How to Measure Current with an Oscilloscope - Take the Mystery Out of Oscilloscope Probing
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- Опубліковано 19 лис 2017
- You'll be surprised how easy it is to measure current with a scope!
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How to measure current with an oscilloscope? You can use the Ohm's law method and calculate current with a measured voltage. Or, you can use a current probe. Join Ally as she unveils this oscilloscope probing mystery.
Ally will walk through 3 situations where you'd want to use a current probe, and which type of current probe works best for each.
#1 High current- Rogowski coil probe
#2 10ma-30A- Clamp-on current probe
#3 Low current- high sensitivity probe
You can ask us questions on Facebook
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Learn more about using oscilloscopes:
oscilloscopelearningcenter.com
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Oscilloscope probing is arguably the most misunderstood but critically important aspects of making a good measurement. Take the Mystery Out of Probing video series, hosted by Ally Dartt, will unveil some of the greatest probing mysteries to help you make the most of your oscilloscope probes and improve your measurement accuracy.
#oscilloscope #probing #probe #oscilloscopeprobe #currentprobe #ohmslaw #oscilloscopes #howto #engineering #rogowskicoil #clamponcurrentprobe #clampon #highsensitivitycurrentprobe - Наука та технологія
Check out the probing pitfalls training kit here:
► bit.ly/ProbingPitfalls ◄
Can i get one of it for free
Step 1 of using a current probe with an oscilloscope:
Rob a bank
True.
lmao best fucking comment
ElectroBOOM is having a ball with those scopes
I bought a new scope thanks/because of him. The love he sends towards keysight is very real. They have awesome classes available to everyone as well. When he said they were giving scopes to schools, I bought one.
I'll stuck with a 1 ohm resistor thanks. I don't want to have to take out a loan to measure current over time
Stock stuck with a 1 ohm resistor
yo that thing must be an absolute unit to handle high power when hooked up to 12V
You can get some good multimeters on Amazon for $10-$20.
@@bruhmomenthdr7575 lol
I am electrical engineer and it is one of the best and to the point electrical-knowledge that is shared on UA-cam.
Thank you!
Great video. Spotlessly presented. I just wish I had the money to buy those probes.
THANK YOU!! This has been very helpful!
It was very helpful to know that there are different strategies depending upon how much current I’m working with.
Did I just watch an advertisement for a current probe for an oscilloscope?
Fried Mule tru
Michi Lo wait there was an oscilloscope in this video? sorry completely missed...
did you like her?
what was hotter? current probe or metal core?
Actually, we did by robot lady
Excellent insight, great presentation. Good job, thank you.
Ally, it was so refreshing to watch your video, you are an incredible speaker and so smart! Thanks for making a typically boring subject way better!!
She’s incredibly easy on the eyes. I never understood men in early engineering. Smart women are so desirable. Arguments tend not to be argument but rather discussions with higher understanding in mind. Idiots just want to be right to protect they pride or agenda. It’s a real shame how boring electronics, math, chemistry, biology and all that is sooo incredibly boring to kids these days so how do you raise a smart daughter? Or son? Girls are bored and boys know everything so need to learn nothing. The fuk?! I grew up with not much. Old junk was my go to. Nothing fills the void except knowledge and even that is fragile and can shatter. What am I on about.
I'm in love - with that Oscilloscope, of course.
Only costs 75000$
Wasn't a particularly good day until I saw that you guys had published a new video.
Informative, charming and educational, as usual (and as we've come to expect from this channel). You are consistently spoiling us all with great content!
If so what are your thoughts ?.
Great job, Ally! Very well presented!
This is not current. It was uploaded in 2017 :) lol
Still holds up!
@keysight labs u didnt get the joke !
@@b-bnt yeah 😂 the bot known as Keysight failed to get the joke.
The N2820A/21A dual range probe is really cool!
Good explanation, thanks!
Excellent video! Exactly the info I needed. Keep up the good work. Surely wish UA-cam was a thing when I went through university.
Thanks for this!
Thank you Ally!
short, simple, conscience good video. Careful probing ~10A high currents using a sensitive mA~1A probe , they melt. :)
Great video - I might add that I have had to calculate power into a load at high voltages and high Z (transmitter modulators) at audio frequencies and no way to measure voltage directly with a simple meter. Knowing the load Z, I measure the current with a Tektronix current probe and a vintage scope, with the probe clamped around high voltage meter-lead wire, convert the PP voltage to RMS and do the math. Works great and keeps us away from direct contact with the HV.
