hi i want to create a flashing LED on a timer

Discussion in 'General Electronics Chat' started by ukash, Jan 22, 2010.

  1. ukash

    Thread Starter New Member

    Jan 22, 2010
    13
    0
    Hi there, basically im rubbish with working out electronics and i need your help, i can build circuits from a diagram, so i need some help creating a circuit which flashes an LED for 5 seconds, 1 flash per second if possible, then stays on permanently, until its switched off, the input will be 12v DC

    thank you
    A
     
  2. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,172
    397
    Two 555s , could be one 556, A & B. A is one-shot, 5 sec , triggered once at power turn on by .1uF holding pin 2 low for fraction of a second. A output ,pin 3 , enables B for 5 sec, pin 4 high.Timing cap B pin 2, should be one uF, giving 1/10 sec flash after 9/10 off, repeats 5 times 'till A resets B; B beeing reset keeps LED on- we hope.
     
  3. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    When you say turned off, how is this supposed to work? Like a flip flop, or removal of power?
     
  4. ukash

    Thread Starter New Member

    Jan 22, 2010
    13
    0
    removal of power
     
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