Thank You! You just saved me from trying to fix a local oscillator circuit that wasn't broke due to a low level reading on my scope with 1x probe at 36 mhz. I switched to x10 and there was my correct level! I really enjoy your videos.
excellent explanation, spot on. I had this explanation as a baby ship's radio officer in the late 80's in those days our radio and even some radar kit was lower then your average CPU FSB. - times change. This should really be compulsory stuff for new engineers yet as you say it's rarely mentioned, almost forgotten knowledge - tell us more Mr von Daniken !
Thanks Dave. When I first started work at an electronics repair centre (many, many years ago) my supervisor handed me a brand new scope, then switched both of my probes to x10 before handing them to me.
1X probes are not useless, they are very good for low voltage measurements, in order to keep the signal-to-noise ration as high as possible. Great video, though!
+electrocomm What he said was switchable x10 probes are useless as x1. You effectively have a hidden 470Ω resistor in series with your probe, and as shown your 'low voltage signal' will sink into the mud of noise @ 10MHz so it's useless for low voltage work as well ... more so.
+Peter Walker Agree, you might be right, the key word is "switchable", however, unless dedicated probes, these switchable 1X probes may not be quite useless; in a low BW (
Thank you Dave for this excellent video! I love all your videos but it is nice to pick things up like this which weren't discussed in the university (unfortunately). It may take some work but I'd hope the appreciation from the community encourages more in the future! Thanks!
I loved this video. I know a fair bit of theory and thought we were going to get into rise time limitations of the R/C compensation. I NEVER knew about the deliberately lossy transmission line. Dave, please do more theory vids.
I've been using scopes for twenty years and never knew this. I was taught to always use 10x because of the higher bandwidth, and noticed it on the datasheet, but never needed to take the time to figure out WHY.
They're great for me, because I'm just doing audio (20-20k Hz) right now using an old analog 30MHz scope. I do want to do radio at some point though, so a 1GHz scope and probes would be nice to have when I start with it.
Very grateful for this video seeing as I'm currently playing with building an 80MHz RF front-end and was wondering how best to model probes for LTSpice to understand what voltages the ADC will be seeing. Nice one Dave!
Brilliant explanation Dave. It would be great to continue this by explaining differential probes, how they work and possibly design one to build. Low frequency of course.
Sometimes the route is much more enjoyable than the destination!!!! I'll not take for granted the X10 scale and will think thrice before I use the X1!!! Thanks so much!
Thank you for answering this. Had trouble finding this anywhere else. Didn't realize a coax had so much capacitance. This threw me off on a high impedance measurement when trying to use 1x mode, now I know why.
Dave, this was great. You do tons of entertaining things, and you do them really well. Your educational stuff is absolute gold. Keep it up.
11 років тому
This is very usefull information, THX a lot. The resistant core of the coax also helps to block from signal ringing and mirroring at the input of the scope.
Dave, One missing element in your trasmission line analysis is INDUCTANCE. Impedance (Z) is equal to the square root of the ratio of L /C. The whole problem of BW in your case is related to matching (optimal transfer of power) the input and output Z's to the trasmission line. The 9 Mohms helps expanding the BW but introduces resistive losses, hence the X10. A 50 ohms coax will not help without proper matching or termination. I think it is time to review transmission line theory. Cheers!
No, it's all to do with transmission line matching and compensation. The probe is transmission line optimised for x10 mode, so is all mis-matched when you switch to x1.
100x is also useful for low voltage sensitive ccts, e.g. 32K xtal oscillators and micropower /low leakage stuff. For low voltage, low frequency use, a 90M resistor in series with the top of a 10x probe is a cheap option.
@24:06, why we didn't take account 100pF cable parasitic capacitance for the total input capacitance, it should be (parallel of 100pF+15pF)? Assume even the resistive conductor also has some stray capacitance?
