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Question about circuit

Discussion in 'Electronic Basics' started by ahonda55, Oct 25, 2005.

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  1. ahonda55

    ahonda55 Guest

  2. Here is the data sheet for the chip:
    http://www.emesystems.com/pdfs/parts/LM2907.pdf

    Read page 7.

    There are a couple ways to increase the output by a factor of 2. You
    could double the size of the timing capacitor, C1, or you could double
    the value of the load resistor, R1. Or you could change both values
    such that their product is twice the listed values for C1 and R1.
     
  3. ahonda55

    ahonda55 Guest

    Thank you very muc
    I did that already , but i need to increase the (sensetivity) of th
    tachomete
    for example, at 2000 RPM 1v , at 4000 RPM it should be 2v , i want t
    make it 3v or more

    i will try to reduce the (ref. high) in the LED driver IC LM3914,
    think it may work

    if it worked i wil post the result here

    Thanx a lo
     
  4. ehsjr

    ehsjr Guest


    From the datasheet John mentioned:
    Vout = Vcc * Fin * R1 * C1 * K
    (K generally equals 1)
    Try changing C1 from 47 nF to 100 nF and see if that gives you
    what you want.

    Ed
     
  5. ahonda55

    ahonda55 Guest

    i will do that and see if it works

    i dunno how to thank you Ed :) and all of you :
     
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