Differential Probe for O'scope

Discussion in 'Test & Measurement Forum' started by cng2018, Jun 6, 2018.

  1. cng2018

    Thread Starter New Member

    Jun 6, 2018
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    Hello,

    I am new member. Can you help me a questiion?
    I have a Lecroy O'scope LC500, 4 chanels, 1GHz bandwidth, 1GS/s sampling rate. Bu I am looking for a differential Probes, but I don't know what type of Differential Probes should be suitable with my O'scope LC500?
    Would anyone give me idea how to select the Differential Probes to buy?
    Thanks for help.
    -Ken
     
  2. Hymie

    Active Member

    Mar 30, 2018
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    Such probes are quite expensive, when it might be possible to measure what you want using 2 probes and the difference function of the scope.

    If the circuit under test is not (and cannot) be referenced to the scope chassis – then the only option might be to use a differential probe (or given the cost, buy a class II scope).
     
  3. cng2018

    Thread Starter New Member

    Jun 6, 2018
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    Thanks for response. I will only use the differential probe for reducing the high voltage going to O'scope.
    What is class II scope, specific model?
    Thanks
     
  4. Hymie

    Active Member

    Mar 30, 2018
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    You do not need a differential probe to measure high voltages with a scope – you need a high voltage probe.

    That said, with a x10 probe, most scopes can measure into the kV range – what is the voltage you want to measure with the scope?
     
  5. danadak

    Well-Known Member

    Mar 10, 2018
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  6. cng2018

    Thread Starter New Member

    Jun 6, 2018
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  7. Hymie

    Active Member

    Mar 30, 2018
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  8. ebp

    Well-Known Member

    Feb 8, 2018
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    Differential probes come in different general types.

    There are moderate bandwidth types that are intended primarily for industrial work such as motor drives and other similar equipment that operates at "high" voltage with respect to the oscilloscope ground. They are fairly robust, easy to use and reasonably inexpensive. The common mode rejection is good at low frequency but quite poor at high frequency. The LeCroy ADP305 is such a probe.

    There are high-bandwidth types intended for circuitry operating at low voltage relative to the scope's ground. They are moderately delicate, rather difficult to use effectively, and have good high frequency common mode rejection. They can cost from around a thousand dollars to many thousands of dollars. The LeCroy AP033 looks like their low-end model and will be something in the range of $3-4000 US.

    Pico Technology has a range of reasonably priced diff probes. I believe their products enjoy quite a good reputation.
     
  9. Wuerstchenhund

    Member

    Aug 31, 2017
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    Being a bit more precise when describing what you have wouldn't hurt, because there never was a LeCroy "LC500". There was the LC Series, with various models with BWs from 500MHz to 1.5GHz and sample rates from 500MSa/s up to 8GSa/s. There was a LC534 which had 1GHz BW and 500MSa/s sample rate.

    The model of scope you have has a big impact on what probes actually make sense to buy.

    Your LeCroy scope has ProBus interface, so you want an active probe with the same interface. There are many active differential probes that are compatible and often go for little money on ebay. There's the AP033 (500MHz) and AP034 (1GHz), and there are the HFP1000/1500/2500 (the number is the BW in MHz). Both should be fully supported by the LC Series if you're running the latest firmware.

    The ADP035 is also compatible with the LC Series, according to LeCroy:
    http://teledynelecroy.com/probes/high-voltage-differential-probes/adp305
     
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