I would say that everything is little simpler, since i had to design my own cable for oscilloscope probe. Most important feature of lossy cable is to have very low capacitance, so wire must be as thin as possible. If you try to replace it with regular coax you still can compensate everything for any bandwidth but input impedance will be terrible, what makes measurements impossible( done that and was puzzled why everything stops working when i attach my probe) probe impedance is basically cable impedance divided by multiplier. lossy cable allows you to achieve higher input impedance resistance does not seem to play significant role however it ensures that there will be no reflection because of improper termination and also it may improve impedance by turning cable itself into atenuator
Interesting to see how the pure truth not earns many thumbs ups. I add some other (probably even less popular) fact: the other reason of the high wire resistance is the material choice. The wire must be strong and flexible despite of the very small diameter, and also not soluble in tin during soldering, this is why it cannot be made from copper, but other materials with higher specific resistivity must be used.
Another reason why x1 probes are designed that way (internal lossy transmission line) is protection of the sensitive input circuitry of the oscilloscope. A direct coax cable surely has the best bandwidth, but it will also allow anything to pass, including signal under test as well as any static HV peaks which might easily damage the ESD devices inside the scope. The design of ultra-high bandwidth/high gain voltage amplifiers combined with effective protection circuitry is a form of art in the electronics world.
Back for a "2nd suck of the sav". Good stuff! Ok, I'm a slow learner. Re: wiggle wiggle center conductor. I was told back in the day (elect shop) that the wiggle was to help [center] the conductor in the dialectic more consistently. On some coax's they will include a plastic/teflon? spiral to do the same thing. That being said I like the "flexibility reason" too. Could easily be both 😁 Thanks again for the gray matter re-charge. Cheers. 🇺🇸
Electricians tape tends to fix that problem: set it, tape it, forget it. Also that strip of red tape is an easy way to know which one of the probes in the box is set to 1X
Thank you Dave for pointing that out. It is useful to know the X1 is so low BW and that a coax is actually better in low volt and hi BW applications. Non intuitive. I love your blogs ( I love your accent, LOL). BTW, how do you pick coax for that condition. 50ohm, 75ohm, etc.
They have a special coax just for data transfer on satellites. Not sure of the resistance? but it has double braided Shield 100% copper with 100% copper wire in Center. It's about less than half the diameter of a TV cable wire.
Hi Dave you never said anything about the 50 ohm resistor of the signal gen. That should be included in your calcs in order to be more precise on the -3dB point. I have seen a lot of your videos. As always they were extremely helpful. Thanks again.
I was right there with you until about the 24 minute mark. The scope probe as you mentioned is a distributed, lossy transmission line. You measured it to be around 330 ohms at DC / low frequency. It will be different at higher frequencies and as you mentioned is optimized for 10x mode and to achieve high bandwidth. The characteristics of the transmission line, however, are determined by geometry and materials and are the same whether you are on 1x mode or 10x mode. The transmission line doesn't look any different at 20 MHz (just picked a number) in 1x mode than it does at 20 MHz in 10x mode. Which means the effect of its interaction with the 15pF scope input capacitance would be the same at 1x mode or 10x mode. Also, what you are changing between 1x and 10x mode is whether the 9Meg resistor and ~15pF tip capacitance are in circuit or bypassed. So wouldn't the bandwidth limitation in 1x mode have to do with the interaction between the lossy line's RLC and whether or not the 15pF tip capacitance is in-circuit or shorted, and not the interaction between the lossy line and the scope's input capacitance? If not, what am I missing? Great video in either case. Thanks for posting.
23:30 so the equivalent circuit is a low pass filter R=330R C=15pf. Did Dave forget to add the coax capacitance? 330R 80pf sounds more like it to give the correct 3db bandwidth. Otherwise it sounds too high, about 30Mhz.
The x10 probe reduces the signal amplitude by ten times. This forces the scope to amplify the input signal by ten to get back to the original scaling (which means it will also amplify any input noise by ten as well). So the x1 probe is more sensitive and can capture low level signals with better resolution and less noise.
