Background and inspiration for this project came from Jim Teixeira article published in Nuts Volt magazine, https://www.nutsvolts.com/magazine/article/build-a-variable-voltage-reference
Here is my attempt to build this tool along with some performance measurements. The main difference is that I have added the power LED as well as USB power cable to directly connect to a USB 2.0 port. But there is future enhancements that can be added to make it even more versatile.
- Current version have negative output due to inverting op amp configuration. I want to use a modified REF102C circuit to give -10V precision output (Figure 2 below from REF102C datasheet)
- Replace REF102C to REF5010 for reference IC as it has higher accuracy with very low temperature drift.
- Use this tool to get a ADC linearity of Arduino ADC.
Here is what my fixture internal looks like:
Here are my measured values as Jim showed. I get very comparable results to his measurements, which make sense as I pretty much follow the same components and board placement.
In future, I plan to replace the reference chip to REF5010 as well as add some ADC linearity measurement for my Arduino. Please subscribe if you are interested in to see this project progress. In conclusion this is good tool to have in any electronic lab.