Use of Optocoupler 4N49 in our circuit is as switch as shown in the attached diagram.
As per the datasheet, IF=2mA can give Ic upto 2mA (CTR=100% in Saturation Region). Does it include degradation over 10 or 15 years of Life and temperature variations?
What will be optimal combination of IF and Ic by considering degration over 15 years of operation and temperature variation from -25 degrees Celsius to +60 degrees Celsius for optocoupler to work as a switch?