After awhile, optocouplers get old and their Current Transfer Ratio becomes smaller meaning that the amount of current able to pass through the collector decreases for the same current put in to the emitter.
How can one figure out what the forward current on the emitter should be for the longest optocoupler life but still be able to turn on the transistor enough after aging and the CTR decreases?
Let's use the FODM124 as an example. Here's the datasheet
How can one figure out what the forward current on the emitter should be for the longest optocoupler life but still be able to turn on the transistor enough after aging and the CTR decreases?
Let's use the FODM124 as an example. Here's the datasheet