What kind of a reistor is that 9MOhm in the tip of the probe. I am guessing if I put just a common thin film resistor from aliexpress, the inductance would mess up the measurements. (I blew up a 10x probe and I am looking to fix it for fun and learning, but I can't really find spare parts for it)
If your signal contains frequency components higher than the probe's bandwidth (in x1 mode), the signal will APPEAR attenuated and 'rounded off' (on the DSO) but the signal itself is unaffected right? It's just a case where your probe isn't good enough to 'resolve' the higher frequencies (e.g., in the case of a square wave, the higher-frequency components are what makes the corners sharp).
it's a phychological, measurable effect. It depends if you are natively a right-to-left or left-to-right script reader. eg: English readers seem to prefer lecturer on left, info on right, Arabic readers seem to prefer the opposite. It doesn't make much difference to most people, but I was told years ago to present pre-drawn boards from the left if I don't want to "get in the way" (and that doesn't mean physically). Personally I don't notice a difference but swapping sides is distracting to me
Hi, Dave! In case of x1 position, you say about voltage devider model with cabel distributed 330 Ohm and 1 kOhm capacitive resistance. But what about x10 position? If we discuss with voltage devider model, it shoul be 9 megOhm + 330 cable distributed Ohm resistance, so that thing makes signal almost zero amplitude. How it works in x10 position?
Hi Dave, thanks for the info sharing. For me, x1 mode of the passive probe is very useful for probing low level signal. Maybe you can spend some time to the DIY passive probe that I sent to you last year. Have fun... ^_^...
Wow, didn't know that, now I have to go measure R on leads of my brand new Siglent. I just wonder if that resistance wire is Ni-chrome, same resistive stuff they use in electric heaters and blankets - easy way to tell is, try to solder it, Ni-chrome absolutely will not stick to normal solder. (if you ever wreck an electric blanket, salvage the resistance wire, but you have to crimp all connections.)
I am no engineer. But what I picture when you're talking about this is Eddy currents going back and forth. Or electricity, A/C ...It can only travel so fast on such a thin wire with such a great resistance.
Since I am fairly new to electronics I am trying to understand oscilloscopes and probe use. I watched this with keen interest, others concerning 10x probe use and even W2EWs video about the effects of ground lead length on signal quality. Frankly, I still can't quite understand the value of 1x probes, rather than just using a 10x probe for everything. What am I missing? Many thanks.
So the more critical question I had was given the 1x setting appears crap in all of the Parameters then what is the corner use case for ever needing the 1x setting at all , why bother shipping the scopes with 1x as an option and not just fix them to 10x? Is it correct that it only matters with very weak signal levels at the very bottom end of the scopes capability? (Which by definition also have to be low frequency)? So what when scoping the output of a microphone diaphragm?
Hi Dave, You didn't do one thing when you damage this probe already: measure the whole lenght of this inner cable. You will be suprised how long is it!
Thanks for the video! But I can't understand how a passive circuit can have higher amplitude at the output than at the input. I mean the 'funny business' at 27:45, but I get the idea what was meant.
However coax will change impedance at large change of frequency. The "crincle" form choke points in the signal that changes with the frequency. the cables are rated at 50 Homs up to 900 mhz 5
smaller voltages measurements most scope go up to 5mV/div, in x10 thats microvolts. HF x1 probes would be useful for that, a 20mVpp sine wave is at least visible in 4 divisions instead of half (2mVpp) at least that's what come to my mind.
Thank You! You just saved me from trying to fix a local oscillator circuit that wasn't broke due to a low level reading on my scope with 1x probe at 36 mhz. I switched to x10 and there was my correct level! I really enjoy your videos.
Yes, highly recommended. I wanted to cover the x1 mode issue that Doug and everyone else seem to skip in their talks that focus more on x10 probes.
Dave, you've taught me so much about electronics. Thank you. I bet no one at my college will ever cover this!
So many answer to questions I didn't know I wanted to ask until you asked answered them. Very groovy Mr Dave you got my sub for the ride
excellent explanation, spot on. I had this explanation as a baby ship's radio officer in the late 80's in those days our radio and even some radar kit was lower then your average CPU FSB. - times change.
