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From: D Yuniskis on 28 May 2010 01:54
D Yuniskis wrote:
> The only components that you might have a little trouble
> with are the LED and the capacitors. The capacitors
> will have a black stripe along one side of the "can".
> This is the "-" side (if you examine the drawing, you
> will see that the capacitors *are* shown with this long
> black stripe!), The LED typically has one *flat* side
> near one of the two "legs". This indicates the "cathode"
> leg; the other leg is the "anode" (loosely speaking,
> cathode = "-", anode = "+"). The anode leg will also
> typically be *longer* than the cathode leg (though if
> the legs have been cut/trimmed, you can't rely on
> this indication, obviously!). You should be able to
> verify *both* indications: cathode is flat side and
> shorter leg.

Grrr... after all of that, I neglected to make clear:

The anode of the LED is the wide side of the triangular
shape in the *schematic*. I.e.,

* |
** |
*** |
**** |
*****|
**** |
*** |
** |
* |

the anode is on the left in this "illustration".

Note that the anode should be on the *top* in the
schematic drawing -- connected directly to pin 3
of the 555 (this, coincidentally, places the
anode at the top in the "drawing", as well) with
the 150 ohm resistor connected to it's cathode!

If you get the LED installed backwards, it won't
illuminate -- so, you'll think the circuit isn't
working when, in fact, it may well be!

Apologies if I've taken anything else for granted.
:<
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