High voltage LED indicator 40-1000 VDC without additional power supply





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I would like to make an indicator to show that DC bus (700VDC) capacitors are charged (be careful!).



What is the best way to make a LED indicator, which will work for a long time from 40VDC to 1000VDC without additional power supply and with minimum power losses?










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  • $begingroup$
    "work with" how? What is the intention?
    $endgroup$
    – Eugene Sh.
    13 hours ago










  • $begingroup$
    at what? constant current?
    $endgroup$
    – Sunnyskyguy EE75
    13 hours ago










  • $begingroup$
    it should show us that DC bus capacitors are charged
    $endgroup$
    – Nikolay
    13 hours ago






  • 2




    $begingroup$
    Welcome to EE.SE! Keep in mind that questions about optimization (i.e., "What is the best ...?") require a definition about what problem dimensions are to be optimized for your application, such as size, speed, energy consumption, user experience, etc. Since these can't be optimized all at once, you need to have a good idea of which ones are most important to you, and be able to articulate that clearly to us.
    $endgroup$
    – Dave Tweed
    13 hours ago










  • $begingroup$
    ie. you need to supply measureable specs for the LED indicator current and perhaps you want to specify OVP too for 1kV on 700Vdc caps and max. power for this load
    $endgroup$
    – Sunnyskyguy EE75
    13 hours ago




















4












$begingroup$


I would like to make an indicator to show that DC bus (700VDC) capacitors are charged (be careful!).



What is the best way to make a LED indicator, which will work for a long time from 40VDC to 1000VDC without additional power supply and with minimum power losses?










share|improve this question









New contributor




Nikolay is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$












  • $begingroup$
    "work with" how? What is the intention?
    $endgroup$
    – Eugene Sh.
    13 hours ago










  • $begingroup$
    at what? constant current?
    $endgroup$
    – Sunnyskyguy EE75
    13 hours ago










  • $begingroup$
    it should show us that DC bus capacitors are charged
    $endgroup$
    – Nikolay
    13 hours ago






  • 2




    $begingroup$
    Welcome to EE.SE! Keep in mind that questions about optimization (i.e., "What is the best ...?") require a definition about what problem dimensions are to be optimized for your application, such as size, speed, energy consumption, user experience, etc. Since these can't be optimized all at once, you need to have a good idea of which ones are most important to you, and be able to articulate that clearly to us.
    $endgroup$
    – Dave Tweed
    13 hours ago










  • $begingroup$
    ie. you need to supply measureable specs for the LED indicator current and perhaps you want to specify OVP too for 1kV on 700Vdc caps and max. power for this load
    $endgroup$
    – Sunnyskyguy EE75
    13 hours ago
















4












4








4





$begingroup$


I would like to make an indicator to show that DC bus (700VDC) capacitors are charged (be careful!).



What is the best way to make a LED indicator, which will work for a long time from 40VDC to 1000VDC without additional power supply and with minimum power losses?










share|improve this question









New contributor




Nikolay is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$




I would like to make an indicator to show that DC bus (700VDC) capacitors are charged (be careful!).



What is the best way to make a LED indicator, which will work for a long time from 40VDC to 1000VDC without additional power supply and with minimum power losses?







led high-voltage hvdc






share|improve this question









New contributor




Nikolay is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|improve this question









New contributor




Nikolay is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|improve this question




share|improve this question








edited 13 hours ago







Nikolay













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asked 13 hours ago









NikolayNikolay

242




242




New contributor




Nikolay is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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New contributor





Nikolay is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






Nikolay is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.












  • $begingroup$
    "work with" how? What is the intention?
    $endgroup$
    – Eugene Sh.
    13 hours ago










  • $begingroup$
    at what? constant current?
    $endgroup$
    – Sunnyskyguy EE75
    13 hours ago










  • $begingroup$
    it should show us that DC bus capacitors are charged
    $endgroup$
    – Nikolay
    13 hours ago






  • 2




    $begingroup$
    Welcome to EE.SE! Keep in mind that questions about optimization (i.e., "What is the best ...?") require a definition about what problem dimensions are to be optimized for your application, such as size, speed, energy consumption, user experience, etc. Since these can't be optimized all at once, you need to have a good idea of which ones are most important to you, and be able to articulate that clearly to us.
    $endgroup$
    – Dave Tweed
    13 hours ago










