555 timer

Discussion in 'General Electronics Chat' started by mindgame2, Jan 30, 2009.

  1. mindgame2

    Thread Starter Member

    Jan 24, 2009
    12
    0
    i want to use 555 timmer i have gone through its data sheet
    i am a little messed up with adjusting the resistors and capacitors value to get the desired frequency
    if any one could plz send me the formula to determine the frequency which would be produced by the timmer
    also circuits diagrams would be helpful for me
     
  2. veritas

    Active Member

    Feb 7, 2008
    167
    0
    time = RC
    therefore,
    freq = 1/(RC)

    I don't have the data sheet handy, so I can't give more specifics right now, but that's the basis of it.
     
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    For astable operation, the timing formula is:

    f = 1.44/(Ra + 2 Rb) C

    The data sheet has all the timing nomograms in it.
     
  4. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    The information you seek is contained in the datasheet for the device.

    hgmjr
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    There are lots of tutorials on the Web.
    Google "555 tutorial" and you'll have lots of hits.

    Schematica's 555 Timer Lite is freeware, and can be downloaded here:
    http://www.schematica.com/555_Timer_design/555_Timer_PRO.htm
    It doesn't have all the functionality of 555 Timer Pro, but you can use it indefinitely in the freeware mode.
     
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