Derived from the derivative of the polynomial function. What a concept!
Thank you.
Well-spoken, articulate delivery. Excellent. I'm buying a probe!
Did you really buy. Its been years and i still cant afford a probe. I can afford a 1 ohm resistor.
me to, aqll this talk about probing
came for the creepy comments from engineering students but left disappointed.
We try to keep the comments section focused on the equipment and the topics!
Do you have the best viewer base on youtube, or are you doing 100/100 job on comment administration?
Interesting anyway, just got a bit surprised by the prices. Have to discuss with my SO before shopping :hmm:
Check out JoFos comment, you won't be disappointed lol
At least you leaved one xD
@@RicondaRacing They got it xDD (not there as of 2/26/20)xDD
My 40 year old tektronix current probe works great and has less noise than the ones you showed here. Of course it only has a 50 MHz bandwidth, and these are 150MHz so the noise should be about 3 times higher, but it looks higher than that.
Excellent
Hell yeah, linear permeability is the best, no worries of the core oversaturation!
How about averaging to mitigate noise? I’ve found my rigol probe to be significantly more accurate with averaging on with constant loads.
Thumbs up good information
Sitting in my old rocking chair, waiting for Xmas and meditating on better days ahead, I thought I heard Ali mention a rogoswki coil. What a wonderful addition to the Xmas 🌲and all wrapped in tinsel. At the moment, I am writing to 🎅 and along with a top spec oscilloscope, I am now tempted to include some fancy current probes. We are promised snow this week in Galway, so it's time to be on the lookout for a well fed turkey. Slàn libh go fòil agus beannacht Dè do gach èinne.
lol.....
you need to do some probing , , ,
I don't even know how to use Oscilloscope, but still enjoy most of your video...
For repairs and trouble shooting measuring current is often more informative as measuring voltage. But almost no-one makes probes for that. II use diff-probes for measuring current through a part but contactless is the niced way.
HP used to make a very nice current probe for this, the 547A. It was non contact. I have several current probes (sorry, they are from the competition). Besides some clamp probes and the 547A, I have a modern contacless probe (it uses a fluxgate)
when did HP stop making those?
This is awesome!
Thanks!
I like her. Great Charisma.
Great tutorial!
I'm trying to plot AC current for a household AC wall panel over time to quantify how the current draw varies through the day. My Pico scope is using an AC/DC current probe, and I understandably get a 60 Hz sine wave centered on zero. I think what I need is an RMS integral, but I'm not sure how to do that to get a running value of effective current with the scope. I think I can get peak to peak voltage, and from that can assume a pure sine wave and divide by (2sqrt2) on a math channel. Is there a more accurate way to compute the integral and display results, more like a true rms graphing multimeter?
spelunkerd having time off from cars? Try math channel sqrt(integral(A*A)/T) + freq(A) - freq(A), copyright someone on pico forum. It’s normal that you get 60Hz centered on zero.
@keysight - what do you suggest to measure ripples in 50A to 100A DC current from AC to DC power supply ??
Holy crap! This is the first time seeing this channel and it’s great! Ally, what is your background? BSEE? You’re so young, but present this stuff better than most 40-something-year-olds! My point is, you have a gift, and I’m glad you’re using it so well, especially to educate others. Be well. 👍
Thanks! Ally has a computer engineering background
@@KeysightLabs same here, I knew I saw brilliance! 😂
منتج جداً رائع لقياس التيارات الكبيرة
Another great Keysight scope video, well presented, Thanks!
The N7026A must be new current probe, I had not seen it before.
What was the older one in comparison, the 1147B?
What a difference!
I wish you would make a new awesome video like this one, every day of the week !
Hi Elden, it's actually more of an upgrade from the N2893A, but it could also be used in place of an 1147B for better performance. We'll keep the videos coming!
I looked that the N7026A datasheet and noticed that it requires an external power supply.
One of the benefits of the Keysight probes has always been that no external power supply was needed.
Why is the N7026A not powered over the auto probe interface like on the N2893A and the 1147B?
And ... how did you get away with not using the external power supply in your video at 2:50?
The external power supply is basically a range-booster if you need to make higher Amp measurement. You can do +-15A from the AutoProbe, and +-30A with the external supply.
