Author Topic: Why are scope probes so damn big?  (Read 6596 times)

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Offline alanambroseTopic starter

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Why are scope probes so damn big?
« on: November 07, 2018, 06:21:43 pm »
Duh, we're working on these little things 1mm scale, and the damn probe is over 6 inches long with all the leverage that goes with that. Is this a design left over from the valve radio era that hasn't been updated?

Alan
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Offline brybot

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Re: Why are scope probes so damn big?
« Reply #1 on: November 07, 2018, 06:33:56 pm »
It's probably for human ergonomics. Anytime I'm working with really tiny stuff, I change out the tip to get the ground loop very small and close to what I'm measuring. Or build something custom.
 

Online ataradov

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Re: Why are scope probes so damn big?
« Reply #2 on: November 07, 2018, 06:39:15 pm »
Do you have a better design in mind? Propose one. They are inconvenient because nobody came up with a more convenient idea.
Alex
 

Offline jeroen79

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Re: Why are scope probes so damn big?
« Reply #3 on: November 07, 2018, 06:52:11 pm »
Do you have a better design in mind?


But then:
It's probably for human ergonomics.
You need something to hold comfortably and the size and shape of a pen seems to be right.
 

Online ataradov

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Re: Why are scope probes so damn big?
« Reply #4 on: November 07, 2018, 06:54:25 pm »
This is not a design. How would you hold this? The leverage is now in the cable. How does this help?

Probes are already about the size of a pen. Tektronix has smaller than usual probes, so you may want to look into that.
Alex
 

Offline alm

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Re: Why are scope probes so damn big?
« Reply #5 on: November 07, 2018, 07:15:18 pm »
Tektronix had some smaller scope probes, like the 2.5mm ones Mike is showing in this video. Their current passive probes are slightly larger, but still smaller than common Rigol / Siglent / etc probes. They also made some even smaller probes specifically for SMT. But quite fragile. For some reason, brands like Rigol only cloned the 5mm form factor that was introduced in the sixties.
« Last Edit: November 07, 2018, 07:18:17 pm by alm »
 

Offline jeroen79

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Re: Why are scope probes so damn big?
« Reply #6 on: November 07, 2018, 07:18:43 pm »
It is a design for the smallest possible probe as the OP asked if probes could be smaller.
If it was for a commercial product I would have it finished a bit neater with a proper tip and something to attach a ground lead/clip.
If it is too flexible you clad it with an inch or two of hard plastic.

And yes, today's probes evolved to the size of a thick pen because that is a good ergonomic shape.
 

Offline bitseeker

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Re: Why are scope probes so damn big?
« Reply #7 on: November 07, 2018, 07:19:48 pm »
TEA is the way. | TEA Time channel
 

Online tautech

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Re: Why are scope probes so damn big?
« Reply #8 on: November 07, 2018, 08:08:46 pm »
Duh, we're working on these little things 1mm scale, and the damn probe is over 6 inches long with all the leverage that goes with that. Is this a design left over from the valve radio era that hasn't been updated?

Alan
You're always gunna have connectivity issues with SMD, get used to it and make the changes in gear on hand to allow for it.
For a start look for a small lot of these Tek grabbers:
https://www.ebay.com/itm/Tektronix-020-3043-00-Test-Probes-Grabber-Adapter-Kit-Pack-of-20-050-CTR/112972917228?epid=1309976830&hash=item1a4db5e9ec:g:wOIAAOSwIhFa6dpw

Get these ^ ones, not some of their later cheaper offerings. Make up some flying leads with tinned and/or looped ends to connect your std probes to.
There are other various style SMD grabbers available and some @ $1/dozen but they are shite so overlook them.

Buying test gear is just the start, cables, grabbers, attenuators, and so on will keep tapping the back pocket...........
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Offline joeqsmith

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Re: Why are scope probes so damn big?
« Reply #9 on: November 08, 2018, 04:25:06 am »
Duh, we're working on these little things 1mm scale, and the damn probe is over 6 inches long with all the leverage that goes with that. Is this a design left over from the valve radio era that hasn't been updated?

Alan

 :-DD :-DD  Well I can't say I disagree with you.  Maybe not quite as bad as the tube era but it there is always room for improvement.  Let me know when you come out with something.

