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  1. S

    Please help me with High Low voltage cutoff with time delay

    Will any one of the below work... If both works..which is better and why..If not pls. show me how to do it. Please let me know.  thanks
  2. S

    Please help me with High Low voltage cutoff with time delay

    OK, Now I figured out. By connecting both the output of the window comparator You are creating an OR function...as both output got open collector type of output. It must work ..as it is the logical thing... Sorry..I now connected the +ve connection of inverter U1C TO +5vdc..it was connected...
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    Please help me with High Low voltage cutoff with time delay

    I know what u are saying... And thank you for your help, this is the first ever complete circuit i hv ever drawn. Well they were tied together.  You hv r5 = 100k, I hv got two r5's (r7 & r8 of my circuit) with two 100k registors.  I hv separated them only because I hv added two LEDs their...
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    Please help me with High Low voltage cutoff with time delay

    Hi, I'hv just corrected your r6 and r7..switched the registors 100k and 330k... hv no change in behavior.. Also tried again connecting your U1C "+" connection to the r3 & r4 devider...delay to deactivating relay for the low side went longer about 30s. High side of the window comparator...
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    Please help me with High Low voltage cutoff with time delay

    hello, I did not find any mistakes other then, Your circuits U1C is connected to 5vdc instead of the R3 & R4 divider...this is done as per your post, "U1C is just a logic inverter, the + input could be connected to Vref rather than R3 and R4,..." Your circuits R5 for U1B is a preset...
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    Please help me with High Low voltage cutoff with time delay

    OK, Did solved the low side problem. Changed r1 to 15k and as soon as below 2.45 vdc relay turns off... But for high side window comparator lights up at 5.10~5.20 vdc but relay do not turn off. Can Anyone please help solve this problem. Do I need separate transistor to turn relay off for...
  7. S

    Please help me with High Low voltage cutoff with time delay

    After lots of struggle and work...managed to get the circuit complete. Here the comparator U2A and U2B works just fine. At around R2=5.05 vdc, high side LED turns on but relay does not operate.  But If I get this to over 12.5 vdc relay turns off..not sure why. At around R2 = 3.10 vdc low side...
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    Please help me with High Low voltage cutoff with time delay

    thank you... OK, u can help me no problem hehe... Your info. is invaluable... thanks again... ;D
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    Please help me with High Low voltage cutoff with time delay

    This is the window comparator..., If I use a TL431 Voltage regulator then shall get 100ma as per it's datasheet., Pls. don't laugh..this is the first time I'm drawing in a schematic drawing soft. I shall hv to learn more..,
  10. S

    Please help me with High Low voltage cutoff with time delay

    Hello hero, Thanks and appreciate your response. First I must say..You are the man..as from your reply I can guess you are an expert in this side of the terrirory..though this kinds of situation may not be the case in your country. Also, I'm not very keen to this circuit things...(I did built...
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    Please help me with High Low voltage cutoff with time delay

    hello hero999, Thank you for your reply. As I hv mentioned before my power line voltage 230vac at 50 Hz What my plan was to build a small unregulated power supply that can feed the circuit and can monitor real time ac voltage. My No cutoff zone is  : 170 vac ~ 270 vac. Any voltage above or...
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    Please help me with High Low voltage cutoff with time delay

    Hi herman, I did searched, I hv found more with some 555 and some with all transistor. This one looked more logical then them.  If you hv found some much better can you post back the link/URL. thanks
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    Please help me with High Low voltage cutoff with time delay

    I hv forgot to mention, I have also got some quad comparators HA17339, which I believe are equivalent to LM339.  hOPE can someone help me in this regard... Here is the scemetic of the protector circuit..,
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    Please help me with High Low voltage cutoff with time delay

    Hi, Power line fluctuation is very common in my country, so was looking to build a Hi/low cutoff circuit for my power inverter which do not have one. I hv found this circuit that looks nice, http://www.free-circuits.com/circuits/power-supplies/221/high-and-low-voltage-cut-off-with-time-delay...
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