  • $begingroup$
    ie. you need to supply measureable specs for the LED indicator current and perhaps you want to specify OVP too for 1kV on 700Vdc caps and max. power for this load
    $endgroup$
    – Sunnyskyguy EE75
    13 hours ago




















  • $begingroup$
    "work with" how? What is the intention?
    $endgroup$
    – Eugene Sh.
    13 hours ago










  • $begingroup$
    at what? constant current?
    $endgroup$
    – Sunnyskyguy EE75
    13 hours ago










  • $begingroup$
    it should show us that DC bus capacitors are charged
    $endgroup$
    – Nikolay
    13 hours ago






  • 2




    $begingroup$
    Welcome to EE.SE! Keep in mind that questions about optimization (i.e., "What is the best ...?") require a definition about what problem dimensions are to be optimized for your application, such as size, speed, energy consumption, user experience, etc. Since these can't be optimized all at once, you need to have a good idea of which ones are most important to you, and be able to articulate that clearly to us.
    $endgroup$
    – Dave Tweed
    13 hours ago










  • $begingroup$
    ie. you need to supply measureable specs for the LED indicator current and perhaps you want to specify OVP too for 1kV on 700Vdc caps and max. power for this load
    $endgroup$
    – Sunnyskyguy EE75
    13 hours ago


















$begingroup$
"work with" how? What is the intention?
$endgroup$
– Eugene Sh.
13 hours ago




$begingroup$
"work with" how? What is the intention?
$endgroup$
– Eugene Sh.
13 hours ago












$begingroup$
at what? constant current?
$endgroup$
– Sunnyskyguy EE75
13 hours ago




$begingroup$
at what? constant current?
$endgroup$
– Sunnyskyguy EE75
13 hours ago












$begingroup$
it should show us that DC bus capacitors are charged
$endgroup$
– Nikolay
13 hours ago




$begingroup$
it should show us that DC bus capacitors are charged
$endgroup$
– Nikolay
13 hours ago




2




2




$begingroup$
Welcome to EE.SE! Keep in mind that questions about optimization (i.e., "What is the best ...?") require a definition about what problem dimensions are to be optimized for your application, such as size, speed, energy consumption, user experience, etc. Since these can't be optimized all at once, you need to have a good idea of which ones are most important to you, and be able to articulate that clearly to us.
$endgroup$
– Dave Tweed
13 hours ago




$begingroup$
Welcome to EE.SE! Keep in mind that questions about optimization (i.e., "What is the best ...?") require a definition about what problem dimensions are to be optimized for your application, such as size, speed, energy consumption, user experience, etc. Since these can't be optimized all at once, you need to have a good idea of which ones are most important to you, and be able to articulate that clearly to us.
$endgroup$
– Dave Tweed
13 hours ago












$begingroup$
ie. you need to supply measureable specs for the LED indicator current and perhaps you want to specify OVP too for 1kV on 700Vdc caps and max. power for this load
$endgroup$
– Sunnyskyguy EE75
13 hours ago






$begingroup$
ie. you need to supply measureable specs for the LED indicator current and perhaps you want to specify OVP too for 1kV on 700Vdc caps and max. power for this load
$endgroup$
– Sunnyskyguy EE75
13 hours ago












4 Answers
4






active

oldest

votes


















6












$begingroup$

Connect a moving coil analog voltmeter across the power bus.



Either a voltmeter as shown with internal series resistor or an external resistor
and scale calibrated for the desired range. Photo from this useless site.



Old-school suppliers such as Crompton should be able to supply a meter with the markings you need, if not a turnkey solution.



enter image description here






share|improve this answer











$endgroup$









  • 1




    $begingroup$
    GMTA .........great alike
    $endgroup$
    – Sunnyskyguy EE75
    12 hours ago



















4












$begingroup$

Something else to consider is to build a relaxation oscillator using a diac, capacitor, LED, couple of resistors.





schematic



Diacs are still readily available, although Digikey wants to sell them in full reels. They can be found at most electronic suppliers as well as places like eBay, aliexpress, banggood, deal extreme.