This should really be compulsory stuff for new engineers yet as you say it's rarely mentioned, almost forgotten knowledge - tell us more Mr von Daniken !
Thanks Dave. When I first started work at an electronics repair centre (many, many years ago) my supervisor handed me a brand new scope, then switched both of my probes to x10 before handing them to me.
Yes, it's big subject actually, and you could spend ages investigating how it all works and is optimised for best performance.
You should go into teaching Dave, I've learnt more in this video alone than a whole year in a master's EE course, keep it up!
That was fabulous. These are things we generally never find out the reason why. Cheers Dave.
1X probes are not useless, they are very good for low voltage measurements, in order to keep the signal-to-noise ration as high as possible. Great video, though!
+electrocomm What he said was switchable x10 probes are useless as x1. You effectively have a hidden 470Ω resistor in series with your probe, and as shown your 'low voltage signal' will sink into the mud of noise @ 10MHz so it's useless for low voltage work as well ... more so.
+Peter Walker Agree, you might be right, the key word is "switchable", however, unless dedicated probes, these switchable 1X probes may not be quite useless; in a low BW (
LaurMTB ツ as Dave mentions, for a true 1:1 "probe", just make your own out of a piece of coax cable.
Thank you Dave for this excellent video! I love all your videos but it is nice to pick things up like this which weren't discussed in the university (unfortunately). It may take some work but I'd hope the appreciation from the community encourages more in the future! Thanks!
I loved this video. I know a fair bit of theory and thought we were going to get into rise time limitations of the R/C compensation. I NEVER knew about the deliberately lossy transmission line. Dave, please do more theory vids.
I've been using scopes for twenty years and never knew this. I was taught to always use 10x because of the higher bandwidth, and noticed it on the datasheet, but never needed to take the time to figure out WHY.
They're great for me, because I'm just doing audio (20-20k Hz) right now using an old analog 30MHz scope. I do want to do radio at some point though, so a 1GHz scope and probes would be nice to have when I start with it.
"Now, the first thing you should say is, well, bullshit; show us!"
Thats gold, love it!
Very grateful for this video seeing as I'm currently playing with building an 80MHz RF front-end and was wondering how best to model probes for LTSpice to understand what voltages the ADC will be seeing. Nice one Dave!
Thanks again Dave.... Your video's are much appreciated. I learn so much information each time. Keep them coming... Your a fantastic TEACHER.
Brilliant explanation Dave.
It would be great to continue this by explaining differential probes, how they work and possibly design one to build. Low frequency of course.
Low level signal measurement, e.g. 1mV/DIV. With x10 you trade signal level for more bandwidth, so your scope becomes 10mV or 20mV/DIV minimum
Sometimes the route is much more enjoyable than the destination!!!! I'll not take for granted the X10 scale and will think thrice before I use the X1!!! Thanks so much!
Thank you for answering this. Had trouble finding this anywhere else. Didn't realize a coax had so much capacitance. This threw me off on a high impedance measurement when trying to use 1x mode, now I know why.
Holy crap, I learnt so much! Thanks Dave!
Btw: Could you do more videos like this?
Dave, that was hugely informative, thank you
Blew my mind. I didnt have a clue about that. Never bothered to measure probe resistance. Excellent.
Dave, this was great. You do tons of entertaining things, and you do them really well. Your educational stuff is absolute gold. Keep it up.
This is very usefull information, THX a lot. The resistant core of the coax also helps to block from signal ringing and mirroring at the input of the scope.
Dave, One missing element in your trasmission line analysis is INDUCTANCE. Impedance (Z) is equal to the square root of the ratio of L /C. The whole problem of BW in your case is related to matching (optimal transfer of power) the input and output Z's to the trasmission line. The 9 Mohms helps expanding the BW but introduces resistive losses, hence the X10. A 50 ohms coax will not help without proper matching or termination. I think it is time to review transmission line theory. Cheers!
