How to keep the state of relay












2














In schematic below when current exceeds the set point of PR1 it toggles the relay and as soon as current drops the relay goes back to normal state:



schematic



How can i keep the relay state as triggered even when the current drops and only switch the relay back to normal state when i pressed a push-button?






relay schematics







share|improve this question




















  • 1




    It would be interesting to hear what this circuit will accomplish once it's done. Some background information is what I'm talking about, who knows, maybe, just maybe, there's a better solution to that than what you've proposed.
    – Harry Svensson
    11 hours ago






  • 1




    Can you use a second relay, or a DPDT relay? Or perhaps some digital logic?
    – mike65535
    11 hours ago










  • thanks @HarrySvensson found the solution.
    – newbie
    9 hours ago










  • thanks @mike65535 found the solution.
    – newbie
    9 hours ago
















2














In schematic below when current exceeds the set point of PR1 it toggles the relay and as soon as current drops the relay goes back to normal state:



schematic



How can i keep the relay state as triggered even when the current drops and only switch the relay back to normal state when i pressed a push-button?






relay schematics







share|improve this question




















  • 1




    It would be interesting to hear what this circuit will accomplish once it's done. Some background information is what I'm talking about, who knows, maybe, just maybe, there's a better solution to that than what you've proposed.
    – Harry Svensson
    11 hours ago






  • 1




    Can you use a second relay, or a DPDT relay? Or perhaps some digital logic?
    – mike65535
    11 hours ago










  • thanks @HarrySvensson found the solution.
    – newbie
    9 hours ago










  • thanks @mike65535 found the solution.
    – newbie
    9 hours ago














2












2








2


1





In schematic below when current exceeds the set point of PR1 it toggles the relay and as soon as current drops the relay goes back to normal state:



schematic



How can i keep the relay state as triggered even when the current drops and only switch the relay back to normal state when i pressed a push-button?






relay schematics







share|improve this question















In schematic below when current exceeds the set point of PR1 it toggles the relay and as soon as current drops the relay goes back to normal state:



schematic



How can i keep the relay state as triggered even when the current drops and only switch the relay back to normal state when i pressed a push-button?






relay schematics




relay schematics






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited 11 hours ago







newbie

















asked 11 hours ago









newbienewbie

419




419








  • 1




    It would be interesting to hear what this circuit will accomplish once it's done. Some background information is what I'm talking about, who knows, maybe, just maybe, there's a better solution to that than what you've proposed.
    – Harry Svensson
    11 hours ago






  • 1




    Can you use a second relay, or a DPDT relay? Or perhaps some digital logic?
    – mike65535
    11 hours ago










  • thanks @HarrySvensson found the solution.
    – newbie
    9 hours ago










  • thanks @mike65535 found the solution.
    – newbie
    9 hours ago














  • 1




    It would be interesting to hear what this circuit will accomplish once it's done. Some background information is what I'm talking about, who knows, maybe, just maybe, there's a better solution to that than what you've proposed.
    – Harry Svensson
    11 hours ago






  • 1




    Can you use a second relay, or a DPDT relay? Or perhaps some digital logic?
    – mike65535
    11 hours ago










  • thanks @HarrySvensson found the solution.
    – newbie
    9 hours ago










  • thanks @mike65535 found the solution.
    – newbie
    9 hours ago








1




1




It would be interesting to hear what this circuit will accomplish once it's done. Some background information is what I'm talking about, who knows, maybe, just maybe, there's a better solution to that than what you've proposed.
– Harry Svensson
11 hours ago




It would be interesting to hear what this circuit will accomplish once it's done. Some background information is what I'm talking about, who knows, maybe, just maybe, there's a better solution to that than what you've proposed.
– Harry Svensson
11 hours ago




1




1




Can you use a second relay, or a DPDT relay? Or perhaps some digital logic?
– mike65535
11 hours ago




Can you use a second relay, or a DPDT relay? Or perhaps some digital logic?
– mike65535
11 hours ago












thanks @HarrySvensson found the solution.
– newbie
9 hours ago




thanks @HarrySvensson found the solution.
– newbie
9 hours ago












thanks @mike65535 found the solution.
– newbie
9 hours ago




thanks @mike65535 found the solution.
– newbie
9 hours ago










3 Answers
3






active

oldest

votes


















7














You can realize the required function using a diode. What needs to be done is to pull one of the inputs of the opamp to such a voltage that the opamp's output stays high (and the relay powered).



