Very good job describing why you need to use as short ground as possible. Most do not understand how important this is for debugging a circuit and will chase the wrong problem.
As always: excelent! I still haven't seen all his videos (but probably most of them), and, for sure, Alan is doing great quality stuff here in RUclips. Thank you, Alan!
GEAT! This video should be mandatory for all Electronics courses. I've worked with veteran BSEEs, MSEEs and PhDs who would chase phantom issues for days due to improper probing! RF guys tend to know, Power supply guys, 'kinda and Logic guys not at all.
@hardstyle905 They design with simulators which have lovely Tr and Tf illustrations and then let some lowly tech try to figure out why there are glitches, then blame the manufacturing department.
@hardstyle905 I've worked with many EE Interns and new graduates. Unfortunately in the last 20+ years this stuff is not taught at all, and there is zero "hands-on" in the coursework. Worse yet, very few Perfessors under 50 even know how to properly use an oscilloscope. 20-30 years ago I would tell students to buy and build at least 3 Heathkits, but that is no longer an option.
@hardstyle905 This is weird. Your comment came through on my notifications, but is not on the actual video here. I'm guessing that the YT policing algorithm has grabbed it from "publication" here to analyze it, and since it is quite long has not yet digested it. I was going to paste it here, but I think it would have the same result. So... lets see my next comment!
@hardstyle905 It's evident that practical, hands-on experience plays a crucial role in certain areas of learning. Take PCB design, for instance. Despite mastering the theory - the significance of short leads, ground planes, and parasitics - I encountered a steep learning curve when I started creating actual PCBs. Interestingly, a senior engineer once inspected my work and remarked on the excessive stray inductance, particularly for applications involving high-frequency and high-power switching. In retrospect, it's almost amusing. I inadvertently created a significant ground return loop and overlooked lead trimming for through-hole components. It wasn't that I lacked the knowledge of 'short traces'; rather, I needed the practical insight to comprehend the exact implications. Experience gradually provided that insight. I still find value in prototyping on breadboards or veroboards, though my perspective has evolved. Now, I intuitively understand that every millimeter equates to a nanohenry of inductance. It's fascinating how just a few nanoseconds of a 10-amp current through a 20-nH inductor can lead to considerable voltage drops, potential ringing issues, and ultimately, substantial power loss or even damage to the switching components. Reflecting on this, I can't help but admit that lacking proficiency in using essential tools like an oscilloscope, especially in academic roles, is a more critical concern. It's a safety and effectiveness issue that warrants serious attention.
An eye opening lesson on an important topic which a novice (like me) could (and did) completely overlook! Can't thank you enough for including videos on "The Basic's", among the other advanced subjects!
You made a good point Alan, few enthusiasts (including me) consider the ground connection as a routine problem in test procedures. This video was a well timed reminder. of the problem. Thank you.
thanks for clarifying this. Although I had some idea what they were, I've always wondered what the exact purpose of those extra accessories that came with my Tek probes were for.....now I know! - Thanks a lot for posting.
Great video as always! Can you do video about oscilloscope probes? How to choose a probe for your oscilloscope model, capacitance of probes, impedance, how probe affects the device under test ,what is the compensation of probe ...? I think it's an important issue and it is important to choose the right probes. Thank you again for this wonderful tutorials! Excuse my bad English!!!
Biomedical Equipment requires to measure the equipment chassis ground resistance to the ground terminal of the AC cord. Also to measure the Leakage current from the equipment chassis ground to the AC cord HOT terminal. They use a lab test gear called a "Safety Analyzer" to measure the Leakage Current and Ground Resistance. If you didn't have this Safety Analyzer how would you measure the Leakage current? I'm guessing its AC leakage current or DC leakage current? The Leakage current is caused by what the AC power transformer or the power supply filters. If you're measuring the Leakage current of a unit under test what is causing this leakage current from the AC hot lead to the Chassis ground?
Great video! Thanks! You mention that the inductance depends on the length of the wire until the ground and the signal are together in the probe. I can intuitively accept that very well but I cant quite put a name on the physical phenomena: why does the ground stop acting like an inductor when it is closed to the signal? Is it for the same reason that coax does not act as an antenna?
Thanks Alan for another good tutorial. Just curious- sometimes there is no easily accessible ground near the place where I am testing. Would putting a ferrite bead/core around the 6inch ground lead help?
