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RELAY TESTER

Discussion in 'Electronic Design' started by [email protected], Mar 10, 2007.

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  1. Guest

    I NEED TO DESIGN A TESTER TO CHECK 2 DIFF. STYLE RELAYS. I HAV
    DESIGNED ON THAT WORKS WITH ONE L.E.D. TO SHOW IF THE SWITCH CLOSES
    ON THE RELAY, BUT I WOULD LIKE TO USE A DUAL (REE-GRN.) POLARITY
    L.E.D..
    IF THE SWITCH CLOSES THE GRN. LED LIGHTS, IF IT DOESN'T THE THE RED
    LED SHOULD LIGHT. I'M NOT SURE HOW TO USE THIS TYPE OF LED.
    THANKS, ME
     
  2. Tim Wescott

    Tim Wescott Guest

    Step one:

    Drive current through in one direction to make it light red, drive
    current through in the other direction to make it light green.

    Step two:

    Note that while the red/green difference may be perfectly apparent to
    you, the most common form of color blindness is red/green, and pure
    colors like LED's are the most likely to be indistinguishable to someone
    with the disability. So you're making a tester that will automatically
    not work for 8 to 12 percent of the male population. Worse, folks with
    this disability have learned that if you peer carefully at the LED you
    can tell which chip is on by it's position -- which means they may not
    say they're color blind, they may just pass a bunch of bad relays for
    you to use.

    http://webdesign.about.com/od/accessibility/a/aa062804.htm

    Note that to me, the "red green red green" graphic on the right side is
    _all the same color_.

    Step three:

    Throw away those dammed colored lights, an use something that _I_ can use!

    --

    Tim Wescott
    Wescott Design Services
    http://www.wescottdesign.com

    Posting from Google? See http://cfaj.freeshell.org/google/

    "Applied Control Theory for Embedded Systems" came out in April.
    See details at http://www.wescottdesign.com/actfes/actfes.html
     
  3. John B

    John B Guest

    STEP 0 - FIND THE CAPS LOCK KEY AND PRESS IT.
     
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