The impedance of a LOSSY transmission is NOT sqrt(L/C)... but sqrt( (R+jwL) / (G+ jwC ) )
Awesome video! The diagram with the lossy transmission line modeled as a series of RC circuits says it all.
No, it's all to do with transmission line matching and compensation. The probe is transmission line optimised for x10 mode, so is all mis-matched when you switch to x1.
I had so many issues with transmission line theory when i was working on my degree its a very difficult subject
100x is also useful for low voltage sensitive ccts, e.g. 32K xtal oscillators and micropower /low leakage stuff. For low voltage, low frequency use, a 90M resistor in series with the top of a 10x probe is a cheap option.
Great video Dave, I'm glad you explained this. Yes, the big white board on the wall is much nicer.
Thank you! Please Dave continue with this stuff and explanations! Greetings from Bulgaria!
Yes, the 50ohm coax of course needs proper termination to work well, a whole other topic. As is the transmission line matching.
Love the explanation, Dave...
Dave's probing genius rocks! Thank you for the video!
@24:06, why we didn't take account 100pF cable parasitic capacitance for the total input capacitance, it should be (parallel of 100pF+15pF)? Assume even the resistive conductor also has some stray capacitance?
I would say that everything is little simpler, since i had to design my own cable for oscilloscope probe.
Most important feature of lossy cable is to have very low capacitance, so wire must be as thin as possible. If you try to replace it with regular coax you still can compensate everything for any bandwidth but input impedance will be terrible, what makes measurements impossible( done that and was puzzled why everything stops working when i attach my probe)
probe impedance is basically cable impedance divided by multiplier.
lossy cable allows you to achieve higher input impedance
resistance does not seem to play significant role however it ensures that there will be no reflection because of improper termination
and also it may improve impedance by turning cable itself into atenuator
Interesting to see how the pure truth not earns many thumbs ups.
I add some other (probably even less popular) fact: the other reason of the high wire resistance is the material choice. The wire must be strong and flexible despite of the very small diameter, and also not soluble in tin during soldering, this is why it cannot be made from copper, but other materials with higher specific resistivity must be used.
Another reason why x1 probes are designed that way (internal lossy transmission line) is protection of the sensitive input circuitry of the oscilloscope. A direct coax cable surely has the best bandwidth, but it will also allow anything to pass, including signal under test as well as any static HV peaks which might easily damage the ESD devices inside the scope. The design of ultra-high bandwidth/high gain voltage amplifiers combined with effective protection circuitry is a form of art in the electronics world.
And again, I hope I learned something! That was useful and most informative - thanks a lot :)
Back for a "2nd suck of the sav". Good stuff! Ok, I'm a slow learner.
Re: wiggle wiggle center conductor. I was told back in the day (elect shop) that the wiggle was to help [center] the conductor in the dialectic more consistently. On some coax's they will include a plastic/teflon? spiral to do the same thing. That being said I like the "flexibility reason" too. Could easily be both 😁 Thanks again for the gray matter re-charge. Cheers. 🇺🇸
thanks Dave, I had no idea about probes, but you're right about those switches on the probes, they can drive you crazy.
Electricians tape tends to fix that problem: set it, tape it, forget it.
Also that strip of red tape is an easy way to know which one of the probes in the box is set to 1X
Awesome stuff Dave, really enjoyed this one! Whiteboard looks great
Thank you Dave for pointing that out. It is useful to know the X1 is so low BW and that a coax is actually better in low volt and hi BW applications. Non intuitive. I love your blogs ( I love your accent, LOL). BTW, how do you pick coax for that condition. 50ohm, 75ohm, etc.
They have a special coax just for data transfer on satellites. Not sure of the resistance? but it has double braided Shield 100% copper with 100% copper wire in Center. It's about less than half the diameter of a TV cable wire.
very useful video.
A series on sources/corrections for measurement errors would be a good video/series.
Eric Wasatonic did a fascination series on building his own x100 probe as well.
