Products > Test Equipment
Micsig CP1003/CP503 100MHz/50MHz Current Probe
jonpaul:
Rebonjour a tous:
Your questions re TEK CT and CMRR sparked my curiosity.
I unearthed my collection of CT and DC hall TEK probes, circa 1980s..1990 at ham fleas in SV, epay, since 2000 and (sadly) ham friends silent keys.
For SMPS, arc lamp ballast, pulsed power, R&D, consulting and magnetics design.
With HP LCR meter 4332A, with a short insulated wire stub, 3 pF range, zero out wire stub, 20..50 mm
Cap Probe return/body to wire.
P6022 0.75pF (AC passive, LF 3 db 8.5 kHz)
p6021 0.85 pF (AC passive, LF 3 db 450 Hz)
P6302 1.0 pF (active hall DC-50 MHz)
P6303 0.58 pF (active hall 100A huge gun )
Conclusion: CMRR is not an issue, external Faraday shield unneeded.
stray C of test setup and DUT will swamp the under 1 pF C current wire ><probe return.
TEK has grounded the metal shell or shield of the probe CT and Hall device so a built in Faraday shield.
Your thoughts appreciated!
Have an ABSOLUTELY FANTASTIC day,
Jon
PS:
Probe size relates to core area, thus sensitivity and LF /HF rolloff point.
For very AC only we use TEK P6021 and much smaller TEK P6022
PPS: Yokogawa current probes are also excellent but the probe power is a proprietary pinout, +/- 12 V on a 4 pin Lemo.
PartialDischarge:
--- Quote from: jonpaul on January 26, 2023, 12:51:47 am ---In 55 yrs we never had a problem with a current probe CMRR.
--- End quote ---
Never had problems because as you mention you did avoid it by measuring low side. Also nowadays stacked or multilevel topologies are quite common which was not the case 20 or more years ago.
--- Quote from: jonpaul ---Conclusion: CMRR is not an issue, external Faraday shield unneeded.
--- End quote ---
Wrong conclusion.The capacitances you mention are only relevant to calculate how much current goes into the current probe from your circuit (loading purposes) but says nothing about how the measure will be affected.
Of the probes listed I only saw the RS having CMRR data, and it is not bad, but extremely bad, only quoted to 20KHz, I can imagine at 1MHz is it like 20dB.
thaamike:
Any luck getting these probe for the nice price ?
EEVblog:
--- Quote from: thaamike on February 12, 2023, 01:01:27 pm ---Any luck getting these probe for the nice price ?
--- End quote ---
I've just asked again for the sample.
EEVblog:
--- Quote from: EEVblog on February 12, 2023, 10:07:57 pm ---
--- Quote from: thaamike on February 12, 2023, 01:01:27 pm ---Any luck getting these probe for the nice price ?
--- End quote ---
I've just asked again for the sample.
--- End quote ---
They got back to me. The R&D team are all working on the isolated probe and have no time to finish the current probe :o so there will be delays.
Sounds like they think the isolated fibre optic probe will overtake the traditional high voltage probe, they want to know if I'm interested in getting one.
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