cksimkoza4 The translation to English for me might not be working correctly. What you have described is what I call "A horrible case of the 'Normals'". The circuit is responding exactly as it is designed to do. The system response is triggered / activated by light - not mains power.
By the way I'm new to electronics, but initially the sensor used to behave normaly such that when its during the day the security lights are off due to the increase in light intensity, and when it becomes dark(night) security lights turn on automatically. It operates like this when there is power from the mains the whole day, but now when power goes off at night (blackout) and comes back on, the security lights remain turned off, but initially when we justed installed the photocell it used to automatically turn on the security lights even after blackout
By the way I'm new to electronics, but initially the sensor used to behave normaly such that when its during the day the security lights are off due to the increase in light intensity, and when it becomes dark(night) security lights turn on automatically. It operates like this when there is power from the mains the whole day, but now when power goes off at night (blackout) and comes back on, the security lights remain turned off, but initially when we justed installed the photocell it used to automatically turn on the security lights even after blackout
maybe lighting conditions during the night has changed? let's suppose that this sensor has three states "definitely day", "intermediate state" and "definitely night", and in "intermediate state" it's behavior depends on previous state. In this case, when some times ago night was darker than now, it correctly interpreted it every time as "definitely night", but now it is fitting into "intermediate state", which is working correctly when it "sees" difference from day to this "intermediate state" but not when it powers-up in this state? Maybe there is some sensitivity potentiometer that can be tuned (after remembering current position for easy return if it doesn't work)?
cksimkoza4 Thank you. I understand much better now. I do not have a solution. I do have occupancy sensors that behave similarly when the returning mains power is from my battery inverter. They only reset when powered by utility power. This validates JWx's suggestion that it could be an edge triggering issue - at least in my mind. If you were able to reset the mains power to the circuit after the lights failed to come back on, do they behave correctly? Power quality is terrible as mains power returns - with everything trying to restart.
The other crazy idea is if your photosensor has analog potentiometers. Sometimes these items get oxidized. Note the position of the pointer. Turn left, right, left right, and back to the original position. While simple, I have corrected many sensing problems this way.
