I'm trying to design a Analog to Digital Converter circuit with a OPAMP circuit helps convert Vin from bipolar to unipolar signal before goes to input ADC pin (just look at the circuit!)
well the circuit works so far, but when the Vin = GND, I can't get the Vout from OPAMP = GND (0V). it just higher! So how to solve this? I tried using LM358, LM393, LM324, MCP6002, but it still not worked =( Please help Here are some of my ideas i think might work but i don't know how to build: - Switch to another OPAMP. i think good OPAMP might help but i don't know what type, and the price will be a problem because i don't have so much money - Are there any ways to subtract the Vout from OPAMP? like VinADC = VoutOPAMP - Vsubtract, then it can get to 0V. but I didn't found anything seem possible! - I tried researching the Virtual Ground methods, so I think there are some how make the ground of the ADC circuit "higher" than the OPAMP circuit ground, but still supply enough current for the ADC and following circuits (at least 50mA). Any suggestions? Please help!! And by the way sorry if my English is not good =)) thanks!