The advantage of using a relaxation oscillator rather than driving the LED with a large-value resistor is that the LED remains visible (flashing) with low voltages applied. It will stop flashing when the input voltage drops below the sum of the diac trigger voltage and the LED forward voltage,








share|improve this answer









$endgroup$













  • $begingroup$
    Probably the best solution. Only maybe R1 should be 10 M or even more, and the cap under 1uF. Also there are LEDs with 100X light output than the listed one, so R2 can be increased too, which would save power.
    $endgroup$
    – Ale..chenski
    10 hours ago












  • $begingroup$
    I normally use very-high-brightness LEDs. The part number on my schematic is simply what the built-in CAD package has as a default.
    $endgroup$
    – Dwayne Reid
    10 hours ago










  • $begingroup$
    You have to keep the discharge current high enough to ensure that the diac switches cleanly from conducting to not conducting. In other words, R2 has to remain fairly low value. But higher brightness is better anyway.
    $endgroup$
    – Dwayne Reid
    10 hours ago










  • $begingroup$
    Wouldn't using an optocoupler here be preferred to decouple and shift to lower voltage? Signal to user/operator shouldn't be powered by high-voltage if they don't have to.
    $endgroup$
    – Mast
    12 mins ago



















4












$begingroup$

example of a reliable economical no-power-supply (< $10) indicator solution that does not cost > $200 like the other meters. :(



Since this coil draws 50uA full scale it is equivalent to 10V/50uA= 200kOhm. and thus at 1kV the R load is 50 mW full scale with 1kV/50uA = 20MOhm 1% or +/-200kOhm.





schematic





simulate this circuit – Schematic created using CircuitLab



It also draws the least current and is readily available.



enter image description here






share|improve this answer











$endgroup$





















    3












    $begingroup$

    Another potential option is to use a neon bulb or lamp. The common neon indicator that I used to use is the NE-2H - this has fairly-wide current capability and would be able to handle the current range of caused by the supply voltage changing from less than 100V up to 1000V.



    The downside is that a neon indicator does not match your requirement of indicating down to 40 Vdc. The NE-2H extinguishes (after being lit) at about 60 Vdc.



    NE-2 & NE-2H indicators are still readily available. There are also much larger neon bulbs and lamps but they may not be readily available any longer. But you can check.



    Final downside of a neon indicator is that they do die after an extended time. You have to weigh the consequences of the indicator failing some time in the future. Do note that they fail "gracefully" - they don't fail completely at one time, but rather, degrade. You would use that degradation as an indication that the lamp needs to be replaced.






    share|improve this answer









    $endgroup$













    • $begingroup$
      I had considered this but discarded it due to the V range must be <<1mA with 1M series R is barely visible at 50uA , but then when it wears out you can reverse it and use the other electrode to illuminate. ha.
      $endgroup$
      – Sunnyskyguy EE75
      11 hours ago










    • $begingroup$
      I had considered suggesting a simple neon relaxation oscillator but the downside is that the minimum operating voltage would be about 90 Vdc. But it doesn't get much simpler than that - and remains quite visible even with low supply voltage.
      $endgroup$
      – Dwayne Reid
      11 hours ago










    • $begingroup$
      Will the neon work on DC power?
      $endgroup$
      – Harper
      6 hours ago










    • $begingroup$
      Yes. Neon works well on DC supply. However, only one electrode illuminates. Neon relaxation oscillator works only with DC power. But minimum operating voltage for relaxation oscillator is the firing voltage of the neon bulb - about 90 Vdc for NE-2H.
      $endgroup$
      – Dwayne Reid
      6 hours ago












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    4 Answers
    4






    active

    oldest

    votes








    4 Answers
    4






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    6












    $begingroup$

    Connect a moving coil analog voltmeter across the power bus.



    Either a voltmeter as shown with internal series resistor or an external resistor
    and scale calibrated for the desired range. Photo from this useless site.



    Old-school suppliers such as Crompton should be able to supply a meter with the markings you need, if not a turnkey solution.



    enter image description here






    share|improve this answer











    $endgroup$









    • 1




      $begingroup$
      GMTA .........great alike
      $endgroup$
      – Sunnyskyguy EE75
      12 hours ago
















    6












    $begingroup$

    Connect a moving coil analog voltmeter across the power bus.



    Either a voltmeter as shown with internal series resistor or an external resistor
    and scale calibrated for the desired range. Photo from this useless site.