Add a diode (1N4148) with the anode to the opamp's output and the kathode to the + input of the opamp. Then when the opamp's output is high (and the relay is powered) the + input of the opamp will be pulled to a higher voltage than R3 and R7 supply (which is about 6 V). The - input of the opamp will not be able to reach that voltage (it will always be at a lower voltage) So the output of the opamp remains high.



To add the reset function, add a 1 kohm resistor in series with the diode and add a switch to ground from the + input to force it low so that the output of the opamp becomes low as well:





schematic





simulate this circuit – Schematic created using CircuitLab






share|improve this answer





















  • A downside of this solution is that it will disarm the relay even in the active area. If it's an overvoltage protection this might be not desirable. Maybe a slight modification could help, using a normal closed push-button in series with D1 instead?
    – Dorian
    10 hours ago










  • Oh, already sugested by Sphero
    – Dorian
    10 hours ago












  • @Dorian A downside of this solution is that it will disarm the relay even in the active area I fail to see how that would happen. Can you explain.
    – Bimpelrekkie
    10 hours ago










  • When you push the switch the relay will be off no matter the input.
    – Dorian
    10 hours ago






  • 1




    @newbie Why do you think you need a 2 A diode? If you do not have the 1N4148 you can use almost any other diode including the 1N4007 that's already in your schematic. Also "tolerance" relates to how accurate something is. Your sentence should have been: ... to tolerate more current up to 2A?. Note that there is a resistor in series with the diode, in this circuit the highest current through the diode is 12V/1kohm = 12 mA which is much less than 2 A.
    – Bimpelrekkie
    8 hours ago



















7














You can add some positive feedback, with a N.C. pushbutton in series.



For example, a diode from the op-amp output to non-inverting input. With said switch in series.



Edit: This is similar to Bimpelrekkie's solution except it requires a N.C. pushbutton, which is less common, and does not force the relay state when the button is pushed. The diode can be any common silicon signal diode such as 1N4148.



Note: If you require a particular guaranteed state at power-up you might have to add some circuitry.



enter image description here






share|improve this answer























  • i'm new to electronics, can you please explain with schematic?
    – newbie
    8 hours ago






  • 2




    Indeed I did not suggest this solution as push-to-open push buttons are hard(er) to find than push-to-close push buttons.
    – Bimpelrekkie
    8 hours ago



















2














If you have a chance to change your relay, you may try to use latching relays.
I'm adding a latching relay below.BTW I couldn't check current and voltage ratings of your circuit. This component is just an example.



https://www.digikey.com/product-detail/en/kemet/EE2-3SNUH-L/399-11008-1-ND/4506460



there is 2 control input in this relay. once you triggered first input and the other one is logic0, relay switches inputs. Until you apply trigger to the second input this will stay same.






share|improve this answer





















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    3 Answers
    3






    active

    oldest

    votes








    3 Answers
    3






    active

    oldest

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    active

    oldest

    votes






    active

    oldest

    votes









    7














    You can realize the required function using a diode. What needs to be done is to pull one of the inputs of the opamp to such a voltage that the opamp's output stays high (and the relay powered).



    Add a diode (1N4148) with the anode to the opamp's output and the kathode to the + input of the opamp. Then when the opamp's output is high (and the relay is powered) the + input of the opamp will be pulled to a higher voltage than R3 and R7 supply (which is about 6 V). The - input of the opamp will not be able to reach that voltage (it will always be at a lower voltage) So the output of the opamp remains high.



    To add the reset function, add a 1 kohm resistor in series with the diode and add a switch to ground from the + input to force it low so that the output of the opamp becomes low as well:





    schematic





    simulate this circuit – Schematic created using CircuitLab






    share|improve this answer





















    • A downside of this solution is that it will disarm the relay even in the active area. If it's an overvoltage protection this might be not desirable. Maybe a slight modification could help, using a normal closed push-button in series with D1 instead?
      – Dorian
      10 hours ago










    • Oh, already sugested by Sphero
      – Dorian
      10 hours ago












    • @Dorian A downside of this solution is that it will disarm the relay even in the active area I fail to see how that would happen. Can you explain.
      – Bimpelrekkie
      10 hours ago










    • When you push the switch the relay will be off no matter the input.
      – Dorian
      10 hours ago






    • 1




      @newbie Why do you think you need a 2 A diode? If you do not have the 1N4148 you can use almost any other diode including the 1N4007 that's already in your schematic. Also "tolerance" relates to how accurate something is. Your sentence should have been: ... to tolerate more current up to 2A?. Note that there is a resistor in series with the diode, in this circuit the highest current through the diode is 12V/1kohm = 12 mA which is much less than 2 A.
      – Bimpelrekkie
      8 hours ago
















    7














    You can realize the required function using a diode. What needs to be done is to pull one of the inputs of the opamp to such a voltage that the opamp's output stays high (and the relay powered).



