I need some help with IC 555 Timer Diagram

Discussion in 'The Projects Forum' started by Dalefhome, Jan 9, 2014.

  1. Dalefhome

    Thread Starter New Member

    Jan 9, 2014
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    Hi to All
    I have a 555 timer kit that is adjustable from 1 to 15 min. I need the timer to
    repeat the timing cycle contentiously until the stop button is pushed.
    If I connect pin 2 to pin 6 will that do what I need. Please look at the attachment diagram. If it is not as simple as connecting pin 2 to pin 6, Please
    give me a step by step.
    Thank you All
     
  2. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    What is the Velleman part number?
     
  3. SgtWookie

    Expert

    Jul 17, 2007
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  4. Dalefhome

    Thread Starter New Member

    Jan 9, 2014
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    Velleman-Kit K2579RS Universal Start/Stop Timer
     
  5. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    The K2579 is an example of the 555 in a monostable configuration (also called a one-shot.) The operation that I think you want is astable operation, and the Vellman MK111 is designed for that. Both schematics are attached for comparison.

    I don't know all the steps that would be required to convert the K2579 to astable operation. Maybe someone else can supply that information.

    The K2579 needs a negative-going pulse on pin 2 of the 555 in order to trigger it. You could do that by creating an external circuit that simply oscillated between +V and ground at the speed you want the relay to operate, and connecting that output to pin 2 of the 555.

    The simplest way to get what you want is to buy an MK111, or to build your own 555 astable multivibrator.
     
  6. Dalefhome

    Thread Starter New Member

    Jan 9, 2014
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    Thank you for replying
    I need the time cycle to be 15min. The K2579 max 1 min.
    I hope someone can tell me how to modify the K2579
     
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