Need help

Discussion in 'The Projects Forum' started by what66, Jul 21, 2010.

  1. what66

    Thread Starter New Member

    Jul 21, 2010
    Hello guys I need some help with a circuit I'm building.
    I build it and it work for a few mins and then the chip gets hot and it dies.
    I have built it 4 times and it does it every time I'm using a 12v power supply and using it to switch a transistor.
    I'm using a cd4001ube chip any help would be great I need this for my big project It's really making me mad. :mad:
    Thanks all.
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    You have a quad OR gate. With any logic IC, but CMOS in particular, all unused inputs must be tied to ground or Vcc to prevent uncontrolled oscillations that will wreck the chip. You can just connect all 6 of the unused inputs to ground.
  3. what66

    Thread Starter New Member

    Jul 21, 2010
    Well I did what you said I also did some research that confirmed what you told me.
    But it still fry's the chips I guess I need to find a different circuit.:mad:
    Anyone know any good timing circuits I need one that goes for 5 sec's
    All it has to switch is a transistor any help would be great thanks.
  4. windoze killa

    AAC Fanatic!

    Feb 23, 2006
    Firstly, are you absolutely sure you have wired it correctly?

    Secondly, you could try using a 555 timer to switch the transistor.
  5. Wendy


    Mar 24, 2008
    Are you sure D2 is in there correctly? It is to absorb a high voltage spike generated by the coil of the relay when current is abruptly discontinued. D2 keeps the circuit intact if this happens. D3 is not needed, it does nothing. R3 could also be eliminated.
  6. what66

    Thread Starter New Member

    Jul 21, 2010
    Thanks for your help guys But I give up on this circuit.
    I already got a replacement it has a 555 timer and switches a transistor.
    I tested it on the bread board and it works:).
    So thanks for your help all also if anyone knows a circuit that can detect current flow and turn on a relay I could use it thanks.