What is Probe Loading? Take the Mystery Out of Probing

[@fieldsofomagh]

My passive probe is being sent to the Smithsonian museum as a retro tool of a bygone age. God be with the days of the valve radio and the wind up telephone where you could call the operator for the required number and at the same time, discuss the weather forecast for the day ahead. Times have changed and nowadays it's the active probes. We were all quite happy living in our analogue world when one morning, the digital revolution had begun. Never been the same since. Thanks Ally for a great presentation and in the meantime, back to me ole rocking chair.

[@battlecoder]

Well thank you. I'd like to inform you that you've successfully ruined my relationship with my scope. Things just won't be the same. I can no longer trust what it shows me anymore. Jokes aside, this was another quite interesting and well presented video. I'm really glad I subscribed to this channel.

[@tejeshwvardhan1165]

Now i dont know how my gate signal really looks like.

[@d3c0deFPV]

Admittedly, I subscribed here in an attempt to get a free oscilloscope a while back, but I just watched this entire video. Very informative and well presented!

[@tejeshwvardhan1165]

I cant afford oscilloscope , so i m watching the video for the same reason as you are.

[@dollarbutt]

Marketing 101

[@hidayathmydin4676]

Many thanks to Keysight tech team for your dedication and sharing us excellent technical info.👍😀

[@HamzaIshtiaq-ey4cg]

can we use passive probe with 10x settings to reduce loading effects ?

[@KeysightLabs]

Yes, but often the 10:1 probes are used for lower speed signals in 50 ohm mode

[@behysun]

probe training kit link is broken!

[@MuhammadAbubakar-ys2nu]

Pakistan is not listed in any of the regions on Probe training Kit Download link. No book for us? :(

[@turbo2ltr]

Geez, active probes are 4 times what I spent on the whole scope!

[@KeysightLabs]

+turbo2ltr They are definitely more expensive than passive probes, but if you need them they're worth every penny!

[@aniketverma8774]

Higher impedance, means lower loading right?

[@KeysightLabs]

Yeah, the oversimplified way to think about it is like a resistor divider. If the measurement system has a high impedance it pulls less energy from the system it's measuring.

[@gregfaris6959]

Yeah, but "impedance" is a word lawyers would love to have in their domain, because it hides three things. Resistance, and Reactance, the latter covering Capacitance and Inductance, Each of these will be dominant in different geometries and different frequencies. Active probes have active circuitry right up at the probe tip, allowing you to reduce resistance and capacitance to strict minimums, but you may still have substantial inductance from the length of the ground clip, unless you utilise one of the many geometries proposed to also get your ground down to something very close to your measurement point. The good news (for oscilloscope manufacturers) or the bad news (for you) is that as the frequencies of almost everything continue to get ever higher, more elaborate probing and measurement methods are going to have to come into play to get a meaningful measurement of your signals.

[@AlexandreKandalintsev]

Before throwing away your passive probes, try removing that long ground lead ;)

[@rogeronslow1498]

And ensure probe is set to 10x and calibrated.

[@aneeshprasobhan]

Could you guys please explain how long grounded leads and 10x affects the readings ? Thanks.

[@AlexandreKandalintsev]

@@aneeshprasobhanit has series inductance and screws measurements at high frequencies. watch this video (for example) kzbin.info/www/bejne/b4epc5d-jct1qJo

[@AlexandreKandalintsev]

@@aneeshprasobhan and 10x mode has much less input capacitance, see for example kzbin.info/www/bejne/iYmXeXqEjKeYa68

[@aneeshprasobhan]

@@AlexandreKandalintsev Thank you.

[@eldenchang]

Nice video and well presented !

[@johncortex7582]

Let's say I'm using a dedicated power source (eg. unplugged UPS or a battery pack) to power the scope. Can I then measure differential voltage on Mains without blowing up the half of the planet?

[@KeysightLabs]

Officially no, but you can look up how to "float" an oscilloscope and there are some options & considerations

[@gregfaris6959]

Some oscilloscopes are designed to be floated. Such is the case with my now ancient TEK 222PS, which is certified to float up to 850V p-p. These scopes will often be poor in bandwidth and performance compared with everything else on the market, but the application you describe does not require high performance. These scopes will be extremely well isolated, and feature NO metal parts on the outside of the case. Any scope that has anything metal on the outside is required to be tied to mains safety ground, even when running on battery. Whether you comply with that requirement is a personal choice.

[@vaseemmehrancp9372]

Very informative

[@RobeenaShepherd]

Now I'm paranoid nothing I see is real! The probe training kit sounds interesting, but I'm not sure exactly what it is?

[@Psi105]

Usually it's very obvious when an actor is used for doing technical videos, however with this one i can't tell. I really hope she's an engineer. We need more female engineers.

[@KeysightLabs]

+Ben Wilson Ally is an engineer, we don't use actors on our channel.

[@ijheller]

Why would Keysight use actors if they already have engineers on staff?

[@H-77]

@@KeysightLabs Following the HP heritage...

[@disgruntled181]

How can I ask you questions if I don't have a Facebook account and never plan on getting one?

[@KeysightLabs]

Well, you know, you did just ask us a question :)

[@disgruntled181]

Yeah but this a new video so of course you will be looking at it. I'm talking about if I have a question sometime in the future. You say in the description that we can ask questions directly through Facebook. I was asking for another option besides adding it as a comment.

[@KeysightLabs]

Fair enough! We do make sure to track comments on old videos, too, KZbin sends us notifications. You can also ask questions on Twitter or via e-mail at [e-mail].

[@disgruntled181]

Thank you! And keep up the great content!

[@AutomticHeart]

You run into POTENTIAL challenges...Signals don´t match...Aprobepriately low capacitance. I like the nerd puns in there!

[@Buciasda33]

Heh... Shit just got expensive :))))

[@kc2sho]

Probe training kit is a dead link

[@brasildocara]

what is your instagram?