Oscilloscope Differential probes - Page 1
Forum section: electronics / testgear

author: grumss
author_rank: Contributor
timestamp: February 04, 2021, 11:45:25 am
content: Hi all,Looking around, i havnt found an economical option for differential oscilloscope probes..Looks to me that there isnt much to the circuits and cant believe there isnt 100's of people making them available (i would myself if i was still designing and sending out kits)..Maybe a good idea for you guys that are still keen?cheers, VK3XDK

author: joeqsmith
author_rank: Super Contributor
timestamp: February 04, 2021, 12:11:49 pm
content: Quote from: grumss on February 04, 2021, 11:45:25 amI watched several videos where people will buy them just to look at the AC lines of their home. Really odd when you consider, what's the point or just pull an old transformer type walwart from the trash bin to provide the step down and isolation.Outside of that group, what would be the design goals? I doubt you could make a generic, one size fits all probe. Of course, you could just roll your own.If you just want to look at the AC line, a transformer may be a much better option

author: grumss
author_rank: Contributor
timestamp: February 04, 2021, 12:19:05 pm
content: I'm thinking that it doesnt have to be special, just something that can be used to fault find ya typical switchmode supply without having to stress too much... Thats the only reason i'm interested in the first place..I'm finding it hard to part with $250 or more $Aus for something that should be cheap... OP amp or 2 and a few resistorsI really cant be bothered anymore with developing such a circuit, and i wouldnt be happy if it was using a scrap of solder on a protoboardOn a regular basis. Sorry to be a lazy "snob"I designed and sent out stuff like this for years and am very over it!

author: joeqsmith
author_rank: Super Contributor
timestamp: February 04, 2021, 12:49:02 pm
content: Nothing special is hardly a design goal and I don't know what a typical switchmode supply would be. Regardless of your requirements, we now know that $250 is too high for you.Seems like when you consider the time to sort out what the market needs (your special and typical are case and point), come up with a design, documentation, testing, certification, tooling, manufacturing, warranty, supply chains....Maybe something like this $140, 100MHz 1300V probe.https://www.aliexpress.com/item/4001335340029.html?spm=a2g0o.productlist.0.0.213e7999cT7Cfs&algo_pvid=c6a7b429-3a8e-433a-81a2-6da05c9ece8c&algo_expid=c6a7b429-3a8e-433a-81a2-6da05c9ece8c-2&btsid=0bb0623016124427599667055eb519&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

author: ledtester
author_rank: Super Contributor
timestamp: February 04, 2021, 06:06:35 pm
content: Quote from: grumss on February 04, 2021, 12:19:05 pmHow suitable would one of those battery-powered scopes be for that purpose -- i.e. one from FNIRSI or JYE Tech?

author: Kibabalu
author_rank: Regular Contributor
timestamp: February 04, 2021, 07:14:09 pm
content: I have been in a similar mood like the TO: I don't really need one, but I desire one ;-)I bought the 100MHz 70V/700V version of the model posted by joeqsmith:https://www.aliexpress.com/item/1005001963885517.html?spm=a2g0s.9042311.0.0.19874c4dDnHMf5I paid 120€ and received a kick into my ass from my wife for buying unnecessary toysBut now I know, how my line voltage is looking like

author: rvalente
author_rank: Frequent Contributor
timestamp: February 05, 2021, 05:35:06 pm
content: I'm gathering the parts to build this one, so far is the best open source probe I've ever seenhttps://hackaday.io/project/169390-a-10x-100mhz-differential-probe

author: David Hess
author_rank: Super Contributor
timestamp: February 11, 2021, 04:04:32 am
content: What kind of differential probe are you referring to? High voltage? Low voltage? They have significant design differences and low voltage differential probes are less general purpose.I have thought about designing either or both but I usually get by by using add and invert mode and if I need better performance, I have Tektronix 7A13s and 7A22s available.