How do you prevent Eddy currents? Because ground loops causes Eddy currents which is current that can't be sink to ground. Besides ground loops what causes Eddy currents? And why are Eddy current considered bad? Because Eddy current causes bad signal to noise ratio?
Another fabulous video. You'd make a good professor. I love your use of a tripod in this video! I was thinking: what effect would a capacitor of the appropriate value have if placed in series with the ground lead. Wouldn't that cancel out the inductive reactance of the lead, leaving only an equivalent series resistance?
Anyone else rapidly pressing spacebar to try and catch that artifact at 4:40? Finally caught the bugger at 4:44. It's like a zebra hole-punch clipping.
Good information. Was wondering if there is some way to shorten ground lead on a "typical" (low end = $400 to $1000 oscilloscope) scope probe? If one wanted to make shorter leads where would they get the connectors (ring connector to probe)? I don't see these for sale on their own.
+Digger D Never mind ;) I disassembled one of my probes and checked out your other video on this #111 - Another day where I learned something - thanks ;)
Thanks for sharing. Does the edge ringing due to short rise/fall time also caused by a long coaxial cable of the probe? I wonder if transmission line on the probe cable contributes to the ringing.
Hello, great video again! Now, I now I have a lot a questions but I red a lot of information recently and I need tips to organized it, so please bear with me a little. What bandwidth is your scope? Is the saw ringing amplitude value influenced by the scope bandwidth? For ex. a 50 Mhz scope would see a 50 Mhz oscillation with 0.707 of its original amplitude (theoretically) ? Are those ringings some kind of reflections signal, because of unmatched impedance? So practically the ground lead is a LC tank oscillator?
Interesting video. I ran across a situation yesterday, where the sine wave was slightly jumping on the oscilloscope. I inadvertently touched the ground lead and the jumping stopped. I wonder if this falls under the same situation that you demonstrated?
It is likely that the ground lead was acting as an antenna, picking up another interfering signal that was being added to your result. This is another good reason to keep the ground leads and loop area short/small.
Thanks for another interesting video. I have a question: What about multi-channel scopes. Should each channel be grounded (current loops?) or is it better to connect just one ground shared by all channels.
+Ratz Alter Each probe should be grounded - otherwise the effective ground lead length would be very long! Of course, this means that all circuits that you are probing simultaneously must share a common ground. If you have seperate "analog" and "digital" grounds that are common at some point, this will all be OK since the inductance between the two probe ground leads will be high enough to keep these planes from interacting.
What probe model number is that? I heard 300 mhz speed..a P6131 maybe? I bought two NIB Tek P6121 good to 100 mhz for my 2230.. I'm convinced good ones are not cheap. I can do the twisted wire trick if I need to.
Hello I purchased 2 sope probes new they are 200 mh says seller just wondering is there a way to test these to see if they are 200 I still am new to using a scope Thankyou very much
Hi Is it possible to measure the noise a cable pickups up , even when there is no voltage going to it? this to see let say cable for PV systems, to see how good they are in therms of shielding. Or are behave like a big antenna , i heard of people who live near a airport of military that some time when plane fly over the systems shut off , (rader problem ) or bad cable's? Any way how do you test cables on a oscilloscope
Hi Alan, question - there are some cheap function generators for sale, kits, etc. Some don't have BNC connections, just screw connections. So, what kind of probe would you recommend, if any? Is this a 300 ohm thing? Or, would you recommend connecting a female bnc to the function generator and then using a standard coaxial BNC o'scope probe? Or maybe your advice is forget the cheap function generator? :) 73, KM5L
I'd probably wire in a female BNC. These cheap generators can be useful for low frequency work, just don't expect a lot of stability or low distortion.
What would you recommending using to measure and test connectivity of various switches and jacks because of the different materials used for metals of various switches on the contacts and jack metal materials of the potting and coating which will decrease the connectivity. The problem is how can you measure the connectivity because microohms or milliohm meters can't measure the connectivity of the jacks metal materials and the switch contacts materials used. The connectivity measures how well its passes through the metal materials but what meter measure this?
@@w2aew I'm not sure if a 4 wire resistance measurement will be able to measure the conductivity value of switches and jacks because its of the metal materials used and the coating the switches and jacks. There must be a meter that measures conductivity across 20hz to 20khz. To compute for the conductivity you take the inverse reciprocal of the milliohm measurement?
