You need an hysteresis based comparator - one that changes state (OFF) when voltage falls below 180 V and then changes state again (ON) when the voltage rises above 191 V. I believe you can use a simple op-amp comparator with hysteresis - only you need to scale the input voltage by a factor of 100 (180 V becomes 1.8 V and 191 V becomes 1.91V) to remain within the op-amp's specs.
I am a little concerned that you profess to have little knowledge on the subject, and are working with lethal voltages, I would strongly suggest that you enlist direct help from someone who is used to working with such voltages, and that your work is looked over before commissioning to ensure it is safe, cheers, Richard
I do have knowledge about ac line, I have a running POD with 5 minutes delay and that cuts off at 180 volt, I just can't get to activate it at exact 191 volt. my circuits activates at 185 volt, I've tried changing my zener diode but I still cannot get the desired 191 volt activation.
The discussion focuses on designing a power-on delay (POD) circuit that cuts off power below 180 V and activates above 191 V with a 5-minute delay, intended for air conditioning and refrigeration applications. A recommended approach involves using a comparator with hysteresis to create voltage thresholds with a 180 V cutoff and 191 V activation, achieved by scaling the input voltage to within op-amp specifications. One solution suggests employing a 555 timer IC combined with additional components: zener diodes to establish the 180 V reference, a voltage divider to scale the voltage difference (11 V between 180 V and 191 V) down to a suitable level, and configuring the 555 timer pins 2 and 6 to detect threshold voltage changes. The 555 timer output acts as a switch, and a separate 555 timer circuit implements the 5-minute delay. Challenges include precise activation at 191 V, with attempts to adjust zener diodes not yielding exact results. Safety concerns are raised due to working with high AC voltages, recommending professional oversight. The discussion highlights the need for a schematic diagram for clarity and practical implementation. Summary generated by the language model.
