circuit help

Discussion in 'The Projects Forum' started by kuxz2008, Mar 18, 2010.

  1. kuxz2008

    Thread Starter Member

    Nov 16, 2009
    84
    0
    i have manage to come out with the circuit from a door bell.

    i would like to know what is the IC chip that is being used ....
    and also what type of transistor is used? (NPN/PNP)?
    what is the rectangular thing with a hole (black colour)?
     
    Last edited: Mar 18, 2010
  2. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    The IC is the famous 'Melted Blob' IC. No idea.
     
  3. hondabones

    Active Member

    Sep 29, 2009
    123
    1
    Voltage regulator I would say
     
  4. redlight000

    Member

    Feb 26, 2010
    66
    2
    Hi Kux,
    I dont know if this info will help but might give you some leads.... the Black blob, is called (Chip on board (cob) for short.. its just a chip in there that does the bell ring, as for the Transsistors.. they are I reckon to amplify the sound otherwise it would be to weak to hear..

    Go to www.rapidonline.com then go to semiconductors, then Timers & sig Generators then choose the Ding dong chip!! it also gives a pdf File on how to wire it up..

    Yes Ive wondered about these black blobs.. so I found out some of them hope this helps
    redlight
    :D
     
  5. Bychon

    Member

    Mar 12, 2010
    469
    41
    I have one of those blobs in my bathroom scales. Are you sure this is a door bell?
     
  6. hondabones

    Active Member

    Sep 29, 2009
    123
    1
    I don't think it's an IC. I seen one once that had tiny resistors and such underneath. I think it's more of a way to protect the tiny components from the outside elements or what ever.
     
  7. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    It's a substrate mounted directly on a board, then a blob of black epoxy is placed over it.

    That saves on production costs, and certainly makes it harder to reverse-engineer.

    This thread is not going to go anywhere.
     
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