Low current tilt switch to power LED?

Discussion in 'General Electronics Chat' started by Mshadow, Jun 3, 2008.

  1. Mshadow

    Thread Starter New Member

    Jun 3, 2008
    5
    0
    I am trying to use a particular tilt switch which only has 1ma out to control an LED. How would you use a 2N7000 transistor or other gate component to allow the real current 20ma to pass to the LED and not cook the tilt switch? Here is the dsheet:
    http://www.components.omron.com/components/web/PDFLIB.nsf/0/F8EBDDB7A51A229C8625730D0076401A/$file/D6BN_0307.pdf.

    Battery is 3.7v Also, no matter what solution is found it needs to be very small.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    The link gives me an error. The question is why a switch can only output 1 mill? Switches usually have contacts capable of more current than that. I suppose this is some kind on contained device? Even without that limitation, you will need to be able to place 10 volts on the 2N7000's gate to switch it.
     
  3. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    Use a BC108 transistor to drive your led.
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Beenthere,
    Problem with the link is the period at the end.
    This worked for me:
    http://www.components.omron.com/components/web/PDFLIB.nsf/0/F8EBDDB7A51A229C8625730D0076401A/$file/D6BN_0307.pdf

    mik3,
    That's it? :rolleyes:

    Mshadow,
    The switch is not only limited in current, it's limited in voltage as well. If you get it much over 3.5v @1mA, you'll fry it.

    You'll need to limit the voltage across it, as well as the current through it. Not something I can answer in 5 minutes, which is all the time I can spend on it at the moment.
     
  5. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    I thought this is obvious from the datasheet.

    But Mshadow, you can use a 3.3 Volts voltage regulator like the LM2937 or one you can find easily to drive your switch.Also you can use the same regulator to power your led.
     
    Last edited: Jun 3, 2008
  6. Mshadow

    Thread Starter New Member

    Jun 3, 2008
    5
    0
    Mik3 et al,

    Sorry for the pathetically basic question here. Thank you for all of the responses, especially Mik3 and the voltage regulator solution.

    Mshadow
     
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