Here Input resistor ladder to step down the voltage. Varistor added to get it away from surge (Fuse included). zener to protect the opto. Opto is darlington with transistor to reduce the opto input current and therefor the input resistor losses.
Since this going to commercial product i would like to gather some info on reliability and surge protection.
1) Is this circuit good enough to handle potential surges/Back emf from inductive loads. 2) Is there any better/cost effective alternatives. 4) I am using 8 in my board to detect 8 channels all are powered from same AC source. Is there a way to consolidate these and reduce overall cost?
Thanks in advance!