@@w2aew Most DVM meters measure voltage but it doesn't tell you if the voltage is unregulated or regulated, how can an electronic tech know if the voltage being measured is regulated or unregulated? not using the schematics. There must be a DVM meter or Oscope that can know the differences between an unregulated voltage compared to a regulated voltage but I can't tell when looking at the displayed AC voltage or DC voltage on the Oscope, how can you tell?
@@waynegram8907 You can't tell if a voltage is regulated by just a simple measurement. If you can't see a schematic, then one way to tell is to change the load that this voltage is driving and see how much the voltage changes.
@@w2aew Using a Low Impedance setting on the DVM meter can test Unregulated voltages? if the in-circuit unregulated voltage is +12vdc and you measure the unregulated +12vdc using the low impedance setting on the DVM meter it will drop the unregulated +12vdc voltage decreasing it?
I made a probe using coaxiel cable, needle and bnc connector. I am grounding the cable from the BNC's compressed metal ring with a crocodile, There is higher noise then the classical probes like yours. Is it all beacuse of the grounding ? Why ?
What you've described is a 1x probe, which adds considerable capacitance to the circuit under test. You may want to review my video on the basics of 1x and 10x probes: Basic 1X and 10X Oscilloscope Probe tutorial
Very informative video, thanks :) I got a tip locating sleeve along with my oscilloscope probe. I am unable to figure out when and where to use this tip locating sleeve... Can you please tell me if you have any idea about it ?
I'm not sure what you mean by "tip locating sleeve". It might be an insulating adapter that makes it easier to probe the pins on an IC without shorting multiple pins with the probe tip.
***** You can also see 2 pairs of 'Tip locating sleeves' in this image : www.pennybuying.com/media/catalog/product/cache/1/image/8da1cf41253d9952b7c40c20a61ca483/b/3/b300a_3__1.jpg
Ravi Ranjan Yes. The ones with the little plastic "nubs" adjacent to the probe tip hole are used to probe the pins of a DIP package or connector. The plastic nubs fit between the pins, thus helping to keep the probe tip centered on the pin that you're probing, keeping it from slipping off and shorting against an adjacent pin. The ones without nubs adjacent to the probe tips are simply insulators that cover the ground ring on the probe tip so that it doesn't accidentally short against a component lead, etc.
You have a 200 milla-hertz scope and a signal generator that goes beyond 200 milla-hertz, and you still don't realize that a lowercase 'm' (10^-3) signifies 9 orders of magnitude less than a capital 'M' (10^+6), when placed before a standard S.I. unit? I point this out to help you, and I mean no harm: Use a capital "M" for 'Mega'
Okay I'm going to guess okay, that you're from the north, okay it's just a guess, okay but I'm guessing Okay. But that's okay. Because I say okie dokie a lot.
Excellent--I would not have guessed how much difference the ground lead length makes. Thank you.
Very good job describing why you need to use as short ground as possible. Most do not understand how important this is for debugging a circuit and will chase the wrong problem.
As always: excelent! I still haven't seen all his videos (but probably most of them), and, for sure, Alan is doing great quality stuff here in RUclips. Thank you, Alan!
GEAT! This video should be mandatory for all Electronics courses. I've worked with veteran BSEEs, MSEEs and PhDs who would chase phantom issues for days due to improper probing! RF guys tend to know, Power supply guys, 'kinda and Logic guys not at all.
@hardstyle905 They design with simulators which have lovely Tr and Tf illustrations and then let some lowly tech try to figure out why there are glitches, then blame the manufacturing department.
@hardstyle905 That's my experience in over 40 years. Yours may differ.
@hardstyle905 I've worked with many EE Interns and new graduates. Unfortunately in the last 20+ years this stuff is not taught at all, and there is zero "hands-on" in the coursework. Worse yet, very few Perfessors under 50 even know how to properly use an oscilloscope. 20-30 years ago I would tell students to buy and build at least 3 Heathkits, but that is no longer an option.
@hardstyle905 This is weird. Your comment came through on my notifications, but is not on the actual video here. I'm guessing that the YT policing algorithm has grabbed it from "publication" here to analyze it, and since it is quite long has not yet digested it. I was going to paste it here, but I think it would have the same result. So... lets see my next comment!
