Here's a post using a zener diode which has a very similar function to a 2-pin precision voltage reference except the PVR is more stable and accurate. In a later post someone mentions a PVR instead, I will admit I hadn't checked typical minimum currents for PVR's however your source isn't short of current, choosing a resistor to draw at least 1mA isn't going to be a problem,.If you use a 6V voltage reference to subtract then your 8.4V and 7V will vary between 2.4V and 1V on the ADC, it won't go below 0V with lesser voltages on the input.What happens if the voltage to be measured is greater than 3.3v?
It might pay to put a high value resistor (eg 100k) between ADC input and ground to ensure there is a bit of current flow for the precision reference.
Could you tell me more about this? I've been researching it, but I'm not very familiar with voltage references. They seem simple and inexpensive, but I can't tell how to use them to subtract voltage. I'm not sure what the schematic would look like for this, and searching anything to do with reference voltages with respect to an ADC just talks about reference voltages for ADC.
https://www.eevblog.com/forum/beginners ... msg3581145
Statistics: Posted by pidd — Fri Jan 26, 2024 4:47 am