I wonder at what point a topic is to esoteric for here?
Maybe someone that knows more electronics than me can answer. I recently complained about a sodium vapor street light near me that was cycling on and off, as is typical for aging lamps. I happened to see them when they were there, and to my surprise they replaced the twist on photocell as well as the lamp. So do these things go bad? They are socketed, but is that for ease of replacement when they fail, or so they don’t have to have two models of luminere, one with a photocell and one without?
And would a typical failure mean cycling on and off, as opposed to failing either on or off. I’m wondering if they replaced it because it could fail in that matter, on the off chance the cycling was due to the photocontrol and not the bulb, or if they just have a policy of replacing older photocells while they’re at the fixture for any reason, so if it does fail on or off next month they don’t need to make another trip out there.