I’m having trouble understanding why the following circuit uses the inverting configuration rather than the non-inverting configuration for amplification.
This design is from the Sparkfun Current Sensor Breakout (Low Current version): Sparkfun Low Current Sensor Breakout
I do not understand why it can be said that the gain is +2x to +22x. Shouldn’t this be -2x to -22x gain since it is an inverting op amp configuration. A = -R1/R2 ?
After doing some reading, the only reasoning I can come up with is the fact that the input impedance in the inverting config is much lower and thus would affect the sensor measurement much less than in a non-inverting config.
I do not understand how this inverted output is going directly to an ADC pin in their hookup guide found here: Hookup Guide for Current Sensor Breakout Does the ADC only care about the absolute value?
It is not re-inverted again in firmware either. I think I am missing something extremely trivial and it’s bothering me a lot. Also, in my intended application, I would eliminate the trimpot on the positive input of the op amp and have a direct reference to ground, since I am only interested in sensing positive direct current that my application will consume from a wall adapter.