@hardstyle905 It's evident that practical, hands-on experience plays a crucial role in certain areas of learning. Take PCB design, for instance. Despite mastering the theory - the significance of short leads, ground planes, and parasitics - I encountered a steep learning curve when I started creating actual PCBs. Interestingly, a senior engineer once inspected my work and remarked on the excessive stray inductance, particularly for applications involving high-frequency and high-power switching. In retrospect, it's almost amusing. I inadvertently created a significant ground return loop and overlooked lead trimming for through-hole components. It wasn't that I lacked the knowledge of 'short traces'; rather, I needed the practical insight to comprehend the exact implications. Experience gradually provided that insight.
I still find value in prototyping on breadboards or veroboards, though my perspective has evolved. Now, I intuitively understand that every millimeter equates to a nanohenry of inductance. It's fascinating how just a few nanoseconds of a 10-amp current through a 20-nH inductor can lead to considerable voltage drops, potential ringing issues, and ultimately, substantial power loss or even damage to the switching components.
Reflecting on this, I can't help but admit that lacking proficiency in using essential tools like an oscilloscope, especially in academic roles, is a more critical concern. It's a safety and effectiveness issue that warrants serious attention.
I didn't know how much the ground cables had an impact on signal integrity until just now. Great video. Thank you!
An eye opening lesson on an important topic which a novice (like me) could (and did) completely overlook! Can't thank you enough for including videos on "The Basic's", among the other advanced subjects!
You made a good point Alan, few enthusiasts (including me) consider the ground connection as a routine problem in test procedures. This video was a well timed reminder. of the problem. Thank you.
I would have not thought about that. Another excellent video. Thanks.
73
This is really damn helpful! I knew the connection affects the frequency response but never have a chance to quantify the effect like this!
This video has serious grounds. Thank you so much.
Well, I didn't know that. Thanks for the continuing education!
An important lesson. Good job!
As a noob, I have learned so much from your videos. Thank you, and keep it up :)
Excellent demonstration. Your video's always are the best. I certainly learn a lot from them. Thanks.
Amos
A very good demostration, Thank you very much, it helped me a lot!
Well done!
Thank you for your great videos.
Btw, in a pinch, you can create a ground spring by bending/cutting the spring inside an ordinary ballpoint pen.
good video on an often overlooked aspect of scopes
thanks for clarifying this. Although I had some idea what they were, I've always wondered what the exact purpose of those extra accessories that came with my Tek probes were for.....now I know! - Thanks a lot for posting.
Great video
❤️
I just wanted you to know that I enjoy your videos and learned from them.
Keep on with good work, it is appreciated. -WB5UGD
thank you!
This was a big help. Thank you.
thank you for the detailed explanation!!! It helped me a lot. :)
I had no clue! Thank you
Good video mate
Great video as always! Can you do video about oscilloscope probes? How to choose a probe for your oscilloscope model, capacitance of probes, impedance, how probe affects the device under test ,what is the compensation of probe
...? I think it's an important issue and it is important to choose the right probes.
Thank you again for this wonderful tutorials!
Excuse my bad English!!!
Very good and helpful- Thank you for sharing
Brilliant 👏
Everything works great!
I think a differential probe might help to avoid ringing.
Excellent vid,ohmkay, I subscribed,ohmkay, looking foward to viewing the other 67 vids...ohmkay.
Thanks...really, It wasn't in my capacity to resist.
Very very good video
Thanks
내용 아주 좋습니다. 감사^^
Thank you (and thank you to google translate).
Biomedical Equipment requires to measure the equipment chassis ground resistance to the ground terminal of the AC cord. Also to measure the Leakage current from the equipment chassis ground to the AC cord HOT terminal. They use a lab test gear called a "Safety Analyzer" to measure the Leakage Current and Ground Resistance. If you didn't have this Safety Analyzer how would you measure the Leakage current? I'm guessing its AC leakage current or DC leakage current? The Leakage current is caused by what the AC power transformer or the power supply filters. If you're measuring the Leakage current of a unit under test what is causing this leakage current from the AC hot lead to the Chassis ground?
thanx,,, now we know how to expose tip
Great video! Thanks!
You mention that the inductance depends on the length of the wire until the ground and the signal are together in the probe.
