Don't try this at home - a blue LED connected directly to a 9v battery without a current limiting resistor burns out quickly - it could easily explode so watch out. But you can connect a blue, white or UV LED directly to a CR2032 lithium coin cell safely as a quick LED self test. If you look inside those cheap LED keyring torches, this is exactly how it's done.

By Julian

Youtuber, shed dweller, solar charge controller aficionado

14 thoughts on “Blue led dies rapidly on 9v battery but ok on cr2032 lithium coin cell”
  1. Avataaar/Circle Created with python_avatars JEYAPAL JAYARAMAN says:

    Excellent

  2. Avataaar/Circle Created with python_avatars Silvia Colombi says:

    good video thanks. 
    Is there a way to connect a botton battery with a switch control(on/off) and a led?

  3. Avataaar/Circle Created with python_avatars Funkyboodah says:

    9v seems overkill for the small led, no?

  4. Avataaar/Circle Created with python_avatars TAPAN KUMAR Banerjee says:

    👍

  5. Avataaar/Circle Created with python_avatars Sean Smith says:

    Next up: clock radio dies rapidly at 1 kV but OK on 240 V AC.

  6. Avataaar/Circle Created with python_avatars Edwin says:

    This video is old. (this comment written June22.2018) Is it possible to make a wire less/hidden led stick to the side of your temple on your head like the Androids in "Detroit Become Human"? I hope to get an answer before San Diego Comic Con 2018. Hopefully, if not, then it's cool.

  7. Avataaar/Circle Created with python_avatars Redstone says:

    My blue led works on a 9v

  8. Avataaar/Circle Created with python_avatars argilaga says:

    Very nice, I didn't know LEDs have a nonlinear region, good to know for my projects since I use LEDs to limit the voltage when I charge batteries

  9. Avataaar/Circle Created with python_avatars argilaga says:

    Very nice, I didn't know LEDs have a nonlinear region, good to know for my projects since I use LEDs to limit the voltage when I charge batteries

  10. Avataaar/Circle Created with python_avatars Waleed Ahmed says:

    red and green LED works perfectly with 3v cell

  11. Avataaar/Circle Created with python_avatars Wild Borego says:

    resistor

  12. Avataaar/Circle Created with python_avatars Frank Zen says:

    you're burning it out, brah…

  13. Avataaar/Circle Created with python_avatars lânchánđời nguyễn says:

    but the led will work strongest with high current and volt how for it doesn't too much.if you use 9v 200mw battery,so connect two leds sequence.if you use 3v 3w,so connect the leds parallel and it also work with high bright.

  14. Avataaar/Circle Created with python_avatars KRUNAL PANCHAL says:

    what is the maximum current of standard LED… .. ?.. LED like in this video….

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