    Old-school suppliers such as Crompton should be able to supply a meter with the markings you need, if not a turnkey solution.



    enter image description here






    share|improve this answer











    $endgroup$









    • 1




      $begingroup$
      GMTA .........great alike
      $endgroup$
      – Sunnyskyguy EE75
      12 hours ago














    6












    6








    6





    $begingroup$

    Connect a moving coil analog voltmeter across the power bus.



    Either a voltmeter as shown with internal series resistor or an external resistor
    and scale calibrated for the desired range. Photo from this useless site.



    Old-school suppliers such as Crompton should be able to supply a meter with the markings you need, if not a turnkey solution.



    enter image description here






    share|improve this answer











    $endgroup$



    Connect a moving coil analog voltmeter across the power bus.



    Either a voltmeter as shown with internal series resistor or an external resistor
    and scale calibrated for the desired range. Photo from this useless site.



    Old-school suppliers such as Crompton should be able to supply a meter with the markings you need, if not a turnkey solution.



    enter image description here







    share|improve this answer














    share|improve this answer



    share|improve this answer








    edited 12 hours ago

























    answered 12 hours ago









    Spehro PefhanySpehro Pefhany

    213k5162429




    213k5162429








    • 1




      $begingroup$
      GMTA .........great alike
      $endgroup$
      – Sunnyskyguy EE75
      12 hours ago














    • 1




      $begingroup$
      GMTA .........great alike
      $endgroup$
      – Sunnyskyguy EE75
      12 hours ago








    1




    1




    $begingroup$
    GMTA .........great alike
    $endgroup$
    – Sunnyskyguy EE75
    12 hours ago




    $begingroup$
    GMTA .........great alike
    $endgroup$
    – Sunnyskyguy EE75
    12 hours ago













    4












    $begingroup$

    Something else to consider is to build a relaxation oscillator using a diac, capacitor, LED, couple of resistors.





    schematic



    Diacs are still readily available, although Digikey wants to sell them in full reels. They can be found at most electronic suppliers as well as places like eBay, aliexpress, banggood, deal extreme.



    The advantage of using a relaxation oscillator rather than driving the LED with a large-value resistor is that the LED remains visible (flashing) with low voltages applied. It will stop flashing when the input voltage drops below the sum of the diac trigger voltage and the LED forward voltage,








    share|improve this answer









    $endgroup$













    • $begingroup$
      Probably the best solution. Only maybe R1 should be 10 M or even more, and the cap under 1uF. Also there are LEDs with 100X light output than the listed one, so R2 can be increased too, which would save power.
      $endgroup$
      – Ale..chenski
      10 hours ago












    • $begingroup$
      I normally use very-high-brightness LEDs. The part number on my schematic is simply what the built-in CAD package has as a default.
      $endgroup$
      – Dwayne Reid
      10 hours ago










    • $begingroup$
      You have to keep the discharge current high enough to ensure that the diac switches cleanly from conducting to not conducting. In other words, R2 has to remain fairly low value. But higher brightness is better anyway.
      $endgroup$
      – Dwayne Reid
      10 hours ago










    • $begingroup$
      Wouldn't using an optocoupler here be preferred to decouple and shift to lower voltage? Signal to user/operator shouldn't be powered by high-voltage if they don't have to.
      $endgroup$
      – Mast
      12 mins ago
















    4












    $begingroup$

    Something else to consider is to build a relaxation oscillator using a diac, capacitor, LED, couple of resistors.





    schematic



    Diacs are still readily available, although Digikey wants to sell them in full reels. They can be found at most electronic suppliers as well as places like eBay, aliexpress, banggood, deal extreme.



    The advantage of using a relaxation oscillator rather than driving the LED with a large-value resistor is that the LED remains visible (flashing) with low voltages applied. It will stop flashing when the input voltage drops below the sum of the diac trigger voltage and the LED forward voltage,








    share|improve this answer









    $endgroup$













    • $begingroup$
      Probably the best solution. Only maybe R1 should be 10 M or even more, and the cap under 1uF. Also there are LEDs with 100X light output than the listed one, so R2 can be increased too, which would save power.
      $endgroup$
      – Ale..chenski
      10 hours ago












    • $begingroup$
      I normally use very-high-brightness LEDs. The part number on my schematic is simply what the built-in CAD package has as a default.
      $endgroup$
      – Dwayne Reid
      10 hours ago










    • $begingroup$
      You have to keep the discharge current high enough to ensure that the diac switches cleanly from conducting to not conducting. In other words, R2 has to remain fairly low value. But higher brightness is better anyway.
      $endgroup$
      – Dwayne Reid
      10 hours ago










