Updated BOM for µCurrent? - Page 1
Forum section: electronics / beginners

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: March 06, 2024, 03:39:24 am
content: The EEVBlog µCurrent hasn't been in stock for quite some time and who knows whether Dave has the time/energy to setup another production. Because of this I'm thinking of simply having my own µCurrent made however looking at the BOM, I've noticed that many parts are actually no longer available.Has someone created an updated BOM which will nearly meet the original specs?

author: Leuams
author_rank: Contributor
timestamp: March 06, 2024, 09:37:22 am
content: There have been some derivative products that you may want to look into such as the Current Ranger:https://lowpowerlab.com/guide/currentranger/

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: March 06, 2024, 06:03:45 pm
content: I'd rather not purchase that product as it isn't open source.https://www.eevblog.com/forum/testgear/current-ranger-from-lowpowerlab/

author: mwb1100
author_rank: Frequent Contributor
timestamp: March 06, 2024, 07:16:38 pm
content: Another derivative that is open source:https://github.com/nfhw/tinycurrent

author: Kleinstein
author_rank: Super Contributor
timestamp: March 06, 2024, 07:25:56 pm
content: The main critical part in the µCurrent is the max4239 AZ-OPamp with a good bandwidth and low offset. Everything else should be easy to replace with different parts / manufacturers.For the resistors one has to see what is available at a reasonable price. The search functions at the suppliers should help here.For the µCurrent there is sometimes the misconception it could be a good solution for small currents. For the really small currents (e.g. < 10 nA) the better solution is often a transimpedance amplifier configuration and using a more normal (non AZ) amplifier.IFAIK the lower current ranges have no protection with clamping diodes - I would add that option to a PCB if I would build a version.Ideally one may want more shunts (e.g. 1:10 or at least 1:100 steps) to choose from. The current solution is OK for some currents, but not for all. The 1:1000 steps are just to large to cover everything in between. It would also make sense to have a case with no shunt and thus the option to use it as an amplifer for low voltages (e.g. a thermocouple).The nice point is having DC accurate gain with low offset. This may help to add low burden current ranges to a DMM, but is less important when used with a scope. With a scope one has a DC offset from the sope anyway and noise is often more relevant the the offset.

author: Leuams
author_rank: Contributor
timestamp: March 06, 2024, 10:18:55 pm
content: Quote from: LooseJunkHater on March 06, 2024, 06:03:45 pmI was not aware of the issues with that product, good to know.

author: linux-works
author_rank: Super Contributor
timestamp: September 24, 2024, 12:15:36 pm
content: I'm in need of an auto-switching microcurrent style box. I have the mc gold but I really do want it to auto scale (quickly) as the power modes will be all over the place when doing devel on controller sleep modes.I was about to order the ranger but I was not aware they stopped supporting it via open code. (then again, there was at least 1 fork and as long as it works, I can probably fix bugs if I need to).but I'm wondering what it would take to do the auto switch of the scale on the eevblog box. maybe something that watches for the range (a 2nd cpu?) and then throws that 3 pos switch in real time?has anyone tried doing that? I have an actual mc-gold and I'm happy to hack it, but I do need that autorange stuff.ideas?