Look at this series starting 25 Feb 2013
Hi Dave you never said anything about the 50 ohm resistor of the signal gen. That should be included in your calcs in order to be more precise on the -3dB point. I have seen a lot of your videos. As always they were extremely helpful. Thanks again.
Good stuff, well explained and showed. Keep them up Dave!
Brilliant info...so what is the advantage of having ORIGINAL probes , say for a Tektronic 465M if it did not come with original probes?
Cheers
Thank you Dave. I learned something I didn't know.👍😊
Very interesting! Nobody in my company (one of the aorld leaders for telecom base station power supplys) could explain me this "phenomen".
I was right there with you until about the 24 minute mark. The scope probe as you mentioned is a distributed, lossy transmission line. You measured it to be around 330 ohms at DC / low frequency. It will be different at higher frequencies and as you mentioned is optimized for 10x mode and to achieve high bandwidth. The characteristics of the transmission line, however, are determined by geometry and materials and are the same whether you are on 1x mode or 10x mode. The transmission line doesn't look any different at 20 MHz (just picked a number) in 1x mode than it does at 20 MHz in 10x mode. Which means the effect of its interaction with the 15pF scope input capacitance would be the same at 1x mode or 10x mode.
Also, what you are changing between 1x and 10x mode is whether the 9Meg resistor and ~15pF tip capacitance are in circuit or bypassed. So wouldn't the bandwidth limitation in 1x mode have to do with the interaction between the lossy line's RLC and whether or not the 15pF tip capacitance is in-circuit or shorted, and not the interaction between the lossy line and the scope's input capacitance? If not, what am I missing?
Great video in either case. Thanks for posting.
23:30 so the equivalent circuit is a low pass filter R=330R C=15pf. Did Dave forget to add the coax capacitance? 330R 80pf sounds more like it to give the correct 3db bandwidth. Otherwise it sounds too high, about 30Mhz.
The x10 probe reduces the signal amplitude by ten times. This forces the scope to amplify the input signal by ten to get back to the original scaling (which means it will also amplify any input noise by ten as well). So the x1 probe is more sensitive and can capture low level signals with better resolution and less noise.
Whenever I simulate things like this I am wondering if group delay should worry us too...
Good subject to investigate and a Great presentation! Thank You!
Do people prefer that one to the old hand held one? I think it works much better.
No, you can roll your own. I've done a video with Doug on high voltage probe design.
Good to mention this, anyone who works in electronics has to know this, otherwise they should never have been hired.
What kind of a reistor is that 9MOhm in the tip of the probe. I am guessing if I put just a common thin film resistor from aliexpress, the inductance would mess up the measurements.
(I blew up a 10x probe and I am looking to fix it for fun and learning, but I can't really find spare parts for it)
Now I am 10x more optimized to watch another EEVblog!
10x means divided by 10
Excellent video Dave!
If your signal contains frequency components higher than the probe's bandwidth (in x1 mode), the signal will APPEAR attenuated and 'rounded off' (on the DSO) but the signal itself is unaffected right? It's just a case where your probe isn't good enough to 'resolve' the higher frequencies (e.g., in the case of a square wave, the higher-frequency components are what makes the corners sharp).
Your videos is a brilliant youtube mine. 👍🏼
it's a phychological, measurable effect. It depends if you are natively a right-to-left or left-to-right script reader. eg: English readers seem to prefer lecturer on left, info on right, Arabic readers seem to prefer the opposite. It doesn't make much difference to most people, but I was told years ago to present pre-drawn boards from the left if I don't want to "get in the way" (and that doesn't mean physically). Personally I don't notice a difference but
swapping sides is distracting to me
Hi, Dave! In case of x1 position, you say about voltage devider model with cabel distributed 330 Ohm and 1 kOhm capacitive resistance. But what about x10 position? If we discuss with voltage devider model, it shoul be 9 megOhm + 330 cable distributed Ohm resistance, so that thing makes signal almost zero amplitude. How it works in x10 position?
