Suggest you replace the resistor R2 with a 1K Ohm trimmer connected in series with a 220 Ohm resistor (or experiment with different values of resistor, 560, 680, 820, 1K, 1.2K, 1.5K) to see how it affects the performance of the LED. After you get a more satisfactory result, you can further adjust the value of R1 to get better result if possible.
Make sure that the transistors are connected correctly and the LED has not been damaged by the reverse voltage from the inductor. Maybe you can also add
a diode 1N4148 connected in parallel with the LED but in reverse direction to protect the LED from breaking down by the reverse induced voltage .

The components selected for this circuit I posted are optimum for its efficiency any deviation from the circuit could result in poor performance/and or low LED luminosity.

Actually, I think tkng211's suggestions were referring to the original circuit that electronicsnewbie posted in his opening to this thread.

hgmjr

 

Hey hgmjr,

You proposed a 100uh inductor. The circuits in this thread indicate a 470uh. Can you explain how you concluded that a 100uh would still work? I'm not challenging you, just curious how you worked it out.

 

Hey hgmjr,

You proposed a 100uh inductor. The circuits in this thread indicate a 470uh. Can you explain how you concluded that a 100uh would still work? I'm not challenging you, just curious how you worked it out.

I must have clicked on the wrong entry in the catalog. My intent was not to change the value of the inductor. My intent was to recommend an inductor with a very low DC resistance.

I would stay with the 470uH inductor. I would just make sure that the DC resistance was down in low single digit ohms value.

hgmjr

 

It is similar to the one you posted, but this one is more efficient.... and can be built to be really small if the "dead bug" style is used (see pics)...

More on this circuit in my blog. The 2N3904 isn't capable of conducting enough current to drive the LED to full brightness (15 to 20 mA). Using a 2N4402 or PN2222A, or better yet a BC337 or SS8050 will really brighten your day.

 

More on this circuit in my blog. The 2N3904 isn't capable of conducting enough current to drive the LED to full brightness (15 to 20 mA). Using a 2N4402 or PN2222A, or better yet a BC337 or SS8050 will really brighten your day.

I would be interested in giving your circuit a try if you could supply the exact parts list for the circuit.

 

More on this circuit in my blog. The 2N3904 isn't capable of conducting enough current to drive the LED to full brightness (15 to 20 mA). Using a 2N4402 or PN2222A, or better yet a BC337 or SS8050 will really brighten your day.

Not only did my circuit drive a White LED at full brightness, it drove 9 white LEDS..... http://youtu.be/6zVOcND-FuQ

 

Nice to see you back again. You were gone almost a year.

Just curious, did you design your circuit from the ground up BM? I'm not trying to stir, and I regularly use designs from other people and repost them, so that isn't an issue either way. From what I can tell acme has the same exact design.

I'm still going to use it for the AAC book eventually, complete with multiple LEDs.

Are the 9 LEDs in series or parallel?

 

The link to the old blog no longer works. Here's my replacement blog.
http://www.rustybolt.info/wordpress/