Noob! 555 Timer Help!! (First Post)

Discussion in 'General Electronics Chat' started by Jimmy7, Feb 11, 2012.

  1. Jimmy7

    Thread Starter New Member

    Feb 8, 2012
    8
    0
    Hi Everyone,

    This is my first post, so firstly..

    Hello!, My name is James, I'm from Birmingham, England. I'm a qualified domestic electrician but know very very little regarding circuitry type electrics.

    I have been trying for about a week now to create a simple astable / square type timer circuit to control an LED.

    I am getting no results from a 555 timer, I have tried swapping timers, resisiters, capacitors. I am getting no results.

    The only thing I can see that might differ to any of the tutorials is the supply. I am using a 9v DC battery, but no tutorial I have read, as really specified the input.

    I'm sorry everyone for being a bit of a noob here, can anybody help? As I'm seriously ready to throw in the towel!!

    Thanks again!!
    James
     
  2. Pencil

    Active Member

    Dec 8, 2009
    271
    38
    Can you post some sort of drawing/schematic of what
    you have tried?

    Tell us exactly (part numbers and/or values) the parts
    you have.

    Explain in detail, the best you can, of what is happening
    or not happening.

    I'm sure we can figure this out.
     
  3. Jimmy7

    Thread Starter New Member

    Feb 8, 2012
    8
    0
    Hi Pencil,

    http://www.555-timer-circuits.com/up-down-fading-led.html

    The first tutorial I tried was the link above, as far as I'm aware all the components are the same, the only difference being that the cap I used was 25v not 16v?

    I will get more information of the components I have used.

    Thanks again for your reply!
     
  4. LDG

    New Member

    Feb 10, 2012
    4
    1
    Maybe this will help.
     
  5. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,535
    I have a different set of tutorials that is based off this site. They are actually part of the AAC eBook.

    The 555 Projects

    What are you specifically trying to do?

    This is probably the simplest circuit out there to flash an LED.

    555 Hysteretic Oscillator
     
  6. Jimmy7

    Thread Starter New Member

    Feb 8, 2012
    8
    0
    This may be a stupid question but the resistor I am using are blue, and 1/2w could this be what it causing the problem?

    Thanks for the tips so far!
     
  7. Pencil

    Active Member

    Dec 8, 2009
    271
    38
    Just to make sure you weren't given a bad
    example I threw that circuit on a solderless
    breadboard. I does work as shown. The only
    differences I had was I used a 2N4401 transistor
    and used a 30K resistor (instead of a 33K), because
    that was what I had at arms length.

    Here are some suggestions for you to check:

    1. Identify pin numbers of the 555 (look for reference notch or dot).
    2. Identify pins of transistor (emitter, base, collector).
    3. Identify + and - of capacitor correctly.
    4. Identify anode (+) and cathode (-) of LED correctly.
    5. Check all connections before applying power.
     
    Last edited: Feb 11, 2012
  8. Pencil

    Active Member

    Dec 8, 2009
    271
    38
    Not if it is the correct value (33KΩ or 470Ω).
     
  9. Jimmy7

    Thread Starter New Member

    Feb 8, 2012
    8
    0
    I have checked all of the above over and over and still no joy, I have tried switching polarity on all components, I have swapped components, I have starting from scratch about 6 times. I literally have no ideas.

    Thanks for your help guys, I think I'm gonna have to throw in the towel, I really don't get it.

    Thanks again!
     
  10. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,535
    Have you tried my circuit? It has a complete drawing of how to wire it.
     
  11. Pencil

    Active Member

    Dec 8, 2009
    271
    38
    Don't give up.

    I'm sure it it something simple.

    Tell us what transistor you are using, we can check
    pinout of that first, it is not uncommon to misunderstand
    the locations of the pins.
     
  12. tracecom

    AAC Fanatic!

    Apr 16, 2010
    3,869
    1,393
    Post a closeup photo of your breadboard. If it's a wiring problem, someone will spot it.
     
  13. Motardo

    New Member

    Sep 21, 2011
    20
    2
    Maybe a dead battery? Try connecting just the battery, LED, and 470 resistor in series. If it lights, then at least those three components are good.
     
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