@25:18" It doesn't matter a rats ass" ... gold aussie Tech talk hehe love it
Excellent! As always! Thank you!
Great tutorial thanks we learn somethings every day.!!
😊 Again.
Where that 1k resistance parallel to the oscilloscope input comes from?
No, usually not. Yes, the odd shuffle was required in this one.
At the beginning transmission by cable seems easier than transmission by radio. But at the end it is the other way round.
Learnt EMT + Control system + Network Theory in one video, Thanks
Learned a lot. Thanks.
yeah agreed, newone is very pro but please use the old one for special quick spur-of-the-minute squiggles now and again for some nostalgia :)
I like this DaveCAD-HD! It looks great.
Hi Dave, thanks for the info sharing. For me, x1 mode of the passive probe is very useful for probing low level signal. Maybe you can spend some time to the DIY passive probe that I sent to you last year. Have fun... ^_^...
Wow, didn't know that, now I have to go measure R on leads of my brand new Siglent.
I just wonder if that resistance wire is Ni-chrome, same resistive stuff they use in electric heaters and blankets - easy way to tell is, try to solder it, Ni-chrome absolutely will not stick to normal solder. (if you ever wreck an electric blanket, salvage the resistance wire, but you have to crimp all connections.)
I am no engineer. But what I picture when you're talking about this is Eddy currents going back and forth. Or electricity, A/C ...It can only travel so fast on such a thin wire with such a great resistance.
Another great video mate
You are a true god of electronics!
Did you what, watched like 2 of them? They are all great!
So, is it best to get dedicated separate high frequency 1x and 10x high frequency probes if you need to test high frequencies?
Since I am fairly new to electronics I am trying to understand oscilloscopes and probe use. I watched this with keen interest, others concerning 10x probe use and even W2EWs video about the effects of ground lead length on signal quality. Frankly, I still can't quite understand the value of 1x probes, rather than just using a 10x probe for everything. What am I missing? Many thanks.
So the more critical question I had was given the 1x setting appears crap in all of the Parameters then what is the corner use case for ever needing the 1x setting at all , why bother shipping the scopes with 1x as an option and not just fix them to 10x?
Is it correct that it only matters with very weak signal levels at the very bottom end of the scopes capability? (Which by definition also have to be low frequency)?
So what when scoping the output of a microphone diaphragm?
Hey Dave, at 23:10 the video jumps from having a 15 pF tip cap to a 1k Ohm resistor. What is that about? What am I missing?
Hi sir, When you fill in the formule of Xc = 1/2pifC = 1/ 2pi10MHz15pF you get 1k ohm. So you can replace them for the equivalent reactance.
@@TheMrTxM Thanks for your reply :-)
Very useful video!
Hi Dave,
You didn't do one thing when you damage this probe already: measure the whole lenght of this inner cable. You will be suprised how long is it!
Great vid thanks.
What do you think about the iPad app oscilloscopes that are available for those who don't have the $ to buy a proper one?
Thanks for the video!
But I can't understand how a passive circuit can have higher amplitude at the output than at the input. I mean the 'funny business' at 27:45, but I get the idea what was meant.
Reflected capacitance? Please explain!
Waling off at the end like a professional you tuber. How stylish.
And this is why scope probes must be handled carefully. Center conductor is so thin.
I have an old analog 20Mhz scope and I measured the BW of the probes to be 500kHz on x1
However coax will change impedance at large change of frequency. The "crincle" form choke points in the signal that changes with the frequency.
the cables are rated at 50 Homs up to 900 mhz 5
Man, I love these videos
Hi Dave, can you make some quick video on measurement of smd capacitors and coils?
What does those capacitance do?
smaller voltages measurements
most scope go up to 5mV/div, in x10 thats microvolts.
HF x1 probes would be useful for that, a 20mVpp sine wave is at least visible in 4 divisions instead of half (2mVpp)
at least that's what come to my mind.
Didn't think about that, yeah, I've swapped sides!