    Add a diode (1N4148) with the anode to the opamp's output and the kathode to the + input of the opamp. Then when the opamp's output is high (and the relay is powered) the + input of the opamp will be pulled to a higher voltage than R3 and R7 supply (which is about 6 V). The - input of the opamp will not be able to reach that voltage (it will always be at a lower voltage) So the output of the opamp remains high.



    To add the reset function, add a 1 kohm resistor in series with the diode and add a switch to ground from the + input to force it low so that the output of the opamp becomes low as well:





    schematic





    simulate this circuit – Schematic created using CircuitLab






    share|improve this answer





















    • A downside of this solution is that it will disarm the relay even in the active area. If it's an overvoltage protection this might be not desirable. Maybe a slight modification could help, using a normal closed push-button in series with D1 instead?
      – Dorian
      10 hours ago










    • Oh, already sugested by Sphero
      – Dorian
      10 hours ago












    • @Dorian A downside of this solution is that it will disarm the relay even in the active area I fail to see how that would happen. Can you explain.
      – Bimpelrekkie
      10 hours ago










    • When you push the switch the relay will be off no matter the input.
      – Dorian
      10 hours ago






    • 1




      @newbie Why do you think you need a 2 A diode? If you do not have the 1N4148 you can use almost any other diode including the 1N4007 that's already in your schematic. Also "tolerance" relates to how accurate something is. Your sentence should have been: ... to tolerate more current up to 2A?. Note that there is a resistor in series with the diode, in this circuit the highest current through the diode is 12V/1kohm = 12 mA which is much less than 2 A.
      – Bimpelrekkie
      8 hours ago














    7












    7








    7






    You can realize the required function using a diode. What needs to be done is to pull one of the inputs of the opamp to such a voltage that the opamp's output stays high (and the relay powered).



    Add a diode (1N4148) with the anode to the opamp's output and the kathode to the + input of the opamp. Then when the opamp's output is high (and the relay is powered) the + input of the opamp will be pulled to a higher voltage than R3 and R7 supply (which is about 6 V). The - input of the opamp will not be able to reach that voltage (it will always be at a lower voltage) So the output of the opamp remains high.



    To add the reset function, add a 1 kohm resistor in series with the diode and add a switch to ground from the + input to force it low so that the output of the opamp becomes low as well:





    schematic





    simulate this circuit – Schematic created using CircuitLab






    share|improve this answer












    You can realize the required function using a diode. What needs to be done is to pull one of the inputs of the opamp to such a voltage that the opamp's output stays high (and the relay powered).



    Add a diode (1N4148) with the anode to the opamp's output and the kathode to the + input of the opamp. Then when the opamp's output is high (and the relay is powered) the + input of the opamp will be pulled to a higher voltage than R3 and R7 supply (which is about 6 V). The - input of the opamp will not be able to reach that voltage (it will always be at a lower voltage) So the output of the opamp remains high.



    To add the reset function, add a 1 kohm resistor in series with the diode and add a switch to ground from the + input to force it low so that the output of the opamp becomes low as well:





    schematic





    simulate this circuit – Schematic created using CircuitLab







    share|improve this answer












    share|improve this answer



    share|improve this answer










    answered 11 hours ago









    BimpelrekkieBimpelrekkie

    47k240104




    47k240104












    • A downside of this solution is that it will disarm the relay even in the active area. If it's an overvoltage protection this might be not desirable. Maybe a slight modification could help, using a normal closed push-button in series with D1 instead?
      – Dorian
      10 hours ago










    • Oh, already sugested by Sphero
      – Dorian
      10 hours ago












    • @Dorian A downside of this solution is that it will disarm the relay even in the active area I fail to see how that would happen. Can you explain.
      – Bimpelrekkie
      10 hours ago










    • When you push the switch the relay will be off no matter the input.
      – Dorian
      10 hours ago






