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Can you see whats wrong with this flashing LED project

Discussion in 'LEDs and Optoelectronics' started by RichyBell, Oct 17, 2010.

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  1. RichyBell

    RichyBell

    4
    0
    Oct 17, 2010
    Hi guys im a total beginner in the world of electronics. What iv done is buy the book "Electronics for Dummies" and one of the practicle parts of it tells you how to build a flashing LED using a 555 IC. I dont have a 330 ome resistor so i thought id design it on "cirtuit wizard" because i know you can test your projects on there.

    As you can see from the attached picture im not able to get it to work but i have no idea why. Iv tried by best to follow the scematics but it still doesnt work. The picture is of the current flow during the testing process im sure you guys will understand it.

    This is a list of what parts iv used
    555 timer
    vr1: 1-m potentionmeter
    r2:47k resistor
    r3:303 resistor
    c1: 1-uF capacitor
    c2: 0.1-uF capacitor
    LED
     

    Attached Files:

  2. LTX71CM

    LTX71CM

    182
    0
    May 23, 2010
    You've connected the ground of your 9V power supply improperly, it needs to connect on the other side of the LED.

    Edit: Like This.
     

    Attached Files:

    Last edited: Oct 17, 2010
  3. RichyBell

    RichyBell

    4
    0
    Oct 17, 2010
    Hi thanks for the reply i made the change and when i hover over the LED it still says no amp's or watt's? im sure everything is connected correctly though
     
  4. LTX71CM

    LTX71CM

    182
    0
    May 23, 2010
    It's been a while since I've used a 555 but every looks good. You have a weird loop coming from the Pin 4 connection but I think it's purely visual and connects properly.

    VR1 being at 0% is probably affecting your simulation. VR1 should always be between 10 and 10M OHMs.
     
  5. jimwill48

    jimwill48

    22
    0
    Sep 2, 2010
    Flashing LED Circuit

    Funny thing about this Circuit from Electronics for Dummies.. I built the circuit and could not get it to work with LED. But Sub'ed a 4ohm speaker in place of the LED and could hear the pulses..when LED are in place the LED just stays on solid.....
     
  6. davenn

    davenn Moderator

    13,901
    1,970
    Sep 5, 2009
    which infers that the LED is flashing faster than your eye can detect :)
    slow down the timing period of the 555 timer

    D
     
  7. jimwill48

    jimwill48

    22
    0
    Sep 2, 2010
    That's what I thought but by using the pot I could get the audio pulses down to a couple a second but an LED will still stay solid. I got to admit I got tired of trying to make this work at the time, and I haven't looked at this circuit in a while and guess I should just for my own education..try a new 555 and pot, ecte. I'm still very much a new-by at this....

    J

     
  8. jimwill48

    jimwill48

    22
    0
    Sep 2, 2010
    Hummmm..went back and re-built this circuit, works great now that I can tell the diff between a 47ohm resistor and a 47K ohm resistor :eek:.

    J

     
  9. davenn

    davenn Moderator

    13,901
    1,970
    Sep 5, 2009

    there ya go :) a bit of educational experimentation well done

    Dave
     
  10. RichyBell

    RichyBell

    4
    0
    Oct 17, 2010
    Thanks guys, iv noticed quite a few errors in this book but hey its giving me a good starting points
     
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