Amplified Shunt for Ampere to nA measurements

[@MalagasOnFire]

This test box is very cheap , neat, simple, and suitable also for multimeters that have no current input such as the Fluke 101.

[@SebastianScholle]

Nice little tool! Would be nice if you could post a schematic of your amp box.

[@joesmith-je3tq]

Maybe you could watch the video starting around 3:50. Or do you not understand how to read a datasheet and need help selecting part values? If the later, I would just Google op-amps, get the data sheet and read it then start playing. You will be much further ahead this way than me spoon feeding you a bunch of values. Good luck and have fun with it.

[@SebastianScholle]

Hey Joe. Mind if I make a schematic out of it? Will post it here for everyone else?

[@joesmith-je3tq]

As long as you are not trying to sell anything off of my channel, I don't care. A better area may be to post in on the EEVBLOG site as my channel is pretty small.

[@SebastianScholle]

not selling. Just open sourcing. eevblog is a good place to discuss it too. Thanks Joe.

[@JackZimmermann]

Great stuff as usual! Looks like you can measure between a larger range, like µA to mA without problems? I'm building one.

[@joesmith-je3tq]

With the battery that was in there, it starts to go non-linear around 3 volts. So, for example in the uA range it's upper end is about +/-3mA. The voltage drop when switching between ranges will always be limited by the back to back diodes. I used the 1051 for it's wide operating voltage. You could come up with your own combo easy enough. Maybe get some better resistors or add some trimmers. Fuse could be removed which would help the mA range. Good luck. Be sure and post your results.

[@JackZimmermann]

Yes, I'll do some experiments when I get my crazy NTP-server project finished. www.jackenhack.com/ntp-server-extreme-accuracy-for-under-200/ Could be a cool Open-Source Hardware thing. Thanks again.

[@joesmith-je3tq]

I checked out your blog. Some nice projects you have going on. I liked the one about the coax. Good stuff.

[@JackZimmermann]

Coming from you sir, I take that as a great compliment! Learned the coax trick from a Ham-operator. There's a lot of knowledge to get from those guys. And my father was a Ham-nut. I like the rf part of it, but listening? not so much... :) I'm still thinking of the video you did about some older FPGA projects you've done. Any followups?

[@joesmith-je3tq]

I'm in the same boat. I used to have a HAM license when I was a kid. I watched a video of Steve Wozniak and there was a picture in there of him playing with an old Halcrafters radio. I started out with that same radio. Crystal controlled. Sadly, most of the people I knew were more interested in buying the latest Japanese radios and talking. Low bands were like CB radio and I lost interest. I still have my old tube Drake HF radio and even have my Vibroplex. The last FPGA project I worked on for home was that Hardware in the Loop (HIL) simulator. I can't afford D-SPACEs products for home fun. Even that's been a few years now. When I finally pulled my old Windows XP P4 desktop PC a few month back, I had to rewrite all to low level code which was in C. The new PC was so fast (really fast), I could just write everything in LabVIEW which included the interrupt handler. I picked up that Arty board to play with Vivado about a year ago and even it sits idle. Only so much time.

[@rubenuspv]

Daves uCurrent didn't have any fuse (to avoid the extra burden voltage) and have a schematic published on his website: eevblog . com/files/uCurrentRev5schematic.pdf (sorry for cutting the url, just to avoid be marked as spam). Great work, I'm building one!.

[@joesmith-je3tq]

Same three shunt values, same 100X gain, this makes sense. He buffered the ground and I was too cheap. Much better parts than mine. I'm sure his does a much better job than my morning construction on perf board. But if you just needed something in the ballpark, no reason you could not toss something together and get reasonable results. I wonder how his 121GW (new meter) will be by comparison. I am assuming it would replace his uCurrent Gold but I don't think he has posted a lot of details yet.

[@ohmedarick1]

Great Project Thanks