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    Re: Heath Hezzanith question
    From: Greg R_
    Date: 2007 Oct 22, 21:38 -0700

    --- Chuck Taylor  wrote:
    
    > Bonus question:  What size resistor would I need?
    
    Bonus answer: It's a simple voltage divider/Ohm's Law problem. You'll
    be dropping 1.3 V across the resistor (3.0 - 1.7), and a current of 20
    mA (0.2 A) through the series circuit gives a resistance of 65 ohms if
    I did the math right.
    
    --
    GregR
    
    
    
    > Why not use an LED?  Radio Shack sells a 5 mm red LED for $1.99. It
    > draws 20 ma at 1.7 volts (typical).  My sextant takes two penlight
    > batteries (3 volts). To make this work without smoking the LED, I
    > would need to solder in a resistor of the proper value in order to
    > drop the voltage to 1.7 volts. But first I would have to do the math
    > to compute the proper value for the resistor. I think I'll stick with
    > the red marker. :-)
    >
    > Bonus question:  What size resistor would I need?
    >
    > Cheers,
    > Chuck Taylor
    >   48 N
    > 122 W
    >
    >
    >
    >
    >
    >
    >
    >
    >
    > Gary LaPook writes:
    >
    >
    >
    > Why not use this opportunity to join the 21st century and use a red
    > LED
    > (light emitting diode) cheap at Radio Shack, uses almost no current
    > and
    > lasts forever?
    >
    >
    >
    > gl
    >
    >
    >
    >
    >
    > Chuck Taylor wrote:
    >
    >
    >     red nail polish on the bulb or lens.
    >
    >
    >
    > I use a red felt-tip marker for coloring the bulb on my boat's
    > compass. It works well. It would likely work also on a sextant light.
    >  I picked up that trick from a compass repairman at a boat show.
    >
    > Chuck Taylor
    >   48 N
    > 122 W
    >
    >
    >
    >
    >
    >
    >
    > __________________________________________________
    > Do You Yahoo!?
    > Tired of spam?  Yahoo! Mail has the best spam protection around
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    > >
    >
    
    
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