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Discussion in 'Electronic Design' started by James Cranfield, Aug 1, 2006.

  1. Hello,

    I sincerely apologise for the phenomenally newbie question but here goes....


    I have an ISD1730 chip which essentially plays a sound thru a speaker whenever one of the pins drops low, it has an internal pull up resistor.
    How can I use a non-physical switch to trip it? Basically I would like to have an Astable circuit trip it. How can I do this? Can I just put the output of an Astable onto it; or would I have to put a NOT gate in between so it is always high then goes low on the high pulse from the astable???

    Please help



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  2. Donald

    Donald Guest

    Need a little more information.

    If your npot using a "switch", what are you using ??

    An opto-isolator would work if I know what was controlling the opto.

    Help me, help you !
     
  3. mc

    mc Guest

    I have an ISD1730 chip which essentially plays a sound thru a speaker
    The latter, I think.
     
  4. John Fields

    John Fields Guest

    ---
    You could use an astable with complementary outputs and drive the
    1730 with the negative-true output, or if you wanted to use
    something like a 555/7555 you could do this: (View in Courier)

    IDS
    1730
    +----+
    |_ |
    +---O|E |
    | | |
    C +----+
    ASTABLE OUT>---[1KR]---B 2N3904
    E
    |
    GND
     
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