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Thermocouple Applications to generate current to run a very small led ?

  1. Dec 11, 2014 #1
    Can I use a thermocouple which has a temperature difference of 1 degree to generate current to run a very small led.
     
  2. jcsd
  3. Dec 11, 2014 #2

    mfb

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    If you find some way to have a huge heat flow and if you can increase the voltage by orders of magnitude: maybe. In practice, probably not. LEDs need a minimal voltage (depending on the color, but at least ~2V) to work.
     
  4. Dec 12, 2014 #3

    dlgoff

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    Here's a graph showing the Millivolts produced at various temperatures for several common Thermocouple types. Not much change in voltage per ºC change in temperature.

    480px-Intermediate_temperature_thermocouples_reference_functions.svg.png
     
  5. Dec 12, 2014 #4
    When I was a kid, there was a project in an encyclopedia that used a series of thermocouples to power a small radio. By
    wiring thermocouples in series, you get what's termed a thermopile.
    The design I read about used a lamp socket and candle along with a bunch of thermocouples.
    Later I learned that Russians often used a similar arrangement to power radios.
     
  6. Dec 12, 2014 #5

    jim hardy

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  7. Dec 12, 2014 #6
    Yes, LOL, you'll need a zillion thermocouples to make it from 1 degree C or F.
    Piltier devices (used for 12 volt coolers) offer a simple means of getting voltage from a temperature difference.
    I've applied 12 volts to one, allowed it to settle, and then used it to power a small 6v bulb for a short time. Fun!
     
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