    • $begingroup$
      Wouldn't using an optocoupler here be preferred to decouple and shift to lower voltage? Signal to user/operator shouldn't be powered by high-voltage if they don't have to.
      $endgroup$
      – Mast
      12 mins ago














    4












    4








    4





    $begingroup$

    Something else to consider is to build a relaxation oscillator using a diac, capacitor, LED, couple of resistors.





    schematic



    Diacs are still readily available, although Digikey wants to sell them in full reels. They can be found at most electronic suppliers as well as places like eBay, aliexpress, banggood, deal extreme.



    The advantage of using a relaxation oscillator rather than driving the LED with a large-value resistor is that the LED remains visible (flashing) with low voltages applied. It will stop flashing when the input voltage drops below the sum of the diac trigger voltage and the LED forward voltage,








    share|improve this answer









    $endgroup$



    Something else to consider is to build a relaxation oscillator using a diac, capacitor, LED, couple of resistors.





    schematic



    Diacs are still readily available, although Digikey wants to sell them in full reels. They can be found at most electronic suppliers as well as places like eBay, aliexpress, banggood, deal extreme.



    The advantage of using a relaxation oscillator rather than driving the LED with a large-value resistor is that the LED remains visible (flashing) with low voltages applied. It will stop flashing when the input voltage drops below the sum of the diac trigger voltage and the LED forward voltage,









    share|improve this answer












    share|improve this answer



    share|improve this answer










    answered 11 hours ago









    Dwayne ReidDwayne Reid

    18.2k21949




    18.2k21949












    • $begingroup$
      Probably the best solution. Only maybe R1 should be 10 M or even more, and the cap under 1uF. Also there are LEDs with 100X light output than the listed one, so R2 can be increased too, which would save power.
      $endgroup$
      – Ale..chenski
      10 hours ago












    • $begingroup$
      I normally use very-high-brightness LEDs. The part number on my schematic is simply what the built-in CAD package has as a default.
      $endgroup$
      – Dwayne Reid
      10 hours ago










    • $begingroup$
      You have to keep the discharge current high enough to ensure that the diac switches cleanly from conducting to not conducting. In other words, R2 has to remain fairly low value. But higher brightness is better anyway.
      $endgroup$
      – Dwayne Reid
      10 hours ago










    • $begingroup$
      Wouldn't using an optocoupler here be preferred to decouple and shift to lower voltage? Signal to user/operator shouldn't be powered by high-voltage if they don't have to.
      $endgroup$
      – Mast
      12 mins ago


















    • $begingroup$
      Probably the best solution. Only maybe R1 should be 10 M or even more, and the cap under 1uF. Also there are LEDs with 100X light output than the listed one, so R2 can be increased too, which would save power.
      $endgroup$
      – Ale..chenski
      10 hours ago












    • $begingroup$
      I normally use very-high-brightness LEDs. The part number on my schematic is simply what the built-in CAD package has as a default.
      $endgroup$
      – Dwayne Reid
      10 hours ago










    • $begingroup$
      You have to keep the discharge current high enough to ensure that the diac switches cleanly from conducting to not conducting. In other words, R2 has to remain fairly low value. But higher brightness is better anyway.
      $endgroup$
      – Dwayne Reid
      10 hours ago










    • $begingroup$
      Wouldn't using an optocoupler here be preferred to decouple and shift to lower voltage? Signal to user/operator shouldn't be powered by high-voltage if they don't have to.
      $endgroup$
      – Mast
      12 mins ago
















    $begingroup$
    Probably the best solution. Only maybe R1 should be 10 M or even more, and the cap under 1uF. Also there are LEDs with 100X light output than the listed one, so R2 can be increased too, which would save power.
    $endgroup$
    – Ale..chenski
    10 hours ago






    $begingroup$
    Probably the best solution. Only maybe R1 should be 10 M or even more, and the cap under 1uF. Also there are LEDs with 100X light output than the listed one, so R2 can be increased too, which would save power.
    $endgroup$
    – Ale..chenski
    10 hours ago














    $begingroup$
    I normally use very-high-brightness LEDs. The part number on my schematic is simply what the built-in CAD package has as a default.
    $endgroup$
    – Dwayne Reid
    10 hours ago




