EEVblog #1367 - 5 Types of Oscilloscope Passive Probes COMPARED

Dave looks at the pros and cons of 5 different types of oscilloscope passive probes.
Switchable x1/x10, Fixed x10, High voltage single ended, DIY Transmission line Z0 probe, and BNC to banana/croc leads.
PART 1 of 2

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[matthwc]

So many times I accidentally left my probes in 1x, and my scope is set to 10x or the other way around. And I sit there looking at my circuit thinking something is really wrong then I realize it's just

[Afrotechmods]

Great video and I love your probe collection. I have found that X1 attenuation instead of X10 can also be useful in high EMI environments because the lower impedance makes them less susceptible to stray fields. Look forward to seeing part 2 of this series!

[YoutubeBorkedMyOldHandle_why]

I've been beating my head against a wall trying to justify spending $400 on an oscilloscope, and here's Dave casually using 2 x $15, 000 scopes and another worth $2000+. Thanks Dave ... I needed that!

[Bllinker]

About that 1k resistive probe: One of my professors who spent his career doing high-speed analog stuff and who started in the 80s (when the access to proper, professional equipment vas very limited over here) made a couple of those probes. He based them on a piece of stripline on FR4 in a plastic syringe to get something like an actual probe (with a very short ground lead, I think he used a thin nail or a needle for that and for the actual probe tip) with the coax attached to the other end of the syringe. So, anyway, he recommends:
-putting a 100-120nF cap right after the input resistor(s) to stop the probe from loading down the circuit at DC (because if you're using this probe you probably don't care about DC)
-if you care about having 20:1 and not 21:1 nominal attenuation, using two 0805 resistors in parallel so that they add up to 950Ω (like a 1k and an 18k)

He claims that the plastic syringe version has a bandwidth of around 1GHz (he used it with a 500MHz oscilloscope), but a better one made with a brass tube instead of the syringe had a bandwidth of around 2.5GHz, limited by the (fairly elastic) coax he used.

Any comment on the use of those caps to limit DC loading of the circuit, Dave?

[martylawson]

The restive transmission line probe is my favorite way to make a built in high speed test point. Because of cell-phones there are some absolutely TINY coax connectors. Many are less than 2.5mm on a side. Add a series resistor and you've got a GHz bandwidth test point for 30-60 cents in < 10mm^2 that securely hooks to the scope with a $5-10 of coax adapters. Easy to AC couple the test point as well, just "tent" a resistor and a cap in series.

[sandalcandal]

Love these educational, tutorial and guide type videos. Here's a comment for the engagement. Keep it coming!

[bostedtap]

Great vlog, nearly everyone, including me (noob), concentrates on the scope settings to solve issues. I remember you showed the special squiggly wire used in their construction.
Always to go back to basics, or advanced for me.
Thanks for sharing.

[pappakilo]

I like your EEVblog HV probe. This time 20 years ago I'd've sold my Mother for one of those for a testing/measurement job we had to do at very short notice. I might even have included our cat and next door's budgie if somebody had promised next day delivery

[johngreen]

Impedance of a terminated 50 ohm coax is a flat 50 ohm resistance (none of that 100pF bollocks). I recommend using another 50 ohm resistor at the input of the coax to dissipate any reflections scope termination might have produced (that will halve the gain, though) and add a good quality dc blocking cap. No need to build a new cable, just modify an SMA connector and screw it into any SMA/3.5mm cable.

[sanjursan]

With a 10X probe and an analog scope with a best volts/div of 5mv it is not much fun trying to measure DC ripple! I use an old analog Hp 412A chopper circuit meter which goes down to 1 millivolt FULL SCALE. It is a lovely, amazingly accurate unit with six ranges below 1 volt! Hypnotic to watch that needle dancing back and forth.

[spicemasterii]

KEYSIGHT.
Eevblog has come a long way from Rigols.
Congrats on your success and an amazing channel, Dave.

[jeffm]

Good video, glad to see some of the older style content back.

[PilotPlater]

Coax transmission lines, Dave you're approaching the territory of RF woowoo magic!

[TheCodr]

The awesome crazy Aussie guy. Keep up the great work bud

[JesusvonNazaret]

A couple years ago Rigol had the best bang for buck in entry level 4 channel scopes, now there are so many new affordable scopes on the market and I wonder which one would be the best bang for buck (with the least amount of annoying "features"). I think there is room and demand for such a comparison video every 5 years or so.

[originalgrantbob]

Thanks Dave. Good explanations and I'm sure a reference I'll end up coming back to.

[TobyRobb]

From my learning about amateur radio coax versus ladder line, you cant expect the shield to fluctuate with AC. It should be tied to ground and the centre pin should go positive and negative with respect to it. With separate conductors EG ladder line, both conductors can go positive or negative. Hence the need for a balun when going between conductor types..

[nicksokolov]

Good work Dave...
I am not immune from asking "stupid question" when looking at circuit.
In my 60ies I make occasional 20y old mistake - no one is immune.
I have 4 of those type probes.. one is differential, one is current - all purchased away from my wifes asking ; and how much was that toy, haven't you got enough!!!
Between you and I Dave one can never have enough probes.
Currently Trying to fix (4off) EPSON theater projector EH-TW5700 with no EPSON repair center manual
anyway I need to fill in time after 65y+ until the elevator to a pub with warm (or no ) beer ....Pub run by guy named Old Nick
It's all fun - keep up your blogs It keeps me going.
I agree...Good enough for Australia and Gina Rinehart

[terrygould]

More videos like this please! Been missing your tutorials and equipment demos etc. Keep up the good work!

[pawpawpascal]

(as a relative newb here) I love these videos that tee off a full day of Dave videos in the links 😸