I'm trying to use an H11AA1 (datasheet) optocoupler to test when my doorbell is pressed (I'm in an apartment building):
It worked when I first tested it, but then it stopped working less than a day later. I have a second optocoupler (which I bought with the idea that I would almost certainly break the first one somehow), and if I swap it in it works. The input part is supposedly rated for 230VAC, so I don't think the issue is there.
I've disconnected it all for now out of fear of breaking the second optocoupler. What did I do wrong?