    $begingroup$
    I normally use very-high-brightness LEDs. The part number on my schematic is simply what the built-in CAD package has as a default.
    $endgroup$
    – Dwayne Reid
    10 hours ago












    $begingroup$
    You have to keep the discharge current high enough to ensure that the diac switches cleanly from conducting to not conducting. In other words, R2 has to remain fairly low value. But higher brightness is better anyway.
    $endgroup$
    – Dwayne Reid
    10 hours ago




    $begingroup$
    You have to keep the discharge current high enough to ensure that the diac switches cleanly from conducting to not conducting. In other words, R2 has to remain fairly low value. But higher brightness is better anyway.
    $endgroup$
    – Dwayne Reid
    10 hours ago












    $begingroup$
    Wouldn't using an optocoupler here be preferred to decouple and shift to lower voltage? Signal to user/operator shouldn't be powered by high-voltage if they don't have to.
    $endgroup$
    – Mast
    12 mins ago




    $begingroup$
    Wouldn't using an optocoupler here be preferred to decouple and shift to lower voltage? Signal to user/operator shouldn't be powered by high-voltage if they don't have to.
    $endgroup$
    – Mast
    12 mins ago











    4












    $begingroup$

    example of a reliable economical no-power-supply (< $10) indicator solution that does not cost > $200 like the other meters. :(



    Since this coil draws 50uA full scale it is equivalent to 10V/50uA= 200kOhm. and thus at 1kV the R load is 50 mW full scale with 1kV/50uA = 20MOhm 1% or +/-200kOhm.





    schematic





    simulate this circuit – Schematic created using CircuitLab



    It also draws the least current and is readily available.



    enter image description here






    share|improve this answer











    $endgroup$


















      4












      $begingroup$

      example of a reliable economical no-power-supply (< $10) indicator solution that does not cost > $200 like the other meters. :(



      Since this coil draws 50uA full scale it is equivalent to 10V/50uA= 200kOhm. and thus at 1kV the R load is 50 mW full scale with 1kV/50uA = 20MOhm 1% or +/-200kOhm.





      schematic





      simulate this circuit – Schematic created using CircuitLab



      It also draws the least current and is readily available.



      enter image description here






      share|improve this answer











      $endgroup$
















        4












        4








        4





        $begingroup$

        example of a reliable economical no-power-supply (< $10) indicator solution that does not cost > $200 like the other meters. :(



        Since this coil draws 50uA full scale it is equivalent to 10V/50uA= 200kOhm. and thus at 1kV the R load is 50 mW full scale with 1kV/50uA = 20MOhm 1% or +/-200kOhm.





        schematic





        simulate this circuit – Schematic created using CircuitLab



        It also draws the least current and is readily available.



        enter image description here






        share|improve this answer











        $endgroup$



        example of a reliable economical no-power-supply (< $10) indicator solution that does not cost > $200 like the other meters. :(



        Since this coil draws 50uA full scale it is equivalent to 10V/50uA= 200kOhm. and thus at 1kV the R load is 50 mW full scale with 1kV/50uA = 20MOhm 1% or +/-200kOhm.





        schematic





        simulate this circuit – Schematic created using CircuitLab



        It also draws the least current and is readily available.



        enter image description here







        share|improve this answer














        share|improve this answer



        share|improve this answer








        edited 10 hours ago

























        answered 10 hours ago









        Sunnyskyguy EE75Sunnyskyguy EE75

        70.7k226103




        70.7k226103























            3












            $begingroup$

            Another potential option is to use a neon bulb or lamp. The common neon indicator that I used to use is the NE-2H - this has fairly-wide current capability and would be able to handle the current range of caused by the supply voltage changing from less than 100V up to 1000V.



            The downside is that a neon indicator does not match your requirement of indicating down to 40 Vdc. The NE-2H extinguishes (after being lit) at about 60 Vdc.



            NE-2 & NE-2H indicators are still readily available. There are also much larger neon bulbs and lamps but they may not be readily available any longer. But you can check.



