12V sense.... remote turn on???

Discussion in 'General Electronics Chat' started by theeld, Feb 24, 2007.

  1. theeld

    Thread Starter Member

    Oct 5, 2006
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    I am on a design team that is developing some new hardware. Ideally we would like our device to be powered when an 12V switched power signal is sensed. The signal that we are recieving is not capable of driving our board/system itself. We are powering from a seperate 12V source. Essentially we want a voltage controlled Master Switch that is automatically switched on when the 12V switched power signal is present in place of a physical toggle switch or something. Obviously this sounds like a transistor or MOSFET, but there will be significant current flowing through the switch for long periods of time and am not sure if a transistor will survive over time. Any suggestions?

    THEELD
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    Everything is a guess without some parameters, such as: voltage, current and nature of the signal.
     
  3. tek_fool

    New Member

    Feb 24, 2007
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    Well in my feild we use Solid State Relays,,sory I am just new to them myself and I am also switching a source remotely, however I am actually havning a little trouble witht he current wiring.
    The device I am using it a Data logger that has a programable 12 volt switch channel,(it will switch on for a time period when a certain condition is true),this is preprogrammed into the logger and communication (sms alarm message on event ) takes place over a SAM (Stand alone modem).
    It really depends on when/how you want it switched (remotely, on event,when condition is true,timed).

    cheers
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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    Actually, it depends on how you want it switched. I am merely trying to be helpful.
     
  5. tek_fool

    New Member

    Feb 24, 2007
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    ..........
     
  6. mrmeval

    Distinguished Member

    Jun 30, 2006
    833
    2
    Do both circuits have to be isolated from each other? What is the max current allowed to be drawn from the monitored voltage? Can this be a switch closure? Did you want the DC supply to the circuit to be turned on (not powered) by the monitored 12V?
     
  7. theeld

    Thread Starter Member

    Oct 5, 2006
    12
    0
    The sensed 12V is not powering the board only switching the power to the board provided by a seperate DC power source. I am estimating current consumption to be at a max of 8-10 amps continuous for a period of 2-3 minutes and 1 amp 95% of the time.
     
  8. theeld

    Thread Starter Member

    Oct 5, 2006
    12
    0
    bump......
     
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