Will this circuit work when i hook up a battery

Discussion in 'The Projects Forum' started by polotwr, Oct 26, 2016.

  1. polotwr

    Thread Starter New Member

    Oct 26, 2016
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    I need to hook up a 9v battery to power. will this work? never done this before. and i have no prior experience
     
  2. crutschow

    Expert

    Mar 14, 2008
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    Can't tell from just a picture.
    Can you post a schematic?
     
  3. wayneh

    Expert

    Sep 9, 2010
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    Is if your intention to hook your LED to a 9V battery using a 150 ohm resistor to limit the current?

    I'm not sure about the switch pinout and is the orange thing just a wire? Other than those questions, it looks like it will work.
     
  4. polotwr

    Thread Starter New Member

    Oct 26, 2016
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    Yes it is a 5.5-7.5 forward voltage LED
    the resistor is 150ohm 1/8W
    and a 9v battery

    I redid it a little bit after realizing the LED was backward (new pic attached). but still not sure why it is not working
    No light is being emitted

    Sorry about the schematic looking like a child drew it, i drew one up in 30 seconds to attach as it may help
     
  5. dl324

    AAC Fanatic!

    Mar 30, 2015
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    The resistor looks like 1/8W to me. It won't take that much current.

    Edit: Are you sure about the forward voltage? White LEDs typically have the highest forward voltage and that's around 3.5V. My comment was assuming a forward voltage of around 2V.
     
    Last edited: Oct 26, 2016
  6. polotwr

    Thread Starter New Member

    Oct 26, 2016
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    I apologize it is 4.6V-6V forward voltage
    and it is a 1/8W resistor

    I attached the data from the manufacturer
    it is a UV LED
     
    Last edited: Oct 27, 2016
  7. gramps

    Member

    Dec 8, 2014
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    A UV led won't emit any visible light. You won't be able to see if it's on or not.
     
  8. polotwr

    Thread Starter New Member

    Oct 26, 2016
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    How will i know if it is working?
     
  9. BR-549

    AAC Fanatic!

    Sep 22, 2013
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    Try looking at a uv led with a smart phone or tablet camera. I read somewhere, where some cameras can see IR as a light and some can show UV as a light thru the camera.

    It does work for IR....I've tried that. Testing tv remotes. Haven't tried UV.......but some say it works there too.
     
  10. hp1729

    Well-Known Member

    Nov 23, 2015
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    From a 9 V battery? Not enough current, maybe.
    (edited to add ... )
    20 mA should work. Did you damage the LED when you hooked it up backwards?
     
    Last edited: Oct 27, 2016
  11. polotwr

    Thread Starter New Member

    Oct 26, 2016
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    so with a 9v battery
    a 150ohm 1/8W resistor
    this should work for the LED that needs 4.6-6V forward voltage and 20mA current?

    if the components are correct then all I need is a way to test the function since I guess i won't be able to see any light

    how would i verify the light being functional. is there a testing method or just a multimeter
     
    Last edited: Oct 27, 2016
  12. djsfantasi

    AAC Fanatic!

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    You can try illuminating some dish soap or tonic water. Most glow under UV light.
     
  13. polotwr

    Thread Starter New Member

    Oct 26, 2016
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    even though it doesn't emit visible light?
    the LED is not emitting any light whatsoever. if it was working I understand that UV light is invisible, but would it also emit visible light as well
     
  14. djsfantasi

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    The UV light, although not visible, reacts with the tonic water and produces visible light.
     
  15. polotwr

    Thread Starter New Member

    Oct 26, 2016
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    very good, so to put it simply.
    Even if my light is working I will not be able to see any light coming from it when it is on unless I use one of those other methods?
    I appreciate it, do you think the voltage and current are in line for what I am trying to accomplish.
    9v battery to 150Ω 1/8W resistor to LED
    LED calls for 20mA and has 4.6-6V Forward voltage typical and 7V max

    I attached the currenta nd vltage data for my LED
    as well as my schematic, please help me out with what im doing wrong
     
    Last edited: Oct 27, 2016
  16. djsfantasi

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  17. wayneh

    Expert

    Sep 9, 2010
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    I've never heard of a UV LED that doesn't emit visible light. I'm not saying there isn't such a thing, just that I'm unaware.

    You really need to use something fluorescent to test it. Fluorescent dyes absorb UV wavelengths and re-emit light at a visible wavelength. Anything you have that glows in the dark will usually react strongly to UV light.

    You should also be aware that UV light can damage - essentially, sunburn - your eyes without you knowing it until it becomes painful hours later. I wouldn't be too afraid of a single LED, but be careful.
     
  18. djsfantasi

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    Fluorescent? Like tonic water perhaps? Which specifically flouresces to UV light. Easily obtainable rather than sone dyes.
     
  19. polotwr

    Thread Starter New Member

    Oct 26, 2016
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    Yes, My contact at the manufacturer said that it will emit visible light as well

    with that being the case, is my resitor to small? is the current from the 9v not enough? Im losing my mind as to why it is not firing up
     
  20. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Have you checked the battery voltage? Your schematic should work, but you need a 1/4 W resistor. It may be a problem with the resistor. Can you take it out of the circuit and test that it is 150Ω?
     
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