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Rudimentary beginners question with LED

Discussion in 'LEDs and Optoelectronics' started by zenbytes, Sep 14, 2013.

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  1. zenbytes


    Sep 14, 2013
    Hi all,

    I am just starting out in the world of electronics and have encountered a problem doing the most simple of circuits (lighting a LED)

    Please see my link for the circuit diagrams.


    I am puzzles as to why the LED will not light up in the first circuit (it looks complete to me) and I can only guess as to the reason that it does not work is that it is shorted somewhere?

    The second circuit sees the LED connected between two rows rather than in the same row and does work.
    I would be very grateful if someone could explain why?

    Many thanks!
  2. GonzoEngineer


    Dec 2, 2011
    You need to understand the connections inside the breadboard.

    The rows are connected horizontally between the red and blues lines, bur are connected vertically in the center sections.

    Take an ohmmeter and check the continuity internally, then you will understand.
  3. davenn

    davenn Moderator

    Sep 5, 2009
    Hi zenbytes
    welcome to the forums :)

    OK here's a corrected update to your construction. Note I have also now got the resistor in the positive line to the LED
    Thats not totally critical but it is conventional
    Also with some added info on breadboard layout



    Attached Files:

  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    Jan 21, 2010
    The other good advice is to connect the +ve to the top of the breadboard, and the negative to the bottom.

    It makes it harder to connect things to the wrong rail, and because circuits are also drawn that way, it makes it a lot easier to construct many things.
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