How does the power supply of a smoke detector work ?

Discussion in 'General Electronics Chat' started by Roger at CCCC, Oct 6, 2015.

  1. marcf

    Member

    Dec 29, 2014
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    43
    My smoke detector 'loads' the 9v battery every 1 min with about 0.1ma for about 1 sec. as measured with my Fluke DVM as long as the 120 AC voltage is present. If the battery is present there is no chip, if the battery is low or not present, the detector chips.

    I suspect there is probably a UL or NFPA rule about supervising the battery.
     
  2. WBahn

    Moderator

    Mar 31, 2012
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    7,611
    What, exactly, is your question? The thread title and the contents of the post seem virtually unrelated.
     
  3. marcf

    Member

    Dec 29, 2014
    250
    43
    Excuse me, but I thought we were discussing how smoke detectors are powered. There was also some discussion about actually measuring the power consumption of one. Sorry.
     
  4. InspectorGadget

    Active Member

    Nov 5, 2010
    212
    42
    Yes, we were. Thank you, Mike. That was an important data point; an observed monitoring of the battery by an AC powered smoke detector. The point being it does access the battery, but it seems only to monitor it, not to be powered by it.

    Very relevant, Mr. Moderator.
     
  5. WBahn

    Moderator

    Mar 31, 2012
    24,356
    7,611
    I messed up and thought that this was a new thread and that the top post above (Post #21) was the initial post in the thread. I didn't realize that the link took me to the second page.
     
    InspectorGadget likes this.
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