High & low voltage sensor

I was thinking of building a high and low voltage protector for household appliances but im not sure about the part that ectaully detect whether there is high or low voltage going to an appliance

You would use a comparator circuit. However, there would be a need for signal conditioning of the AC mains voltage. The comparator would be a "Window Comparator" with preset high and low limits.

Ron

Why do you think you need one?

i have made some research about the high/low voltage cut-off with time delay and the one i saw it uses two 741 op-amp as comparators as to detect the high and low voltage but my question is, will it okay or economical if i use a dual LM393 instead of two 741 op-amp?or it will just complicate the whole circuit

This is a very good link about comparator circuits. Yes, the LM393 would be a better choice as it is designed as a comparator unlike the old 741 operational amplifier. The link shows Window Comparator designs. Keep in mind the LM393 is an open collector design.

Ron

RELOADRON im having problem with the computer that im using i can only see this part of your response text "(This is a very good link about comparator circuits. Yes, the LM393 would be a better choice as it is designed as a comparator unlike the old 741 operational amplifier. The link shows Window... )" when i try to click on it as to see the whole message it's loading forever. Can you plz just post the comparator link again. just the link, as im only seeing only the first part of the text. I appreciate your help,thank you.

This is the link. You are not having a problem with your computer. That was a My Bad.

Ron