how to determine operating temperature of diode ?

Discussion in 'Homework Help' started by abhimanyu143, Jun 2, 2015.

  1. abhimanyu143

    Thread Starter Member

    Aug 25, 2014
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    Hello
    how to determine the temperature of diode during working condition ?
    1. diode
    2. capacitor
    3.regulator Ic
    4. resistor
    5. LED
    6. battery

    I have connected all component on breadboard
    upload_2015-6-3_4-51-30.png
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Learn how to post a schematic diagram
     
  3. Jony130

    AAC Fanatic!

    Feb 17, 2009
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    In diode datasheet try to find a Thermal resistance between junction to ambient (Rthja).
    Next find diode forward current If and diode forward voltage drop Vf and find the power dissipation in the diode Ptot = If * VF. And finally find diode junction temperature Tj = Tambient + Rthja*Ptot.
     
  4. abhimanyu143

    Thread Starter Member

    Aug 25, 2014
    211
    1
    upload_2015-6-3_8-25-3.png
     
  5. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    What does the upright triangle symbol represent? A power supply?
    Are you expecting that temperature effects D1, and somehow that is going to effect the voltage output of the regulator?

    Hint: Even if the diode had an effect on the voltage at pin 1 of the regulator, the regulator is specifically designed to ignore voltage fluctuations at its input, so what are you trying to accomplish?
     
  6. Jony130

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    Feb 17, 2009
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    Yes, this is normal for Proteus vsm.
     
  7. MikeML

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    Oct 2, 2009
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    And what is the voltage?
     
  8. abhimanyu143

    Thread Starter Member

    Aug 25, 2014
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    I am using 9 v dc battery. actually I am trying to do some analysis my self by doing some practicals step by steps
     
  9. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    The diode where it is will help protect you if you plug the battery in backwards, which is quite easy to do with a 9V battery.

    Mike gave you the start of figuring out (well, estimating) the temperature of the diode. Don't forget the 7805 will waste some current (typically called quiescent current) that never makes it to the load so there are two sources of current out of the diode: load and regulator.
     
  10. wmodavis

    Well-Known Member

    Oct 23, 2010
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    Learn to read and understand the manufacturers data sheet. That is what it is for - to help you understand the component and use it properly so it will have a long and happy life.
     
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