tinyCurrent from n-fuse requires direct wire transfer to purchase, have you DIY? - Page 1
Forum section: electronics / testgear

author: the_cake_is_a_lie
author_rank: Contributor
timestamp: December 24, 2023, 06:41:45 pm
content: I didn't want to buy CurrentRanger since it violates Dave's CC-BY-SA license but tinyCurrent seems good enough for my purposes. Well, not so much after shipping and my bank's $25 WIRE TRANSFER FEE, so about $140 total USD. I see n-fuse has aneBay storewhere I can pay with whatever for about $130, after currency conversion.At over $100, I could just get a Power Profiler II with nice software if I don't need to measure under 100nA.That said, tinyCurrent is open source. Has anyone successfully built it? Not sure how much soldering skill is required for a sensitive measurement tool, or how to calibrate and I don't have a reflow oven.The img tag doesn't work for me so I edited to upload the screenshot instead.

author: mawyatt
author_rank: Super Contributor
timestamp: December 24, 2023, 07:15:09 pm
content: PayPal?Best,

author: Kleinstein
author_rank: Super Contributor
timestamp: December 24, 2023, 09:00:29 pm
content: The required soldering skill should not be that high. The main point would be the (likely 3) OPs in a SOT23-5 (or similar) case. One could use the cheap one for the virtual ground for some training to get used to it when it comes to the slightly more expensive ones. The other parts (at least Daves version) should be easy / beginner level and only a challange with poor eye sight. If really needed an one is willing to draw / modify the PCB one may also use easier to solder parts (only the MAX4239 is a slight challange as it is only available in the relatively small case - it is still one of the best bets for low offset and low bias and also relatively fast for the low power).Depending on the actual needs a different DIY solution may be the better choice.For the calibration, I would not expect any - they just use low tolerance resistors and hope that soldering does not change much. The offset is easy to check: open circuit naturally results in no current.One can do a change with a reasonable good DMM and resistors to set the low currents.With foreign offers the shipping and payment costs may be significant, but one is not fored to buy if you don't like it.

author: the_cake_is_a_lie
author_rank: Contributor
timestamp: December 28, 2023, 11:41:39 pm
content: Thanks for the tips! I did see the video of Dave assemble a bunch of µCurrent™ GOLDs like it was nothing but didn't grasp the skill required. SOT23-5 is less ant-sized than the SOT-363s components I have sitting around so can manage. I was also thinking of getting a stereo zoom microscope for PCBs to help with SMDs.That's a good point, to set the zero from no current input. I was thinking more of how to get a precise 100pA to 1nA current supply, but I could just be precise on the R and V fronts with an LCR meter with Kelvin clips and a lab bench power supply. V/R = I and compare the calculated I to DIY tinyCurrent. Maybe I make two and sell the spare to cover my BOM costs.I'm not a PayPal fan, more using my own credit card that I can dispute on if the device doesn't work, comes obviously damaged or I receive the wrong product. And...it's the principle of the thingwire transfer to buy electronics? This isn't paying a lawyer's retainer to get divorced.

author: Someone
author_rank: Super Contributor
timestamp: December 29, 2023, 12:20:49 am
content: Quote from: the_cake_is_a_lie on December 28, 2023, 11:41:39 pmFrom the other side of the equation:Customers maliciously using chargeback for change of mind (or worse).US banks charging high fees for transfers (even domestically).Some people (mostly in other countries)preferwire transfer, and as above you have the choice to eBay/PayPal via a credit card if you want those protections (which cost money, hence the "fees").