Hey guys,
I am working with a pressure sensor with a strain gauge arranged in a Wheatstone Bridge. I have a two-parter question.
1. Why does the sensor performs better with voltage excitation vs current excitation, for a temperature test over -40°C to 80°C?
With this question, I want to get some understanding of our findings.
We are getting approximately 1.166 %error/°C when we are using 0.5mA current source across the sensor. There is a 3V voltage drop across the sensor.
Whereas if we use say 2.5V voltage excitation we get 0.233 %error/°C. Of course, the absolute error of the current/voltage source doesn't account for the difference in error
Intuitively I would think a higher voltage across the sensor will yield better stable readings, irrespective of how it is generated (voltage/current excited). We also tested the sensor with a higher voltage of 4V but there were diminishing returns, we just got 0.2166 %error/°C.
2. The Second question I have is about the configuration shown in the image below
Here the main advantage is that this configuration doesn't need a stable reference source. What I want to know is apart from not needing a precision voltage reference is there any added advantage for such a configuration?