Author Topic: Current Source for DIY Multimeter  (Read 1674 times)

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Offline akowalczykTopic starter

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Current Source for DIY Multimeter
« on: May 15, 2019, 07:02:45 am »
Hello!

I'm working on a 4.5 digit multimeter design and am not sure what the best current source would be for the ohms range.

I have +/- 5V, but that can change if a better solution is out there if I need to bump the voltage a bit (it's battery powered but I'd be OK boosting to get higher voltages)

Right now I am looking at using this reference design with a REF200 current source providing a regulated 100uA from this app note:
http://www.ti.com/lit/an/sboa046/sboa046.pdf



Although the app note mentions being able to program the output current, I'm running into issues with trying to source anything other than 100uA, which only really works up to about 40k, after that I need a 1uA and 10uA current source to test larger resistor values with 5V

Any recommendations are helpful!
1. Always read the datasheet
2. Never trust the datasheet
 
The following users thanked this post: Marco1971

Offline MrAl

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Re: Current Source for DIY Multimeter
« Reply #1 on: May 15, 2019, 01:24:25 pm »
Hi,

Do a search for "precision current source".
 


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