I can intuitively accept that very well but I cant quite put a name on the physical phenomena: why does the ground stop acting like an inductor when it is closed to the signal?
Is it for the same reason that coax does not act as an antenna?
Very cool video, okay. :) :)
Yes I have a 200 mhz scope and a signal generator that goes beyond 200 mhz its a motorola fm generator used for communication equipment
thanks
Thanks Alan for another good tutorial.
Just curious- sometimes there is no easily accessible ground near the place where I am testing. Would putting a ferrite bead/core around the 6inch ground lead help?
How do you prevent Eddy currents? Because ground loops causes Eddy currents which is current that can't be sink to ground. Besides ground loops what causes Eddy currents? And why are Eddy current considered bad? Because Eddy current causes bad signal to noise ratio?
Another fabulous video. You'd make a good professor. I love your use of a tripod in this video!
I was thinking: what effect would a capacitor of the appropriate value have if placed in series with the ground lead. Wouldn't that cancel out the inductive reactance of the lead, leaving only an equivalent series resistance?
Anyone else rapidly pressing spacebar to try and catch that artifact at 4:40? Finally caught the bugger at 4:44. It's like a zebra hole-punch clipping.
Weird - don't know where that came from!
Good video, Maybe probes for digital frequencies greater than 10 mhz would be good to find.
Good information. Was wondering if there is some way to shorten ground lead on a "typical" (low end = $400 to $1000 oscilloscope) scope probe? If one wanted to make shorter leads where would they get the connectors (ring connector to probe)? I don't see these for sale on their own.
+Digger D Never mind ;) I disassembled one of my probes and checked out your other video on this #111 - Another day where I learned something - thanks ;)
Thanks for sharing. Does the edge ringing due to short rise/fall time also caused by a long coaxial cable of the probe? I wonder if transmission line on the probe cable contributes to the ringing.
PRETTY GOOD
cool !!!
Hello, great video again! Now, I now I have a lot a questions but I red a lot of information recently and I need tips to organized it, so please bear with me a little. What bandwidth is your scope? Is the saw ringing amplitude value influenced by the scope bandwidth? For ex. a 50 Mhz scope would see a 50 Mhz oscillation with 0.707 of its original amplitude (theoretically) ? Are those ringings some kind of reflections signal, because of unmatched impedance? So practically the ground lead is a LC tank oscillator?
Hi
Can the shield of probe have any inductance?
good day sir what happen the scope if positive probe tip touch to ground ?
Interesting video. I ran across a situation yesterday, where the sine wave was slightly jumping on the oscilloscope. I inadvertently touched the ground lead and the jumping stopped. I wonder if this falls under the same situation that you demonstrated?
It is likely that the ground lead was acting as an antenna, picking up another interfering signal that was being added to your result. This is another good reason to keep the ground leads and loop area short/small.
Ok, thanks. I guess I don't yet know how those ferrite beads really work, yet ...
Thanks for another interesting video.
I have a question: What about multi-channel scopes. Should each channel be grounded (current loops?) or is it better to connect just one ground shared by all channels.
+Ratz Alter Each probe should be grounded - otherwise the effective ground lead length would be very long! Of course, this means that all circuits that you are probing simultaneously must share a common ground. If you have seperate "analog" and "digital" grounds that are common at some point, this will all be OK since the inductance between the two probe ground leads will be high enough to keep these planes from interacting.
What probe model number is that? I heard 300 mhz speed..a P6131 maybe?
I bought two NIB Tek P6121 good to 100 mhz for my 2230..
I'm convinced good ones are not cheap. I can do the twisted wire trick if I need to.
Hello
I purchased 2 sope probes new they are 200 mh says seller just wondering is there a way to test these to see if they are 200 I still am new to using a scope
Thankyou very much
M'kay!
Hi
Is it possible to measure the noise a cable pickups up , even when there is no voltage going to it?
this to see let say cable for PV systems, to see how good they are in therms of shielding.
Or are behave like a big antenna , i heard of people who live near a airport of military that some time when plane fly over the systems shut off , (rader problem ) or bad cable's?
