I tested those photocontrols today (not that I was expecting to find dayburning photocontrols in the box LOL), and interestingly the four Fisher-Pierce are magnetic and instant response! The black photocontrol is electronic and quick-response.
Of course....I tested them first.....and yeah, you may also notice each PC has slightly different "personalities" too.....some maganetic ones may make noises at a low level light also........and for the maganetic ones, during a thunderstorm....a lightning will momentarly shut off the light (and if its MV or MH they will hot restrike...and the HPS will act like if they cycled!)
Actually, they buzz at HIGH light levels! In complete darkness they're silent. As I raise the light level going into the eye, the relay buzzes more and more until it clicks off!
Interestingly I've seen thermal photocontrols turning off with a lightning strike. It recently happened with a GE M250A2 in front of my house during the biggest thunderstorm we had in 7 years! There was like one lightning strike every 3 seconds!
Thermal Photocells are more fun...and actually have lower failure rates.....it seems newer electronics fails more...and shorter life....
But I have noticed high failure rates of 1994 Fisher Peirce Thermal Photocells, cuz I have gotten like 6 or 7 1994 photocells and like about 4 of them or so wouldn't work at all, not even dayburning...just complete off nothing...one was a dayburner and one 1994 photocell worked....
I have a lot of thermal photocells from 1960s throughout 2000 and a lot of those from 1960s, 1970s, and the 80s working just fine, some is dayburning, and others not too sensitive....but the rest...works GREAT!
But electronic don't go off if there is a lightning strike or headlights shine at them, that is better for the light and is safer, plus most places replace the PCs every relamping.
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I guess the discoloured one is the oldest then?
Just click on the pic and look closely you will see the dates on the top
Interestingly I've seen thermal photocontrols turning off with a lightning strike. It recently happened with a GE M250A2 in front of my house during the biggest thunderstorm we had in 7 years! There was like one lightning strike every 3 seconds!
But I have noticed high failure rates of 1994 Fisher Peirce Thermal Photocells, cuz I have gotten like 6 or 7 1994 photocells and like about 4 of them or so wouldn't work at all, not even dayburning...just complete off nothing...one was a dayburner and one 1994 photocell worked....
I have a lot of thermal photocells from 1960s throughout 2000 and a lot of those from 1960s, 1970s, and the 80s working just fine, some is dayburning, and others not too sensitive....but the rest...works GREAT!