Do ALL Oscilloscope Probes Need Ground? - Workbench Wednesdays
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- čas přidán 11. 07. 2024
- When connecting multiple oscilloscope probes to a circuit, does each probe need to connect to ground? The short answer is: yes! But why? The long answer is: kind of. But (again) why? Because of the ground loop! Connecting ground shortens the ground loop, resulting in better measurements.
In this video, James shows what happens when you don't use proper ground connections, and he leaves you with a viewer challenge question! bit.ly/38Lf7uH
Workbench Wednesdays #47: What is Oscilloscope Bandwidth? bit.ly/3MEYBew
Application note from Tektronix: Fundamentals of Floating Measurements and Isolated Input Oscilloscopes bit.ly/3PJbjur
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#0:00 Welcome to Workbench Wednesdays
#0:40 Clip vs Spring
#2:22 (Passive) Probe Accessories
#3:48 Multiple GNDs
#5:59 Viewer Exercise
#6:39 Give your Feedback
#oscilloscope #oscilloscopeprobes #groundloop - Věda a technologie
I really enjoyed this explanation. Thank you
I just watched a video about this on EVblog, but I really couldn't get the gist of what he was saying. I love his videos, but your video was far more clear. Thank you, I probably would a blew my Rigol up if I hadn't watched this.
Thank you, James. Fantastic!!!
Terrific video. I have always used the ground, not because I was smart, but just because that's the way I was taught. I hadn't given much thought to the alternative. That was a really clear explanation/demonstration... thanks very much!
At an electronics manufacturer I worked at (pre-1984) I seem to recall seeing test point sockets on circuit boards that would accept the small Tektronix scope probe ends, sort of a small coaxial socket. Just by plugging the probe tip into the socket it would allow access to the test signal and provide a very good signal ground and shielding. This was when the smaller Tektronix probes were fairly new, and we also used the much larger ones as well.
Something to watch out for on multichannel scopes is probe cable lengths. Trying to determine signal time offsets can be misleading if you don't use probes with the same cable length. The signal propagation delay through different cable lengths will be noticeable, and worse at higher frequencies.
(If there's already a video about that on Element14, think of this as a reminder! ☺)
One of the nice things I've discovered about good active probes is that grounding is a lot less critical. A clip-wire ground can give as good SI as a spring on a passive. For my most critical probing though, I always use a differential probe.
6:06 circuit a is powered from a USB thus has ground loop completed. Circuit B is powered from an ac/dc adapter with isolated outputs.
i am thinking the same
+1 - The wallwart is completely isolated from any earthed path.
I could say you gave me a grounding in this subject😇
Nice video
I have a DSO and I recently moved into an older home. The receptacles do not have grounds. I am planning to rewire the house, but before then If I install a GFCI will this work for the grounds even though there technically will not be an actual ground? Also, will I be able to test with the DSO while using a bench power supply?
This is a "no equipment ground" situation. And I am not an electrician. However, if the scope and power supply are plugged into the same outlet, their reference should be the same.
hi can I use 150 MHz probe on 50MHz oscilloscope?
yes but you will only get a reading for 50mhz
I got an oscilloscope a year ago from Amazon prime and still haven’t really figured out what to do with it. But this is helpful and putting me in the right direction…. The power supply, one is using a dedicated power supply the other one is running off ethernet I think or USB
Follow the link above to see an explanation. (And while what you said is true, that does not explain the behavior.)
The one one the left has a isolated power source, possibly powered from a battery pack through a USB so no transformer. The circuit B is powered from a wall transformer and is on the same earth ground as the probes socket or power source.
one is a ac/dc and has no flux in power level. while the lan port power has a lot of other power flux.
Where dit that girl go? She's amazing!
I don't have an oscilloscope, I want to have one.
multiple 'gnd' at different potensials in system and you need to be very awake when attaching gnd probes.
There is a fortune (quite large) to be had by inventing cheap enough NON contact probes!
Spoiler you can if you understand what your doing and take that into consideration