            Final downside of a neon indicator is that they do die after an extended time. You have to weigh the consequences of the indicator failing some time in the future. Do note that they fail "gracefully" - they don't fail completely at one time, but rather, degrade. You would use that degradation as an indication that the lamp needs to be replaced.






            share|improve this answer









            $endgroup$













            • $begingroup$
              I had considered this but discarded it due to the V range must be <<1mA with 1M series R is barely visible at 50uA , but then when it wears out you can reverse it and use the other electrode to illuminate. ha.
              $endgroup$
              – Sunnyskyguy EE75
              11 hours ago










            • $begingroup$
              I had considered suggesting a simple neon relaxation oscillator but the downside is that the minimum operating voltage would be about 90 Vdc. But it doesn't get much simpler than that - and remains quite visible even with low supply voltage.
              $endgroup$
              – Dwayne Reid
              11 hours ago










            • $begingroup$
              Will the neon work on DC power?
              $endgroup$
              – Harper
              6 hours ago










            • $begingroup$
              Yes. Neon works well on DC supply. However, only one electrode illuminates. Neon relaxation oscillator works only with DC power. But minimum operating voltage for relaxation oscillator is the firing voltage of the neon bulb - about 90 Vdc for NE-2H.
              $endgroup$
              – Dwayne Reid
              6 hours ago
















            3












            $begingroup$

            Another potential option is to use a neon bulb or lamp. The common neon indicator that I used to use is the NE-2H - this has fairly-wide current capability and would be able to handle the current range of caused by the supply voltage changing from less than 100V up to 1000V.



            The downside is that a neon indicator does not match your requirement of indicating down to 40 Vdc. The NE-2H extinguishes (after being lit) at about 60 Vdc.



            NE-2 & NE-2H indicators are still readily available. There are also much larger neon bulbs and lamps but they may not be readily available any longer. But you can check.



            Final downside of a neon indicator is that they do die after an extended time. You have to weigh the consequences of the indicator failing some time in the future. Do note that they fail "gracefully" - they don't fail completely at one time, but rather, degrade. You would use that degradation as an indication that the lamp needs to be replaced.






            share|improve this answer









            $endgroup$













            • $begingroup$
              I had considered this but discarded it due to the V range must be <<1mA with 1M series R is barely visible at 50uA , but then when it wears out you can reverse it and use the other electrode to illuminate. ha.
              $endgroup$
              – Sunnyskyguy EE75
              11 hours ago










            • $begingroup$
              I had considered suggesting a simple neon relaxation oscillator but the downside is that the minimum operating voltage would be about 90 Vdc. But it doesn't get much simpler than that - and remains quite visible even with low supply voltage.
              $endgroup$
              – Dwayne Reid
              11 hours ago










            • $begingroup$
              Will the neon work on DC power?
              $endgroup$
              – Harper
              6 hours ago










            • $begingroup$
              Yes. Neon works well on DC supply. However, only one electrode illuminates. Neon relaxation oscillator works only with DC power. But minimum operating voltage for relaxation oscillator is the firing voltage of the neon bulb - about 90 Vdc for NE-2H.
              $endgroup$
              – Dwayne Reid
              6 hours ago














            3












            3








            3





            $begingroup$

            Another potential option is to use a neon bulb or lamp. The common neon indicator that I used to use is the NE-2H - this has fairly-wide current capability and would be able to handle the current range of caused by the supply voltage changing from less than 100V up to 1000V.



            The downside is that a neon indicator does not match your requirement of indicating down to 40 Vdc. The NE-2H extinguishes (after being lit) at about 60 Vdc.



            NE-2 & NE-2H indicators are still readily available. There are also much larger neon bulbs and lamps but they may not be readily available any longer. But you can check.



            Final downside of a neon indicator is that they do die after an extended time. You have to weigh the consequences of the indicator failing some time in the future. Do note that they fail "gracefully" - they don't fail completely at one time, but rather, degrade. You would use that degradation as an indication that the lamp needs to be replaced.






            share|improve this answer









            $endgroup$



            Another potential option is to use a neon bulb or lamp. The common neon indicator that I used to use is the NE-2H - this has fairly-wide current capability and would be able to handle the current range of caused by the supply voltage changing from less than 100V up to 1000V.



            The downside is that a neon indicator does not match your requirement of indicating down to 40 Vdc. The NE-2H extinguishes (after being lit) at about 60 Vdc.



            NE-2 & NE-2H indicators are still readily available. There are also much larger neon bulbs and lamps but they may not be readily available any longer. But you can check.



