555 timer queries

Discussion in 'The Projects Forum' started by alagiri123, Jun 30, 2008.

  1. alagiri123

    Thread Starter New Member

    Jun 30, 2008
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    I needed a DC motor to be running for particular duration. I wired a 555timer. The 555 was made to power a relay so that the relay would make/break the supply to motor.

    I faced the following problem

    I observed that once the timer is triggered, the 555 goes to ON state but doesn't return back to low state even after the RC duration. When I connected the relay as a 'Normally ON' load (Pin3 to relay and the other end of the relay to V+), the circuit works!

    Can somebody help in reasoning this pls?
     
  2. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    368
    Do you have a schematic ?
     
  3. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    More important, do you have a protection diode across the relay coil? If not you could be damaging the 555. The previous poster is also correct though, we need a schematic to be of any real assistance.
     
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