Turn motor on for 5 seconds

Discussion in 'The Projects Forum' started by Yeezus, Jun 10, 2014.

  1. Yeezus

    Thread Starter New Member

    May 13, 2014
    11
    1
    I have a simple project which is to turn a 12v motor on after I press a pushbutton. I made the circuit work with an led, but when I replace the led with a motor circuit with transistor, the circuit stops working.
     
  2. Yeezus

    Thread Starter New Member

    May 13, 2014
    11
    1
    Nevermind I found my problem.
     
  3. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    2,809
    834
    What behavior do you observe? That is, what are the details of how it stops working.

    Some observations of my own. There is no base resistor on the transistor. You need one to limit current and prevent magic smoke from occurring. This may be your problem.

    Secondly, your push button is not debounced. Hence, each press will result in multiple clock inputs to the flip flop. It may not end in the desired state.

    Also, I suspect that there is an unused NOR gate. It should have its inputs tied to ground and it's output left disconnected.
     
  4. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    2,809
    834
    What was it?
     
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