555 -how to solve?

Discussion in 'General Electronics Chat' started by bama, Nov 26, 2008.

  1. bama

    Thread Starter New Member

    Nov 21, 2008
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    I have cascaded 4 555 ics in monostable. ie, the first Ic will be given a momentary trigger, then it will be driving a led which glows for 3 seconds. Then it has to trigger the second 555. Where the timings are set such that the IInd led glows for 50 secs. Next it will be used to trigger the third 555. Then the led connected with the iiird 555 glows for 10 second./ Last one glows for 20 seconds. I tested tyhe circuit individually. It works fine. But if cscaded it is not working. The ist led alone is glowing for the set time. rest are just idle. What is wrong?
    Pls help to find out. I need a 555 IC tester circuit also.
     
  2. Wendy

    Moderator

    Mar 24, 2008
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    We'll need a schematic to even begin to help with your issue. You can compare your schematic to this experiment and compare as a starting point.

    We really do need your schematic to be able to help.

    This was the wrong place to post this, you need to use the Electronic Projects forum in the future. This forum is to allow feedback and suggestions for the online All About Circuits Book, a good read I highly recommend.

    I recommend this experiment for the tester.
     
    Last edited: Nov 26, 2008
  3. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    A schematic is needed. However, I suspect you need to use a capacitor to couple the two stages. John
     
  4. Wendy

    Moderator

    Mar 24, 2008
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    Early bird or night owl? Time for bed for me. G'nite.
     
  5. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Earlier bird.

    I have been wrestling with an EAGLE problem to pass DRC and couldn't sleep. John
     
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