            Final downside of a neon indicator is that they do die after an extended time. You have to weigh the consequences of the indicator failing some time in the future. Do note that they fail "gracefully" - they don't fail completely at one time, but rather, degrade. You would use that degradation as an indication that the lamp needs to be replaced.







            share|improve this answer












            share|improve this answer



            share|improve this answer










            answered 11 hours ago









            Dwayne ReidDwayne Reid

            18.2k21949




            18.2k21949












            • $begingroup$
              I had considered this but discarded it due to the V range must be <<1mA with 1M series R is barely visible at 50uA , but then when it wears out you can reverse it and use the other electrode to illuminate. ha.
              $endgroup$
              – Sunnyskyguy EE75
              11 hours ago










            • $begingroup$
              I had considered suggesting a simple neon relaxation oscillator but the downside is that the minimum operating voltage would be about 90 Vdc. But it doesn't get much simpler than that - and remains quite visible even with low supply voltage.
              $endgroup$
              – Dwayne Reid
              11 hours ago










            • $begingroup$
              Will the neon work on DC power?
              $endgroup$
              – Harper
              6 hours ago










            • $begingroup$
              Yes. Neon works well on DC supply. However, only one electrode illuminates. Neon relaxation oscillator works only with DC power. But minimum operating voltage for relaxation oscillator is the firing voltage of the neon bulb - about 90 Vdc for NE-2H.
              $endgroup$
              – Dwayne Reid
              6 hours ago


















            • $begingroup$
              I had considered this but discarded it due to the V range must be <<1mA with 1M series R is barely visible at 50uA , but then when it wears out you can reverse it and use the other electrode to illuminate. ha.
              $endgroup$
              – Sunnyskyguy EE75
              11 hours ago










            • $begingroup$
              I had considered suggesting a simple neon relaxation oscillator but the downside is that the minimum operating voltage would be about 90 Vdc. But it doesn't get much simpler than that - and remains quite visible even with low supply voltage.
              $endgroup$
              – Dwayne Reid
              11 hours ago










            • $begingroup$
              Will the neon work on DC power?
              $endgroup$
              – Harper
              6 hours ago










            • $begingroup$
              Yes. Neon works well on DC supply. However, only one electrode illuminates. Neon relaxation oscillator works only with DC power. But minimum operating voltage for relaxation oscillator is the firing voltage of the neon bulb - about 90 Vdc for NE-2H.
              $endgroup$
              – Dwayne Reid
              6 hours ago
















            $begingroup$
            I had considered this but discarded it due to the V range must be <<1mA with 1M series R is barely visible at 50uA , but then when it wears out you can reverse it and use the other electrode to illuminate. ha.
            $endgroup$
            – Sunnyskyguy EE75
            11 hours ago




            $begingroup$
            I had considered this but discarded it due to the V range must be <<1mA with 1M series R is barely visible at 50uA , but then when it wears out you can reverse it and use the other electrode to illuminate. ha.
            $endgroup$
            – Sunnyskyguy EE75
            11 hours ago












            $begingroup$
            I had considered suggesting a simple neon relaxation oscillator but the downside is that the minimum operating voltage would be about 90 Vdc. But it doesn't get much simpler than that - and remains quite visible even with low supply voltage.
            $endgroup$
            – Dwayne Reid
            11 hours ago




            $begingroup$
            I had considered suggesting a simple neon relaxation oscillator but the downside is that the minimum operating voltage would be about 90 Vdc. But it doesn't get much simpler than that - and remains quite visible even with low supply voltage.
            $endgroup$
            – Dwayne Reid
            11 hours ago












            $begingroup$
            Will the neon work on DC power?
            $endgroup$
            – Harper
            6 hours ago




            $begingroup$
            Will the neon work on DC power?
            $endgroup$
            – Harper
            6 hours ago












            $begingroup$
            Yes. Neon works well on DC supply. However, only one electrode illuminates. Neon relaxation oscillator works only with DC power. But minimum operating voltage for relaxation oscillator is the firing voltage of the neon bulb - about 90 Vdc for NE-2H.
            $endgroup$
            – Dwayne Reid
            6 hours ago




            $begingroup$
            Yes. Neon works well on DC supply. However, only one electrode illuminates. Neon relaxation oscillator works only with DC power. But minimum operating voltage for relaxation oscillator is the firing voltage of the neon bulb - about 90 Vdc for NE-2H.
            $endgroup$
            – Dwayne Reid
            6 hours ago










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