I am using an ncd relay power switch that is capable of reading 8 sensors.
When I use the 5V and GND provided by the board I get a Vo=3.46V. If i switch R1 to 100k I actually get Vo= 2.7.
When i use an external 5V and GND provided by a power supply I get Vo=2.6, still using R1=10k here.
Question: Why am I getting different voltage values from the two different power sources. Why am I having to switch R1 to 100k to get the proper Vo when using the relay board? Is there some voltage reference I need to take into account?
According to curstomer support "the ADC inputs on that board float(they are not pulled either direction".