    • 1




      @newbie Why do you think you need a 2 A diode? If you do not have the 1N4148 you can use almost any other diode including the 1N4007 that's already in your schematic. Also "tolerance" relates to how accurate something is. Your sentence should have been: ... to tolerate more current up to 2A?. Note that there is a resistor in series with the diode, in this circuit the highest current through the diode is 12V/1kohm = 12 mA which is much less than 2 A.
      – Bimpelrekkie
      8 hours ago


















    • A downside of this solution is that it will disarm the relay even in the active area. If it's an overvoltage protection this might be not desirable. Maybe a slight modification could help, using a normal closed push-button in series with D1 instead?
      – Dorian
      10 hours ago










    • Oh, already sugested by Sphero
      – Dorian
      10 hours ago












    • @Dorian A downside of this solution is that it will disarm the relay even in the active area I fail to see how that would happen. Can you explain.
      – Bimpelrekkie
      10 hours ago










    • When you push the switch the relay will be off no matter the input.
      – Dorian
      10 hours ago






    • 1




      @newbie Why do you think you need a 2 A diode? If you do not have the 1N4148 you can use almost any other diode including the 1N4007 that's already in your schematic. Also "tolerance" relates to how accurate something is. Your sentence should have been: ... to tolerate more current up to 2A?. Note that there is a resistor in series with the diode, in this circuit the highest current through the diode is 12V/1kohm = 12 mA which is much less than 2 A.
      – Bimpelrekkie
      8 hours ago
















    A downside of this solution is that it will disarm the relay even in the active area. If it's an overvoltage protection this might be not desirable. Maybe a slight modification could help, using a normal closed push-button in series with D1 instead?
    – Dorian
    10 hours ago




    A downside of this solution is that it will disarm the relay even in the active area. If it's an overvoltage protection this might be not desirable. Maybe a slight modification could help, using a normal closed push-button in series with D1 instead?
    – Dorian
    10 hours ago












    Oh, already sugested by Sphero
    – Dorian
    10 hours ago






    Oh, already sugested by Sphero
    – Dorian
    10 hours ago














    @Dorian A downside of this solution is that it will disarm the relay even in the active area I fail to see how that would happen. Can you explain.
    – Bimpelrekkie
    10 hours ago




    @Dorian A downside of this solution is that it will disarm the relay even in the active area I fail to see how that would happen. Can you explain.
    – Bimpelrekkie
    10 hours ago












    When you push the switch the relay will be off no matter the input.
    – Dorian
    10 hours ago




    When you push the switch the relay will be off no matter the input.
    – Dorian
    10 hours ago




    1




    1




    @newbie Why do you think you need a 2 A diode? If you do not have the 1N4148 you can use almost any other diode including the 1N4007 that's already in your schematic. Also "tolerance" relates to how accurate something is. Your sentence should have been: ... to tolerate more current up to 2A?. Note that there is a resistor in series with the diode, in this circuit the highest current through the diode is 12V/1kohm = 12 mA which is much less than 2 A.
    – Bimpelrekkie
    8 hours ago




    @newbie Why do you think you need a 2 A diode? If you do not have the 1N4148 you can use almost any other diode including the 1N4007 that's already in your schematic. Also "tolerance" relates to how accurate something is. Your sentence should have been: ... to tolerate more current up to 2A?. Note that there is a resistor in series with the diode, in this circuit the highest current through the diode is 12V/1kohm = 12 mA which is much less than 2 A.
    – Bimpelrekkie
    8 hours ago













    7














    You can add some positive feedback, with a N.C. pushbutton in series.



    For example, a diode from the op-amp output to non-inverting input. With said switch in series.



    Edit: This is similar to Bimpelrekkie's solution except it requires a N.C. pushbutton, which is less common, and does not force the relay state when the button is pushed. The diode can be any common silicon signal diode such as 1N4148.



    Note: If you require a particular guaranteed state at power-up you might have to add some circuitry.



    enter image description here






    share|improve this answer























    • i'm new to electronics, can you please explain with schematic?
      – newbie
      8 hours ago






    • 2




      Indeed I did not suggest this solution as push-to-open push buttons are hard(er) to find than push-to-close push buttons.
      – Bimpelrekkie
      8 hours ago
















    7














    You can add some positive feedback, with a N.C. pushbutton in series.



    For example, a diode from the op-amp output to non-inverting input. With said switch in series.



    Edit: This is similar to Bimpelrekkie's solution except it requires a N.C. pushbutton, which is less common, and does not force the relay state when the button is pushed. The diode can be any common silicon signal diode such as 1N4148.



