Adjustable delay switching of two relays alternately

Discussion in 'General Electronics Chat' started by adjeiwaf, Mar 4, 2015.

  1. adjeiwaf

    Thread Starter New Member

    Mar 4, 2015
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    I need to alternately switch two dry contacts /relays with variable time delays say 15mins or 20mins intervals .Think a 555 timer would work but will it be adjustable and have these two outputs?
     
  2. #12

    Expert

    Nov 30, 2010
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    One timer chip can not count both 15 minutes and 20 minutes at the same time. It will be adjustable if you build it to be adjustable. A 555 timer is really stretching to do 20 minutes. Better try a CD4020 counter chip.
     
  3. adjeiwaf

    Thread Starter New Member

    Mar 4, 2015
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    kindly help e with cd 4020typicadiagram l
     
  4. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Start by downloading and reading the 4020 data sheet. It will likely have all you need to proceed.
     
  5. Reloadron

    Active Member

    Jan 15, 2015
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    You can as mentioned build your own circuit around a CD4020 timer chip and a Google of CD4020 Timer Circuits will yield dozens of circuits or as Mike mentioned, work from the data sheet. If this is for a commercial or industrial application another option is to simply buy a timer relay and a Google of Timer Relays will also bring up dozens of solutions which are plug and play. Since I have no clue as to your location I can't suggest manufacturers or model numbers of plug and play solutions.

    Ron
     
  6. #12

    Expert

    Nov 30, 2010
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    I was designing circuits before the Internet was invented. I had to read the datasheet and teach myself how to connect chips. I assumed everybody did that. AmIright?
     
  7. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    No just old :p

    Sadly.. The datasheet is usually the last thing people look at now a days..
    Way too many forums/tutorials/youtube videos/blog posts,etc.. about EVERYTHING...
     
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  8. #12

    Expert

    Nov 30, 2010
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    Let me clarify: Before the internet was invented, did everybody have to read the datasheet and teach themselves how to connect IC's?
     
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  9. Reloadron

    Active Member

    Jan 15, 2015
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    Before the Internet was invented I had to find the data sheet. If the data sheet wasn't in the department library then I took a walk to the main company library. The real bitch was before the copy machine was available.

    Ron
     
  10. #12

    Expert

    Nov 30, 2010
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    OMG! I couldn't live like that!
    I have to go back to the datasheet a dozen times during a design.
     
  11. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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  12. Reloadron

    Active Member

    Jan 15, 2015
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  13. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Before the Internet, I got the Texas Instruments TTL Data Book... And The CMOS Cookbook...
     
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