Using the circuit from the Renewable Energy UK website I breadboarded an LED dimmer. Again, if I could draw a circuit diagram on the computer I would.
I used just one "string" of three LEDs with a 140 ohm resistor in series. Apart from the 555 timer IC (59p (I think) from Maplin) all the components came from my drawers (ooer, missus). It worked extremely well: the LEDs not dimming completely, as predicted, but at "full" brightness they looked bright enough.
Measuring the voltage at "full" I found:
10.2V across the three LEDs in series, i.e. 3.4V across each LED.
And a lot less power was consumed by the electronics - I used a (small) BC546 transistor which didn't even get warm.
An interesting side effect of taking the photo: when pointing the digital camera at the LEDs the camera's CCD sensor shows you the mark/space ratio on the screen!
There's more to do, as I now want to combine the voltage regulator with the dimmer.
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