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how to pulse a signal

Former Member

I want to build a hack that closes a switch using an optocoupler every 1-100 times a second. I was wondering what module/circuit/ic that could pulse an adjustable signal using a pot. Could someone direct me in what could do that?

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    Hi Kyle,

     

    That is often done with a '555' ic circuit, see here for examples (and consult the datasheets and google for timing formulas).

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    Nothing wrong with a 555.  Some of the people who use them exclusively seem like moped-ridin' script-kiddies to me.  I should have better discretion then to vent my prejudices here, but I am on my first cuppa.  Since I am having a hemorrhage of opinion, let me throw in that shabaz is a more-than-competent electronics designer, and provides practical and appropriate advice.  Let me show you an alternative with generic parts:

     

    image

    Yes, you are reading the screed of someone who draws schematics with a crayon.

     

    Where did you get a switch capable of 100Hz?  Is it a mercury wetted relay?

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    I'm dating myself.  When the 555 surpassed the 741 in sales, the community saw this as a milestone and were aghast.

     

    I can recall three resolutions among the serious hipster design community.

     

    1)  Have a novel application or three for the 555 in your design portfolio.

    2)  Never use a circuit from the 555 datasheet.

    3)  Include an op-amp on every board, regardless.

     

    Actually the guys who designed the 555 were great, clever guys and the 555 was one of the great design kills of history.  I just wish they would have pinned-out more nodes.

     

    Interestingly, a third party figured out how to get it to oscillate 50/50 after it was released.  The guys who designed the chip didn't figure that out before it was launched upon the market.