low battery indicator circuit

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this is a very usefull circuit if you're building projects powered by batteries.this simple circuit informs you when the battery needs to be recharged by turning on a led.the threshold is set to the desired voltage by a multiturn potentiometer.
the only thing you should have in mind is that it doesnt work with red led's,at least with the ones i tryied. i think it has something to do with the very low voltage that red led's need to lit.didnt have the time to experiment further.besides that,the circuit works perfect.

components needed:
R1= 1k (2,2k if you use smd led)
R2= 2.2K
U2= TL431 adjustable shunt regulator(can be found very easy in power supplies)
PR1=10K potentiometer (for higher precision use multiturn) 
LED1= led (not red-didnt work with me)


here is a video building it.





Comments

  1. Unknown30 April 2019 at 13:33

    Simple and very useful solution, thanks.

    ReplyDelete
  2. comares electronics28 May 2021 at 03:40

    maybe we can substitute a piezo buzzer for the LED.

    ReplyDelete
  3. comares electronics28 May 2021 at 03:41

    maybe we can substitute led with piezo buzzer.

    ReplyDelete
  4. sss15 July 2021 at 13:29

    hi is it possible to use this circuit for the 12v battery ?

    ReplyDelete
  5. asd11 May 2022 at 13:57

    what is the power consumption of this circuit sir?

    ReplyDelete

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