess is partially due to coil skin effect/LP behavior of the coil but also partially due to the passive integrator.
Some measurements bellow for reference:
![RP8025 - inexpensive mini Rogowski Coil Current Probe](https://www.eevblog.com/forum/index.php?action=dlattach;topic=424295.0;attach=2134501;image)
RP8025 – Measured frequency response
![RP8025 - inexpensive mini Rogowski Coil Current Probe](https://www.eevblog.com/forum/index.php?action=dlattach;topic=424295.0;attach=2134507;image)
Ideal 400mApp 100KHz square wave current measurement
![RP8025 - inexpensive mini Rogowski Coil Current Probe](https://www.eevblog.com/forum/index.php?action=dlattach;topic=424295.0;attach=2134513;image)
Ideal 400mApp 1MHz square wave current measurement
![RP8025 - inexpensive mini Rogowski Coil Current Probe](https://www.eevblog.com/forum/index.php?action=dlattach;topic=424295.0;attach=2134519;image)
Ideal 400mApp 10KHz square wave. Due to low frequency cut-off the tops and bottoms are tilt.
![RP8025 - inexpensive mini Rogowski Coil Current Probe](https://www.eevblog.com/forum/index.php?action=dlattach;topic=424295.0;attach=2134525;image)
400mApp ideal 100KHz triangle wave current measurement
I have measured few coil samples we have manufactured with polyolefin heat shrink and they are more like ~1.76mm O.D. and they fit in-between of TO-220 pins.
Thank you very much for the FEP heat shrink suggestion I will test it.
I wanted to extend the frequency band towards the low frequency but with this design it seems to be tricky.
At the end I have decided to used your original Opams. I think you did a great job selecting them.
As a price my intention is we offer an inexpensive AC current probe for hobby usage rather than gaining bigger profit.
I am not sure if and how it will work.
Best Regards
Dimitar