latch circuit

Discussion in 'General Electronics Chat' started by fred_uk, Feb 11, 2009.

  1. fred_uk

    Thread Starter Active Member

    Jan 3, 2009
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  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    It's one method of making a latching circuit. What are you latching? Why are you latching it?
     
  3. fred_uk

    Thread Starter Active Member

    Jan 3, 2009
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    it goes to a digital input on a gsm modem that needs to be held high until it is reset using the reset input. battery consumption is also an important factor. i like the circuit listed because it has a reset and alarm led, i would like to use a bi coloured led, flashing say once every 30 seconds green if reset and red every 30 seconds of in 'alarm' condition.

    thanks
    fred
     
  4. mik3

    Senior Member

    Feb 4, 2008
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    Use a RS latch IC of the CMOS technology to reduce power consumption. CMOS consume less power when used in low frequency applications compared to TTL.
     
  5. fred_uk

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    Jan 3, 2009
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    would the same ciruit be suitable with a different ic?
     
  6. mik3

    Senior Member

    Feb 4, 2008
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    Yes, if the ic has the same function.
     
  7. bertus

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  8. fred_uk

    Thread Starter Active Member

    Jan 3, 2009
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    is that like a potential divider... bit new to this...sorry!
     
  9. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Normal TTL (74XX) and HCT (74HCTXX) will work from 4.75 to 5.25 Volts.
    Cmos (40XX) will work from 3 to 15 Volts.
    HC mos (74HCXX or 40HCXX) will work from 3 to 6 Volts.

    Greetings,
    Bertus
     
  10. fred_uk

    Thread Starter Active Member

    Jan 3, 2009
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    looks like i need to contact the manufactures and confirm what the inputs are and their ratings!
     
  11. bertus

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