EEVblog #1368 - Active Oscilloscope Probes COMPARED (Part 2)

[EEVblog]

Part 2, this time looking at different types of active oscillocope probes.
Single ended active FET probes, differential active FET probes, current clamp probes, high voltage differential probes, positional current probes, and EMC magnetic and electric field probes.

2MHz Current clamp probe: https://www.eevblog.com/product/cp2100b/
Active FET probe: https://amzn.to/3oq0Q8g
EMC probe set: https://amzn.to/39oEqAh

[sibeen]

You missed a trick there, Dave. The Keysight scope can certainly be programmed for a 21x gain for a probe, you just need to use the touchscreen

[TheNewLab]

Aiyaaaaaa.

Now I need to get a touch screen oscilloscope??  Great, she's serving the papers...soon to be divorced...

THanks for part two. I dropped the funds for some diff. probes awhile back, and you've given some ideas in how else I can use it.

[Paul Bryson]

I discovered a useful tip for using the scope probe spring ground contacts - to prevent slipping.  I solder a 1mm-2mm "crimp bead" (a jewelry finding from Hobby Lobby) to a nearby decoupling cap.  They are very cheap - about $0.01 each.




http://www.brysonics.com/one-cool-trick-for-probing-high-frequency-signals/

[johnh]

Must not be caught raiding my wife jewelry making findings looking for crimp tubes

[BrianHG]

I know that Agilent has an LED, but I like the slimness of my Tek 1.5&1GHz probes of 15 years ago.  With .2 inch width spacing, you can place all 4 probe heads on headers directly in under an inch of PCB area, While you can have the signal pin and GND 0.1inch spaced apart.  No wiring to PCB.

They also had these plastic 'hair comb' tips which allowed you to flawlessly tap any single TQFP pin perfectly without any adjacent shorting and hold it there.

[jbritton]

Dave, what do you think of https://www.crowdsupply.com/weston-braun/little-bee

[G7PSK]

Quite some years ago now I had an active scope probe that had a valve in it, I picked it up at an auction and as at the time I did not have a scope I sold it, I suppose that it is the equivalent of an FET probe but probably would work at higher voltages. I cannot remember what the vale type was other than it was very small but it still made for a very fat probe.

[SilverSolder]

Quite some years ago now I had an active scope probe that had a valve in it, I picked it up at an auction and as at the time I did not have a scope I sold it, I suppose that it is the equivalent of an FET probe but probably would work at higher voltages. I cannot remember what the vale type was other than it was very small but it still made for a very fat probe.

Keep your hands warm too, on a cold winter's eve!

[faraday]

Dave, what do you think of https://www.crowdsupply.com/weston-braun/little-bee

It has 15% accuracy compared to I-prober 520 3%.

[SilverSolder]

The venerable uCurrent deserves a mention...  it works fine as a current sensor, with DC-100KHz flat response (and low burden voltage, obviously), it is useful for many more things than just measuring CPU standby currents...

[faraday]

How about P6201 

Not bad response from 250Mhz scope BTW

[MarkL]

You missed a trick there, Dave. The Keysight scope can certainly be programmed for a 21x gain for a probe, you just need to use the touchscreen

Another trick: For Agilent/Keysight users with the non-touchscreen A-series, you can also switch from ratio into dB mode and dial up 26.40 dB.  It's close enough the actual value of log10(21)*20 = 26.44.  The scope displays the equivalent ratio as you adjust the dB, so you don't need to get out the calculator.

Annoyingly, the SCPI interface will accept the actual 21:1 ratio.  It just can't be done directly from the front panel on these models.