I tried out op-amp level shifters on web. The ones recomended here as well but there is a problem when no input applied. The output voltage is no seperable from the case voltage applied. As i understand it is called op-amp biasing. I am trying to apply reference voltage with shift voltage but calculation isnt simple. So i am guessing there is a commoon way to do it. How can i sense opamp level shifter has no inputs or how to bias that shifter?
And my biasing idea is like that: