DIY Homebrew Oscilloscope Current Probe - Page 1
Forum section: electronics / projects

author: Zog
author_rank: Regular Contributor
timestamp: May 20, 2018, 02:02:57 am
content: I have heard mention that's it's possible to make an el'cheapo oscilloscope current probe from ferrite beads.Anyone ever done this before ?Or know where I can find information for it ?I would like to make one for my Rigol DS1054Z

author: tautech
author_rank: Super Contributor
timestamp: May 20, 2018, 02:05:44 am
content: https://www.google.co.nz/search?q=diy+oscilloscope+current+probe&rlz=1C1CHBF_enNZ760NZ760&oq=diy+oscilloscope+current+probe&aqs=chrome..69i57j69i60.5869j0j8&sourceid=chrome&ie=UTF-8

author: CopperCone
author_rank: Super Contributor
timestamp: May 20, 2018, 03:22:43 am
content: you can take a ferrite clamp put like 6 turns of wire around it and use that.but unless you got a signal generator to kinda at least get an idea of the transfer function it might be difficult to use.

author: Zog
author_rank: Regular Contributor
timestamp: May 20, 2018, 11:23:38 am
content: thanks guys

author: ocset
author_rank: Super Contributor
timestamp: May 20, 2018, 12:37:38 pm
content: current probe: It depends what current level, and what bandwidth you want, but current probes are generally not cheap.Cheapo means sense resistors...or hall sensors if its higher current, or you can use current sense transformers which are cheap if used certain ways in smps.Eg as attached for current sense transformers in smps. Its an LTspice sim which is a free download

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: May 20, 2018, 12:59:50 pm
content: Why not use Allegero current sensor chips, like the ACSxx series! some models can do till 1MHz with up to about 50A

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 21, 2018, 07:05:43 am
content: Are you thinking about a small probe for sniffing magnetic fields around a PCB trace, or for measuring high current stuff such as the other posts mentioned here?AC or DC?Bandwidth?Accuracy?The UNI-T UT210E is a nice clamp meter with an (Exceptional !!!) low current 2A DC range.The Youtube guy who blows up all multimeters while "testing" them 4kV spikes once did a vid about this clamp meter.He put in an opamp and connector and got about 2kHz bandwidth out of it.The extra opamp is probably not needed, it's already got a low offset opamp near the current sensor.

author: tautech
author_rank: Super Contributor
timestamp: May 21, 2018, 07:13:10 am
content: Quote from: Doctorandus_P on May 21, 2018, 07:05:43 amThat YT guy is member Joe Smith and you can see all his DMM tests here:https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/

author: czbaterka
author_rank: Contributor
timestamp: March 19, 2025, 12:29:40 pm
content: Quote from: tautech on May 20, 2018, 02:05:44 amFun fact: I used exactly the same search query and first result was this eevblog postRECURSION BABY!

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: March 19, 2025, 09:22:58 pm
content: Another useful current probe is the Rogowski probe. It needs an integrator. I haven't looked, but it might be possible to do that with the math functions of a modern scope.https://www.pmk.de/web/editor/files/The%20Basics%20of%20Rogowski%20Coil%20Current%20Probe_Iwatsu%20AppNote.pdf