Over and under AC voltage protect circuit

[Javier]

Hi all. in the place where I live, the main electric line AC level (110VAC) is not constant; sometimes the AC voltage is over 110VAC but it can also be under that level for example at 90 or less. This AC variations can affect my home appliances, specially my freezer which is old but still useful for me. I know I should buy an AC voltage protector but I would like to build my own protect circuit (I enjoy DIY devices). The only idea coming to my mind is a circuit based on a voltage comparator with LM339 or LM324 wired as "Ventana" ( in spanish maybe translated into English window) comparator monitoring an input voltage taken from main AC line compared to a fixed reference voltage. If you have any schematic concerning to this kind of circuit, I will thank you, any idea or suggestion. Thank you. Regards. Javier

 

[ramussons]

Google is a excellent option.

http://www.eleccircuit.com/over-voltage-and-low-voltage-protection-circuit/


https://www.google.co.in/search?q=ac+overvoltage+undervoltage+schematic

 

[Bluejets]

Go and see your local supply authority or local electrician. That range of voltage swing means something is not right.

 

[Javier]

hi guys; thank you for replying me; I wanted one showing through LEDs the state of the AC level: Two red Leds indicating Very low voltaje and other low voltage; Yellow indicating waiting time (I think so) and green led normal operation and other led with any different colour to determine overvoltage; Excuse me, I think I am being dull with my request; I have a protect device against under and overvoltage but it works on 220V therefore I have to calculate some resistors and caps to make it work on 110V.
Blue, there is a big problem with the company supplying the electrical service; The problem is so serious that the regional government and the energy ministery will put end to the company because of its bad service; this is the hard reality of this country. God bless you