battery voltage level indicator

Discussion in 'The Projects Forum' started by Parth Goda, Jan 10, 2012.

  1. Parth Goda

    Thread Starter New Member

    Jan 4, 2012
    hey guys i am new to electronics n i hav been trying to make a voltage level indicator for these specifications
    red led on when battery voltage below 3v
    red led blink at 1hz when battery level 6v>x>5.6v
    green led on when voltage >10v
    orange led on when voltage 10.5>x>6v
    i am trying without any ICs but ony using LM431

    any advice appreciated
  2. mcasale

    Active Member

    Jul 18, 2011
    This sounds pretty simple - assuming you have a DC supply other than your battery - and you use some ICs in the design. Not sure why you decided on the LM431without knowing your circuit.

    I recommend using something like an LM339 quad comparator. It can run off of a single supply and has an open-collector output, which might be able to drive a low-current LED directly. The offset voltage should be okay for this.

    I also recommend putting some hysteresis (positive feedback) on each comparator so it does not oscillate around the switch point.

    The 1Hz blinking can be done with a 555 timer chip.

    If you don't understand this advice, I recommend you start Googling these topics.

    Good luck!
  3. russpatterson

    Senior Member

    Feb 1, 2010
    What kind of battery functions at less than 3V and greater than 10V?
  4. praondevou

    AAC Fanatic!

    Jul 9, 2011
    Ok, the voltage comparator part can easily be done with 431s. I have however never seen an oscillator build around a 431. Don't know if this is possible. As was mentioned the oscillator part is easiest being done with a 555.
  5. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    Use a flashing LED for the output that needs to flash, or does the flash need to be performed by the circuit?
  6. PaulEE


    Dec 23, 2011
    Perhaps they're using a super-cap and calling it a battery?
  7. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    Then the LEDs will use half the available power