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Replacing colored LED's

Discussion in 'Archived Threads 2001-2004' started by Jamie, Nov 28, 2002.

  1. Jamie

    Jamie Stunt Coordinator

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    Has anyone replaced the LED's in one's component? For example, what if you had an amplifier with a green LED, and preferred it to be blue instead. Is this a simple changeout, or is it much more involved?

    thanks
     
  2. Jonathan M

    Jonathan M Second Unit

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    Most LED's should be able to be swapped out pretty easily - most use around the same voltage and current, but I guess there is always a small risk that something will go wrong.

    As long as you don't swap any LEDs that are used for determining the bias current of the amplifier etc. it should be OK.

    Let us know if it works. Just make sure you connect the thing the right way around!
     
  3. Dan Pawlowski

    Dan Pawlowski Stunt Coordinator

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    no problem, we're talking milli amps here.
     
  4. Dave Poehlman

    Dave Poehlman Producer

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    Switching from green to blue might be a little more involved. I believe green & red LEDs are driven with less power than blue or white. So, you probably could swap them, however, your blue may not be as bright as your green was.
     
  5. Kevin P

    Kevin P Screenwriter

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  6. Jamie

    Jamie Stunt Coordinator

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    Okay, thanks guys.
     
  7. Paul Stiles

    Paul Stiles Agent

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    There usually is a resistor in series with the led to limit the current flowing through the led. Beings a led is a diode (the "d" in "led"), it, to a first order approximation, tries to keep the voltage across it constant by drawing more or less current as the voltage driving it is changed.

    In your situation, changing from a green to a blue led may give a noticably less light output for two reasons:

    1) The green led drops less voltage than the blue so a series resistor suitable for the green led will have a larger ohms value than a resistor used for a blue led in your particular application.

    2) The human eye is MUCH more sensitive to green light than to blue light.

    To make sure your blue led is putting out enough light to suit you, you will need to make certain that the blue led you have is capable of sufficiently high light output. Early blue leds (and many inexpensive ones available today) could not put out much light.

    In addition, you may need to lower the value of the resistace in series with the led. You can replace the existing resistor or solder another one in parallel with it.

    Paul
     

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