1. Getting desired threshold voltage 2. Delay in the output of 555 IC

[sdmuashr]

How can I vary/set desired threshold voltage in 555 IC using potentiometer?
How can I get delay in the output of 555 IC?

Note: I want to use 555 IC in bistable mode (as an alternative of Schmitt trigger) and I want to apply sine wave as input to 555 IC.