Current transformer for ESD testing - Page 1
Forum section: electronics / testgear

author: Geoff
author_rank: Contributor
timestamp: July 29, 2024, 12:57:17 pm
content: Is there a cheap current transformer suitable for ESD testing, or a DIY option?In mil-std-883 they suggest using a Tektronix ct1 current probe, but it's out of my budget.The current transformer for ESD testing needs a bandwidth of 350MHz min.Or would it do, to destructive test an astable multivibrator circuit using a 4011 NAND Gate Chip? Hitting it, repeatedly, with an ESD, then seeing if it still works.I'm looking for a way to test my protection circuit for the GPIO's on an ESP32-C3 modal.Ref:Page 468 METHOD 3015.7https://scipp.ucsc.edu/groups/fermi/electronics/mil-std-883.pdf

author: joeqsmith
author_rank: Super Contributor
timestamp: July 29, 2024, 01:09:07 pm
content: Quote from: Geoff on July 29, 2024, 12:57:17 pmJust to be clear, you have a gun that meets the standard you are required to test to. You want to verify that the gun meets this standard for some reason or another. You want a cheap way to measure it. I assume this if for some sort of pre-compliance test so have a lot of freedom.If the gun was rented, you may be able to rent the target as well. You may also be able to send the gun in for calibration. If you want to construct a target, the standards cover that.

author: Geoff
author_rank: Contributor
timestamp: July 29, 2024, 01:37:59 pm
content: I'm interested in circuit design and reliability, not so much compliance testing."Just to be clear, you have a gun that meets the standard you are required to test to."No, I have a very low humidity room and some woollen cloth as well as a plastic pipe. And a bug zapper.If needed, I could DIY something with more punch."I assume this if for some sort of pre-compliance test so have a lot of freedom."No, but I would be happy if I could do better than the requirements.

author: selcuk
author_rank: Frequent Contributor
timestamp: July 29, 2024, 01:57:12 pm
content: If you need another cheap solution for ESD testing, you may read chapter 3.7.3 from this document:https://www.emcstandards.co.uk/files/d-i-y_emc_testing_2001_part_3_surge_immunity.pdfDon't forget to use it with metal planes over the table and ground like in Figure 3S. It will zap on everything near about a few centimeters if it cannot find a ground return. Be careful. I'm connecting the metal on the ground to protective earth as well. This is not shown on figure 3S.

author: joeqsmith
author_rank: Super Contributor
timestamp: July 29, 2024, 02:15:58 pm
content: Good paper. Many here should find that helpful.

author: joeqsmith
author_rank: Super Contributor
timestamp: July 29, 2024, 02:37:14 pm
content: Quote from: Geoff on July 29, 2024, 01:37:59 pmI doubt you will get repeatable results with cloth and plastic pipes. I played a bit with an electronic fly swatter. The better choice I found was a piezo gas grill starter doing a direct contact. The problem with these is each one is unique. Meaning you can't buy two of the same product and expect the same results. I use one to test multimeters and the other problem from at least the one I use is the waveform is a mile off the standard. I tried to find where I posted about it here and came across some other links that may be of interest. Looks like I never posted about it, but I did cover it during the first part of my video on the UNI-T UT181A linked below.https://www.eevblog.com/forum/projects/bbq-electronic-igniter-it-generates-dc-or-ac-sparks/https://www.eevblog.com/forum/projects/mosfet-switch-for-diy-esd-gun/https://www.eevblog.com/forum/projects/diy-esd-gun-357043/