Super cool
Will these devices capture the current in a single sinusoidal waveform of a few milliseconds duration?
Can i haz that scope Keysight?
I'm in loved with the Oscilloscope
My (Agilent) oscilloscope can multiply channels by each other but not by a constant. If it could, I could apply the scaling required for a measurement resistor instead of doing it in my head.
😍... both the ac/dc probes and Aly
"There are 3 situations where you need to measure current:
If you are working with very high currents
Very low currents
Or something inbetween"
Couldn't you just say 'current'?
lmao
She classified it like that to show later the different strategies for each current range.
It's like picking a thermometer to measure temperature. Say all you've got is a mercury thermometer. That's fine, unless the thing you're measuring is so cold that the mercury freezes. Or if it's so hot that the mercury boils or the glass melts.
Im wondering why scope is grounded to earth? Is that for safety reasons/signal reference or something like this? As i see it causes some problems, so why we use it?
How would you measure current across a 'series' component using a scope? The series component is a resistor and is connected in-between power supply and amplifier vcc pin.
If it's a resistor, you can use a differential probe to measure the voltage drop across the resistor. Check out this video for more: ua-cam.com/video/OZDijMDHmtI/v-deo.html
good vibrations
Thx you did a great job but failed to mention the number one obstacle of using a current probe. Cost. I have a small consulting company and i have never been able to justify the cost of a decent probe. I have a cheap probe and when that does not suffice a shunt most often can work. With this method most modern scopes can do math in the math function so you display an actual current measure.
Is any adjustments in button we should in the oscope for current? 🤔
Generally, the scope will recognize a current probe and you won't have to change anything. You can manually set up a channel with the right attenuation ratio and current/voltage selection if you need, though.
I hate to be pedantic, but if you’re using a resistor inserted into the circuit to measure the current using voltage drop and Ohm's law, wouldn’t it be a _series_ resistor (in line, with all the current flowing through it) rather than a shunt resistor, which would be in parallel with something else, and thus not see all the current?
Wow ....
Wow
Only cost another mortgage..
@Blondie SL Much like drugs
Nanosecond range: With an ideal resistor, V = R I, fine, but if the voltage increases instantaneously from V0 to V1, the current cannot raises in an instant from I0 to I1: the number of moving electrons is the same (the number of atoms don't change) so it is their speed which should increase and since electrons have mass, it takes some time to raise from I0 to I1. So, basically, since V0 is instantaneously risen to V1, *at that moment*, we have V=V1, still I = I0, such that V = V1 > R I . The time it takes for the current to raise from I0 to I1 can be in the pico to the nano second range. So the resistor technique is not fully trustable for these time ranges, no?
is it?
@@user-ww2lc1yo9c In fact, the electrical field moves faster (about one third of c in a copper wire) and the electrons start moving due to the increase in the field, rather than other electrons pushing/crashing onto them. But there is still a delay before getting a steady flow, a delay which is negligeable in everyday calculations done on a typical circuit.
I’m an idiot not an engineer, but I’d like the ability to measure the charge/discharge details (voltage and current of a 12V lead acid battery. I’ve got a clamp meter that goes up to 2,000DCA to measure the starting current but that’s one point in time, I’m more interested in the current output of the charging system which can be between 2-10 (up to 50A). Halp.
In the thumbnail she looked exactly like Jenna Fischer (Pam from The Office). I clicked because of that.
She also forgot to mention that coils work differently with AC and DC, AC you have inductive reactance, in DC it access a dead short.
You're right. As the frequency goes up in the probe’s input signal, the inductive reactance goes up as well. And as the frequency approaches zero or DC, the inductive reactance would decrease to zero, acting like a short circuit.
For our clamp-on type current probe (including the new N7026A), we use a hall effect sensor that covers accurate DC measurement in place of using the AC transformer. This is a very effective way of measuring DC and AC with a single current probe.
If I measured current yesterday is that still current?
😂
some of this would help the automotive diagnostics
Yes. You can spot prefailure conditions in commutated DC motors before they completely fail. Fuel pumps, blowers and fans....
So how do I build one of these Rogowski probes? Oh... you want me to pay hundreds (thousands?) of dollars for one... :/ Come on man, I'm just a normal person trying to get by and experiment. I can't even afford your cheapest replacement screw.
Gahahahhaha so accurate. Droid, it's a "preium" product, they charge enough money that they can comfortably sit down and produce quality in excess quantities.
