Noob! 555 Timer Help!! (First Post)

Thread Starter

Jimmy7

Joined Feb 8, 2012
8
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
 

Pencil

Joined Dec 8, 2009
271
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.
 

Thread Starter

Jimmy7

Joined Feb 8, 2012
8
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!
 

Pencil

Joined Dec 8, 2009
271
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:

Thread Starter

Jimmy7

Joined Feb 8, 2012
8
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!
 

Pencil

Joined Dec 8, 2009
271
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.
 

Motardo

Joined Sep 21, 2011
22
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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