    Note: If you require a particular guaranteed state at power-up you might have to add some circuitry.



    enter image description here






    share|improve this answer























    • i'm new to electronics, can you please explain with schematic?
      – newbie
      8 hours ago






    • 2




      Indeed I did not suggest this solution as push-to-open push buttons are hard(er) to find than push-to-close push buttons.
      – Bimpelrekkie
      8 hours ago














    7












    7








    7






    You can add some positive feedback, with a N.C. pushbutton in series.



    For example, a diode from the op-amp output to non-inverting input. With said switch in series.



    Edit: This is similar to Bimpelrekkie's solution except it requires a N.C. pushbutton, which is less common, and does not force the relay state when the button is pushed. The diode can be any common silicon signal diode such as 1N4148.



    Note: If you require a particular guaranteed state at power-up you might have to add some circuitry.



    enter image description here






    share|improve this answer














    You can add some positive feedback, with a N.C. pushbutton in series.



    For example, a diode from the op-amp output to non-inverting input. With said switch in series.



    Edit: This is similar to Bimpelrekkie's solution except it requires a N.C. pushbutton, which is less common, and does not force the relay state when the button is pushed. The diode can be any common silicon signal diode such as 1N4148.



    Note: If you require a particular guaranteed state at power-up you might have to add some circuitry.



    enter image description here







    share|improve this answer














    share|improve this answer



    share|improve this answer








    edited 8 hours ago

























    answered 11 hours ago









    Spehro PefhanySpehro Pefhany

    204k4150408




    204k4150408












    • i'm new to electronics, can you please explain with schematic?
      – newbie
      8 hours ago






    • 2




      Indeed I did not suggest this solution as push-to-open push buttons are hard(er) to find than push-to-close push buttons.
      – Bimpelrekkie
      8 hours ago


















    • i'm new to electronics, can you please explain with schematic?
      – newbie
      8 hours ago






    • 2




      Indeed I did not suggest this solution as push-to-open push buttons are hard(er) to find than push-to-close push buttons.
      – Bimpelrekkie
      8 hours ago
















    i'm new to electronics, can you please explain with schematic?
    – newbie
    8 hours ago




    i'm new to electronics, can you please explain with schematic?
    – newbie
    8 hours ago




    2




    2




    Indeed I did not suggest this solution as push-to-open push buttons are hard(er) to find than push-to-close push buttons.
    – Bimpelrekkie
    8 hours ago




    Indeed I did not suggest this solution as push-to-open push buttons are hard(er) to find than push-to-close push buttons.
    – Bimpelrekkie
    8 hours ago











    2














    If you have a chance to change your relay, you may try to use latching relays.
    I'm adding a latching relay below.BTW I couldn't check current and voltage ratings of your circuit. This component is just an example.



    https://www.digikey.com/product-detail/en/kemet/EE2-3SNUH-L/399-11008-1-ND/4506460



    there is 2 control input in this relay. once you triggered first input and the other one is logic0, relay switches inputs. Until you apply trigger to the second input this will stay same.






    share|improve this answer


























      2














      If you have a chance to change your relay, you may try to use latching relays.
      I'm adding a latching relay below.BTW I couldn't check current and voltage ratings of your circuit. This component is just an example.



      https://www.digikey.com/product-detail/en/kemet/EE2-3SNUH-L/399-11008-1-ND/4506460



      there is 2 control input in this relay. once you triggered first input and the other one is logic0, relay switches inputs. Until you apply trigger to the second input this will stay same.






      share|improve this answer
























        2












        2








        2






        If you have a chance to change your relay, you may try to use latching relays.
        I'm adding a latching relay below.BTW I couldn't check current and voltage ratings of your circuit. This component is just an example.



        https://www.digikey.com/product-detail/en/kemet/EE2-3SNUH-L/399-11008-1-ND/4506460



        there is 2 control input in this relay. once you triggered first input and the other one is logic0, relay switches inputs. Until you apply trigger to the second input this will stay same.






        share|improve this answer












        If you have a chance to change your relay, you may try to use latching relays.
        I'm adding a latching relay below.BTW I couldn't check current and voltage ratings of your circuit. This component is just an example.



        https://www.digikey.com/product-detail/en/kemet/EE2-3SNUH-L/399-11008-1-ND/4506460



        there is 2 control input in this relay. once you triggered first input and the other one is logic0, relay switches inputs. Until you apply trigger to the second input this will stay same.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered 10 hours ago









        KorayKoray

        503




        503






























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