Someone has to make stuff to the spec that can develop new technology. Also, those prices are the reason they can produce high quality content like this. On the other hand, I agree, could Agilent produce a 30minute video on Rogowski probes and Hall effect DC current probing before your competition poaches this presenter?
☣droid☣ If you need to measure high currents with your scope you can simply use a homemade current transformer and a shunt. Use two high permebility ferrite toroids and wind 32 turns on each of them and loop the wire from the first one through the second one. Now you have a 1:32:32=1:1024 current transformer. You just need to stick your conductor through the toroid and you are done. For example, if you measure 1000A and you use a 10 Ohm shunt you get 1000:1024×10=9,76V on the output. I have successfully measured currents up to 1200A at 80kHz with this method. I use it to monitor the primary current of my DRSSTC.
Experimente 99 i don’t need to buy an expensive clamp meter????
@@experimente9912 i started reading your comment and i was like that's the CT from a DRSSTC... Oh wait it is
Tesla Girl do you play with resonance in the circuits?
looking to some probing , , ,
I noticed that video, thumbnail said "current probes".
Well, obviously. Why would anyone want to show obsolete probes?
It took me longer than I'd like to admit to get this comment
Can we directly connected to mains voltage
Tell superman I said hey!
Guy Harrison LMAO
Thanks for the expanation.! I'm a electrical engineer known about current trafo but didn't know about Rogowski coil and also didn't understand hou a current clamp could messurer a DC current. So i learned something from it.
And sorry for the lot of shit commenters, just ignore them.
Thank goodness for Ohm's law or a clamp meter, it's cheaper.
The Borg would disagree with you on that one!
😁 They always keep saying that Ω is futile, although I do believe it is more about impedance in their case.
🤗okay, I'd better let myself out now. I still haven't found that last crate of self sealing stem bolts yet.. #DefNotAnerd 🖖🏼
Keysight is one of my favorite company in that domain. Could I be the part of you in India 😊
You can always check jobs.keysight.com and see what's open!
@@KeysightLabs Thanks promptness just like ur instruments
Essential point: 0:43
People talk about Android vs Apple all the time, meanwhile I'm just a Keysight fanboy.
Hi Alie!
Wish I could get an oscilloscope
i like Alie
The moment i opened video my kidneys started to hurt
Here i am trying to buy my first oscilloscope.i found out i need an current probe, İ will sell my house now for sure
It's not worth selling the house for! Start with a shunt resistor :)
@@KeysightLabs just joking a bit. Thanks for the video really informative ❤️
Glad it was helpful!
❤️
I thought you were Pam Beesley
I just can't focus on anything else but.....
Brazzers is still better suited until this engineer crosses 30
a nice £20,000 scope is it value
Too bad there aren't any actual low current probes. I mean a uA is pretty modest, but that's just getting your feet wet when it comes to REAL low currents.
Is your 1st name "Back" ? Alley you should be "Q" in an 007 Bond movie...:) make a car inside of an ink pen...
She forgot to mention that oscilloscopes will give you the peak voltage to calculate the current you need the RMS value
That's definitely true- you can measure peak value, RMS value, and many other parameters with an oscilloscope.
Time to shelf your old Heathkit cope and move into the digital age.
need less than 50 micro amps
hb
Note to Keysight - Get Woke, Go Broke!
It's 3am and what even is an oscilloscope exactly???
Go to bed Michael
@@KeysightLabs lmao
Okay, where is my credit card
i listen to metalcore
DIOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOSSSSSSSSS
ok no need to yell Arcelia
@@KeysightLabs sorry, i don't do it again, very Good videos.
Anyone here have small current, high sensitivity probes that aren't $6k?!
did she say 1000 of Amps ??????
It's a thing! Check out wide bandgap semiconductors:
ua-cam.com/video/CGEDVYK8lTQ/v-deo.html
We have at work a 21kA rectifier
Are those glasses for real? or just trying to get Nerd credit?:)
Haha, they're real.
@@KeysightLabs I'm glad to hear it:) I've seen people just wearing frames without lenses. I like that hair:)
Allie can measure my current.
Also, this is a straight up advertisement. "All that math in your head" is overstating it a bit. Resistors are very cheap. That said, there are some cheap Chinese oscilloscope clamps now for $50-100.
I didn't see an oscilloscope.😍
what a cutie!