USB Isolator - Page 1
Forum section: electronics / general

author: Foxxz
author_rank: Regular Contributor
timestamp: January 24, 2021, 11:23:31 pm
content: Anyone use a USB isolator for high voltage?The backstory here is in the winter my house seems to generate alot of static. When sitting down at my computer I would get zapped touching my keyboard and sometimes the keyboard would disconnect and only by unplugging it and plugging it back in would the problem be fixed. I since added a USB isolator (https://www.amazon.com/dp/B079M2ML44/) and I no longer get zapped. However, the keyboard will often require unplugging and reconnecting to begin working.I had seen a better rated isolator at some point but it seems I can no longer find it. Recommendations would be appreciated.

author: nightfire
author_rank: Frequent Contributor
timestamp: January 24, 2021, 11:44:20 pm
content: Industrial quality:https://www.wut.de/e-8wwww-11-inde-000.php(German company, I don't know how about distribution in the US)Other thought: In Winter due to heating and cold air from outside (which has no water in below 0 deg. Celsius) the air can be very dry and below 20 % rel. humidity static issues will arise.Getting the air above 20% (preferrably somewhere towards 50% which is deemed good by doctors) will reduce that potential for static (and infections due to dry noses...) significantly.

author: Nominal Animal
author_rank: Super Contributor
timestamp: January 25, 2021, 11:50:15 pm
content: I would suggest not just an USB isolator, but also a separate safe potential grounding line from the keyboard/USB connector chassis to a grounding point, through a big beefy resistor (100k? 1M? Preferably > 1W rating, so it can handle the high voltage).The idea is to provide a path to ground for the potential to dissipate through, without disturbing the electronics.Even better, install a conductive plate, maybe thin aluminium sheet (the nonconductive aluminium oxide layer doesn't matter) for your palms to rest on, or that you always touch before anything else on the machine, that dissipates the static charge to ground (like the computer chassis) through a suitable resistor.If you have a whiteboard, and in the winter season get zapped by the aluminium shelf you hold the pens in, you can do the same to that too: connect a beefy resistor to the aluminium shelf, and then a single wire from the other end of the resistor to a grounding point. Works very well: touching the shelf will then dissipate any potential difference (static charge) "slowly"/safely through the resistor, and you won't feel a thing.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: January 30, 2021, 10:42:46 am
content: Maybe adding a few of those splitable ferrite cores on the keyboard cable are enough to spread the energy a bit so it gets dissipated through the screening of the USB cable without causing disruptions.

author: Alti
author_rank: Frequent Contributor
timestamp: January 30, 2021, 11:32:42 am
content: I think it is a bad idea to use isolator. USB shield should be earthed.Since you get electrostatically charged, the problem is you, not the keyboard. I'd suggest touching some earthed resistor before you approach a keyboard. Maybe glue 10M to the keyboard/USB and touch it. Or maybe put ESD mat (earthed through a resistor of course).I tried to solve same issue with my trampoline but the voltage and capacitance is so high that 2M2 resistor (THT 0.25W) was arcing over sometimes. I think several 1M resistors in series could have been a more reliable option.