ADC - Single Ended vs Differential

txaggie

Hello all,

I am trying to set up a circuit with my bs2px to interact with my software I wrote. I don't really have any background in EE, just enough to fry some transistors occasionally. I have a question about ADC's and the difference between single ended and differential. I am currently using an ADC0834 with 5V as the reference and two AAA batteries as the voltage I am trying to read. With single-ended, when I have the negative lead tied to digital ground and the positive lead to channel 0, I get about 2.56 VDC, which is pretty close. If I leave the positive on channel 0 and change the negative to channel 1 and change the mux addressing accordingly, I get 1.59 VDC. I am hoping someone can give me some clarity on why this is. I was under the impression that differential readings, measures the potential between the negative channel and the positive channel. Is there something more that I need to take into consideration when calculating this (ie the Vref)?

Thanks,
Scott

Phil Pilgrim (PhiPi)

Channel 1 and channel 2 are not a differential pair. You have to use 0/1 or 2/3.

-Phil

txaggie

Thanks Phil. I apologize. In my first post, I was referring to channel 0 and channel 1 or mux address %100 for differential. I have it hooked up correctly, I just referred to the channels incorrectly in my post.

Thanks,
Scott

txaggie

Does anyone know what could be wrong with my setup?

Thanks,
Scott