Author Topic: Scope probe with 50R resistor on end  (Read 930 times)

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Offline FaringdonTopic starter

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Scope probe with 50R resistor on end
« on: September 06, 2023, 07:18:16 pm »
Hi,
Does anyone have a scope probe with a 50R resistor on the end?..do you have a part number?......so that when in an offline smps, you are scoping the current sense input say, you dont suffer so much noise in the scope trace.
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Offline Kim Christensen

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Re: Scope probe with 50R resistor on end
« Reply #1 on: September 06, 2023, 07:30:31 pm »
Just get an inline / feedthrough BNC 50ohm termination if your scope doesn't have a 50ohm input option.
« Last Edit: September 06, 2023, 07:32:33 pm by Kim Christensen »
 
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Online tggzzz

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Re: Scope probe with 50R resistor on end
« Reply #2 on: September 06, 2023, 07:55:55 pm »
Hi,
Does anyone have a scope probe with a 50R resistor on the end?..do you have a part number?......so that when in an offline smps, you are scoping the current sense input say, you dont suffer so much noise in the scope trace.

As usual you give far too little information - presumably in an attempt to provoke chatter.

Since, apparently after a couple of decades, you still don't understand probes and safety, I suggest you read the references in
https://entertaininghacks.wordpress.com/library-2/scope-probe-reference-material/
There are lies, damned lies, statistics - and ADC/DAC specs.
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Offline Caliaxy

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Re: Scope probe with 50R resistor on end
« Reply #3 on: September 07, 2023, 12:26:02 am »
I’m quite sure there is no such a thing as an oscilloscope probe with a 50-ohm resistor at the oscilloscope end. The 50 ohm termination is only used for transmission lines (coaxial cables with 50 ohm characteristic impedance, in most cases that involve oscilloscopes), to prevent/minimize reflections that create artifacts on the screen. There are quite a few old (but still amazingly enlightening) Tektronix YouTube videos that address the issue. “The art of electronics” has an excellent chapter (or appendix, IIRC) on transmission lines.

Or maybe I don’t understand your question, case in which I apologize….
 
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Online tggzzz

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Re: Scope probe with 50R resistor on end
« Reply #4 on: September 07, 2023, 01:04:48 am »
Or maybe I don’t understand your question, case in which I apologize….

No need to apologise.

See the other threads treez/faringdon has started in the past couple of days - and years. They are all spur-of-the-moment questions that don't give sufficient information - and that's the charitable explanation.

However, since his behaviour is repeated even though quite a few people repeatedly point out the issue, some people are stating less charitable explanations.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 
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Offline jonpaul

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