Offline KL27x

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Re: Why are scope probes so damn big?
« Reply #10 on: November 08, 2018, 10:19:30 am »
At first, I had the same feelings. Early on, I bought a cheap set of scope probes and cut the entire probes off and soldered female pin sockets on the ends. Then I could stick these onto test pins or stick pins in there to wrap wire onto for soldering connections. Obviously no good for high voltages or frequencies, but something was wrong. Even the weight of the wire is a lot for a really small board.

What I eventually learned to do with the micro tiny boards is to bring the signals I'm interested in and port them out to a row of pinheader. Have everything glued down to a single piece of fr-4 or plywood or something. Then you can stick a piece of label tape down next to the header and name all these signals. Now you can quickly switch 2 or more standard full size probes between various signals of interest that you might need to see in relation to each other. Or have one probe hooked to a pin, and use the other to touch-probe the circuit. When you're working on such small stuff, this is even better. It takes time to work on tiny stuff, and putting some extra work in just the once, upfront, can save a lot of frustration later. So ultimately, the only tiny probe you need is disposable. It's 30AWG kynar wire and solder.
« Last Edit: November 08, 2018, 10:36:14 am by KL27x »
 

Online Berni

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Re: Why are scope probes so damn big?
« Reply #11 on: November 08, 2018, 10:28:34 am »
They make small probes too, like this for example:
https://www.keysight.com/en/pd-1661742-pn-N2874A/passive-probe-101-15-ghz-13-m?cc=US&lc=eng

I have a similar set of probes from Agilent and they are indeed very nice probes.

It doesn't make sense making them smaller than this because then they can no longer be held like a pen, and you don't really gain much from going smaller. If you need a tiny probe to solder in then just cut the end off a BNC cable.
 

Offline malagas_on_fire

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Re: Why are scope probes so damn big?
« Reply #12 on: November 08, 2018, 11:46:51 am »
Yes probe master also do some small probes with hooks that reminds the ones used in logic analyzers. The price is not so small :P

https://www.amazon.com/Probe-Master-6164-Oscilloscope-Grabbers/dp/B01D3QX9CI

https://probemaster.com/6164-dual-lead-scope-probe/

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Offline In Vacuo Veritas

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Re: Why are scope probes so damn big?
« Reply #13 on: November 08, 2018, 03:10:07 pm »
Duh, we're working on these little things 1mm scale, and the damn probe is over 6 inches long with all the leverage that goes with that. Is this a design left over from the valve radio era that hasn't been updated?

Alan

Probes from that time are even bigger... HP used to make small scope probes but they were fragile and fell apart like confetti. I don't know why.

It's also the fact that most circuits now are digital and have self test makes probing and scopes in general much less useful than they used to be.

Logic analyzers come with small clips.
 

Offline IanMacdonald

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Re: Why are scope probes so damn big?
« Reply #14 on: November 08, 2018, 04:23:04 pm »
More of a problem are 'shouldered' DMM probes that can't be put into adjacent sockets.
 

Offline In Vacuo Veritas

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Re: Why are scope probes so damn big?
« Reply #15 on: November 08, 2018, 04:35:23 pm »
HP 10400A is the part number.
 

Online Berni

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Re: Why are scope probes so damn big?
« Reply #16 on: November 08, 2018, 06:24:57 pm »
Duh, we're working on these little things 1mm scale, and the damn probe is over 6 inches long with all the leverage that goes with that. Is this a design left over from the valve radio era that hasn't been updated?

Alan

Probes from that time are even bigger... HP used to make small scope probes but they were fragile and fell apart like confetti. I don't know why.

It's also the fact that most circuits now are digital and have self test makes probing and scopes in general much less useful than they used to be.

Logic analyzers come with small clips.

I have two scopes with MSO capability but i rarely ever used it. These days serial interfaces are more common so you can usually get away with 4 analog channels just fine. The analog channels give you more information about the waveform anyway. You can see if the edges look fine, you can see it floating, you can see weird things if two pins short together etc.