Any way how do you test cables on a oscilloscope
Hi Alan, question - there are some cheap function generators for sale, kits, etc. Some don't have BNC connections, just screw connections. So, what kind of probe would you recommend, if any? Is this a 300 ohm thing? Or, would you recommend connecting a female bnc to the function generator and then using a standard coaxial BNC o'scope probe? Or maybe your advice is forget the cheap function generator? :) 73, KM5L
I'd probably wire in a female BNC. These cheap generators can be useful for low frequency work, just don't expect a lot of stability or low distortion.
What would you recommending using to measure and test connectivity of various switches and jacks because of the different materials used for metals of various switches on the contacts and jack metal materials of the potting and coating which will decrease the connectivity. The problem is how can you measure the connectivity because microohms or milliohm meters can't measure the connectivity of the jacks metal materials and the switch contacts materials used. The connectivity measures how well its passes through the metal materials but what meter measure this?
Check out my video on 4-wire resistance measurements, which is the right way to make very low resistance measurements.
@@w2aew I'm not sure if a 4 wire resistance measurement will be able to measure the conductivity value of switches and jacks because its of the metal materials used and the coating the switches and jacks. There must be a meter that measures conductivity across 20hz to 20khz. To compute for the conductivity you take the inverse reciprocal of the milliohm measurement?
@@w2aew Most DVM meters measure voltage but it doesn't tell you if the voltage is unregulated or regulated, how can an electronic tech know if the voltage being measured is regulated or unregulated? not using the schematics. There must be a DVM meter or Oscope that can know the differences between an unregulated voltage compared to a regulated voltage but I can't tell when looking at the displayed AC voltage or DC voltage on the Oscope, how can you tell?
@@waynegram8907 You can't tell if a voltage is regulated by just a simple measurement. If you can't see a schematic, then one way to tell is to change the load that this voltage is driving and see how much the voltage changes.
@@w2aew Using a Low Impedance setting on the DVM meter can test Unregulated voltages? if the in-circuit unregulated voltage is +12vdc and you measure the unregulated +12vdc using the low impedance setting on the DVM meter it will drop the unregulated +12vdc voltage decreasing it?
I made a probe using coaxiel cable, needle and bnc connector. I am grounding the cable from the BNC's compressed metal ring with a crocodile, There is higher noise then the classical probes like yours. Is it all beacuse of the grounding ? Why ?
What you've described is a 1x probe, which adds considerable capacitance to the circuit under test. You may want to review my video on the basics of 1x and 10x probes: Basic 1X and 10X Oscilloscope Probe tutorial
Very informative video, thanks :)
I got a tip locating sleeve along with my oscilloscope probe. I am unable to figure out when and where to use this tip locating sleeve... Can you please tell me if you have any idea about it ?
I'm not sure what you mean by "tip locating sleeve". It might be an insulating adapter that makes it easier to probe the pins on an IC without shorting multiple pins with the probe tip.
***** www.seeedstudio.com/depot/images/product/BNC%20Oscilloscope_01.jpg
***** You can also see 2 pairs of 'Tip locating sleeves' in this image :
www.pennybuying.com/media/catalog/product/cache/1/image/8da1cf41253d9952b7c40c20a61ca483/b/3/b300a_3__1.jpg
***** i00.i.aliimg.com/img/pb/921/617/508/508617921_629.jpg
Ravi Ranjan Yes. The ones with the little plastic "nubs" adjacent to the probe tip hole are used to probe the pins of a DIP package or connector. The plastic nubs fit between the pins, thus helping to keep the probe tip centered on the pin that you're probing, keeping it from slipping off and shorting against an adjacent pin. The ones without nubs adjacent to the probe tips are simply insulators that cover the ground ring on the probe tip so that it doesn't accidentally short against a component lead, etc.
your hands are green Dear Alan
You have a 200 milla-hertz scope and a signal generator that goes beyond 200 milla-hertz, and you still don't realize that a lowercase 'm' (10^-3) signifies 9 orders of magnitude less than a capital 'M' (10^+6), when placed before a standard S.I. unit? I point this out to help you, and I mean no harm: Use a capital "M" for 'Mega'
What about probe impedance? In your setup, are you using 1 Meg or 50 ohm?
I was using 10X passive probes, which have a 10Meg input impedance (low freq) and use a 1Meg scope input impedance.
One more thing they didn't show me at school.
effects.
genius
Thanks !
Okay I'm going to guess okay, that you're from the north, okay it's just a guess, okay but I'm guessing Okay. But that's okay. Because I say okie dokie a lot.