This is getting on my nerves....

Discussion in 'General Electronics Chat' started by peck68, Mar 30, 2010.

  1. peck68

    Thread Starter Member

    Nov 27, 2009
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    GRR - this exact circuit was working a week ago, yet I have the urge to make one again today because I managed to find some transistors :)

    Yet, the astable 555 circuit is acting as if it was a monostable circuit - it is only on for a second, then off indefinitely. I have to take out the battery for a few seconds and then connect it again to get the same effect.

    :confused::confused::confused::confused:

    It cant be the timer, since I have two - and must be sheer coincedence that BOTH timers broke. And even then, they couldn't have been broken since it is timing something, but not resetting itself...

    I have built and the rebuilt and then rebuilt the circuit again, the same result ¬_¬

    Attached i have the breadboard of what i am doing - i have tried extending as far as possible to make it clearer for you guys, along with the schematic.

    Apart from that R1 is 10k, R2 is 150k and C1 is 10uF, and its not 1hz - its 0.5 ;)
     
  2. Jony130

    AAC Fanatic!

    Feb 17, 2009
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    Disconnect pin 5 from GND.
     
  3. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Jony130 is right.
    Normaly pin 5 is connected to ground using a capacitor of 10 - 100 nF for decoupling.

    Greetings,
    Bertus
     
  4. Wendy

    Moderator

    Mar 24, 2008
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  5. peck68

    Thread Starter Member

    Nov 27, 2009
    73
    0
    OH yeah that was the one thing i completely forgot about when i did it last time :D

    Thanks a HUGE bundles :) i shall make changes now to that schematic

    ---

    @bill marsden - hmm, why is discharge disconnected? Anyway could be helpful later on

    Thanks all
     
  6. Wendy

    Moderator

    Mar 24, 2008
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    As you get older you will find,

    It is not what you remember, but what you forgot.
     
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