I find SMD resistors or 1.27mm pitch chips pretty easy to probe with a normal scope probe. If i need to probe smaller things, or i need to hold a probe on a point for longer then i simply solder a tiny wire to the point and then grab that wire using the 'wichhat' clip for the probe. You can probe 0.5mm pitch chips too but its kinda dicky and you often end up shorting to the pins next to it, but for just quickly checking if a pin on there is getting clock its certainly good enough.
 

Offline In Vacuo Veritas

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Re: Why are scope probes so damn big?
« Reply #17 on: November 08, 2018, 07:49:25 pm »
...and they're still expensive! Wow. I wonder if there's a market for miniature scope probes, and why no one cares about it?

I'd expect Chinese manufacturers to sense that market and in one week we'd have not only a design but orderable products!
 

Offline AndyC_772

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Re: Why are scope probes so damn big?
« Reply #18 on: November 08, 2018, 07:55:32 pm »
I miss the Tektronix P6139A probes that I used to have with my old scope. They were 500 MHz bandwidth and much smaller than the clumsy Agilent probes I have now.

Offline malagas_on_fire

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Re: Why are scope probes so damn big?
« Reply #19 on: November 08, 2018, 09:24:45 pm »
...and they're still expensive! Wow. I wonder if there's a market for miniature scope probes, and why no one cares about it?

I'd expect Chinese manufacturers to sense that market and in one week we'd have not only a design but orderable products!

Try these for size ..:

https://ebay.us/TsUEth

or already wired ...

https://ebay.us/3DCb3j
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Offline joeqsmith

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Re: Why are scope probes so damn big?
« Reply #20 on: November 09, 2018, 04:04:15 am »
I use some Pomona 6353 micro clips that are similar to what Tautech shows.  Even these are fairly large and then you still need to connect your probe to them.  Maybe for slow stuff you could get away with it.   

I was playing around with a cheap Xilinx eval board and probing was a problem.  Not pretty but was just trying to get a feel for the part. 
https://www.eevblog.com/forum/microcontrollers/typical-speed-of-fpgas/msg1282290/#msg1282290

I wouldn't mind having a good probe holder but as we continue to move toward BGAs, even that is less useful.    They make some really nice ones that would cost more than my scopes. 

****

Similar probing on some old 7400 logic....

https://www.eevblog.com/forum/projects/waveforms-in-a-74ls04-ring-oscillator/75/
« Last Edit: November 09, 2018, 04:08:11 am by joeqsmith »
 

Offline malagas_on_fire

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Re: Why are scope probes so damn big?
« Reply #21 on: November 09, 2018, 02:09:32 pm »
I think the probe issue and i might be wrong what i'm about to say, is to use externa test points when developing / prototyping a new board and then skip them as they get passed. This involves  to extra cost in building a prototype PCB bigger and then another more compact, but saves time in probing and extra tiny probes. The strandard ones feels confortable in the hands and prevents that tiny coax cable to be mangled so soon.


 
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Offline mikeselectricstuff

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Re: Why are scope probes so damn big?
« Reply #22 on: November 09, 2018, 02:20:16 pm »
I miss the Tektronix P6139A probes that I used to have with my old scope. They were 500 MHz bandwidth and much smaller than the clumsy Agilent probes I have now.
I've always used P6131's and left whatever came with scopes in their bags. Much smaller & lighter, and thinner, lighter cables.
You can poke the tip into a PCB hole and hang the lead over the desk light , giving enough pressure for contact but not to damage the tip (mostly - they wil bend a few times before snapping)- very handy.

you can also tidy them like this when not in use.
 
 
« Last Edit: November 09, 2018, 02:22:22 pm by mikeselectricstuff »
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Offline In Vacuo Veritas

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Re: Why are scope probes so damn big?
« Reply #23 on: November 09, 2018, 03:51:19 pm »
Why isn't there a cheap and cheerful universal articulated probe holder? This will utterly change the world forever. It should be completely and totally trivial to do.
So I won't do it.
 
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Offline KrudyZ

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Re: Why are scope probes so damn big?
« Reply #24 on: November 09, 2018, 04:11:10 pm »
Tektronix P6562A and P6563A are very small passive probes that can be placed on 0.1" headers.
They sometimes can be had for reasonable prices on ebay (but not at the moment)...
 


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