Bit of help on the LM3914/LM3915 Please

Discussion in 'General Electronics Chat' started by Supra man, Apr 8, 2005.

  1. Supra man

    Thread Starter New Member

    Apr 8, 2005
    3
    0
    hi and hello to everyone...

    i am after some help with a couple of circuits i want to make, first off i would like to make a bar graph circuit so that all the LEDs light up at a certain resistance from a water temp sensor, then as its gets warmer for the lights to go out one by one on different tempretures, do i need a LM3914 or LM3915 or LM3916? does anyone have a circuit for this or very similar please??

    Also i would like to make a circuit for a tacho from a car, need a frequency to voltage convertor which will then go through one of the LM ICs (which one?) again anyone have a circuit for this?

    thanks
     
  2. mozikluv

    AAC Fanatic!

    Jan 22, 2004
    1,437
    1
    hi

    you can use the suggested circuits of National for your purpose. am also attaching 2 circuits not of my making but from another author. :D

    oops sorry i forgot to include the circuit, here it is. :rolleyes:
     
  3. Supra man

    Thread Starter New Member

    Apr 8, 2005
    3
    0
    hi

    thanks for that, i can only see one pic, so will the input on this circuit work for an adjustable resistance source ie from the temp sender unit and a voltage source from the tacho source?
     
  4. mozikluv

    AAC Fanatic!

    Jan 22, 2004
    1,437
    1
    hi

    yes it can accept variable sources and if you intend to use LCDs as your display you use the 3915 or 3914, but if you like to use LCD use the 3916.

    sorry for the other pic, i don't know what happend maybe i forgot. anyway here it is with some explanation. :D
     
  5. Supra man

    Thread Starter New Member

    Apr 8, 2005
    3
    0
    thats great, thanks a lot..
     
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