Re: hi.in ADI Water Analysis Solution for pH Meters.pdf there is a block in the name of programmable ac current in conductivity meter . i can not understand why there is not a single current source for that

thanks alot it is absolutely right . i have used ad8626 opamp in my circuit and i got wrong current from +vref and when use -vref.the other task i want to have 1ua current with this circuit . i wanna know your opinion about using r3 about 2 Mohm is this this value correct for this circuit?