Lasersaber strikes again. A joule thief king ?

[a.king21]

TinselK, have you turned the mains off to ensure you're not picking up stray rf?

[MileHigh]

TK and All:

Have a look at the LM3909:

https://www.youtube.com/watch?v=87xMbWM8qz0

Just about everything said in that clip was my experience also.  I built my first LM3909 circuit in 1977.

MileHigh

[Pirate88179]

TK and All:

Have a look at the LM3909:

https://www.youtube.com/watch?v=87xMbWM8qz0

Just about everything said in that clip was my experience also.  I built my first LM3909 circuit in 1977.

MileHigh

That was a cool video.  Hard to believe it was that long ago.  I must be getting really old... 

Someone, somewhere on here told me of a new 555 that will run down to like .35 volts and uses very little power.  I can't find the thread from that post and hence, can not find the part.  It is supposed to be what is under the gray blob of epoxy on those led garden lights.  (I have some that I have tried to dig under that blob with no success yet)

Do you have any idea what those chips might be?  Years ago you suggested using a 555 for the JT circuits and the only reason I didn't want to do that was they required more voltage than I was working with at the time.  Whatever these "new" 555 chips might be would change all of that.  As you know, those garden lights only start with 1.2 volts max after charging, and will run an led all night so, whatever that chip might be is way more efficient than any of my 555's I have here.

Thanks,

Bill

[conradelektro]

Have a look at the LM3909:
https://www.youtube.com/watch?v=87xMbWM8qz0

If you look at the data sheet of the LM3909 (is attached) you find on the first page:

Low current drain, averages under 0.5 mA during battery life.

The 0.5 mA power drain is about what I achieved with my circuit, see:
http://www.overunity.com/14591/lasesaber-strikes-again-a-joule-thief-king/msg402222/#msg402222

The road to very low power draw:

- 100 Hz flash rate
- very short pulse
- low LED current (rather dim LED)

In my circuit the pulse is already very short but happens at about 5 KHz, the LED current is already low (dim LED). By having more windings (thinner wire) on my core the frequency can be lowered. How can the pulse be made shorter?

Remarks:

The LM3909 uses a peak LED current of 45 mA at 1 Hz (slow) or 1 KHz (fast) to have a bright flash.

The supply current of a NE555 is between 5 and 15 mA (5V to 15V), therefore it is of little help.

LaserSaber's special core and the 2N1304 transistor seem to operate at less than 10 µA (at about 12 V) on average.

Greetings, Conrad

[TinselKoala]

TinselK, have you turned the mains off to ensure you're not picking up stray rf?

No, I haven't, not for that particular device. This circuit is tuned to match the wireless transmitter's operating frequency which is quite a bit higher than our mains frequency. I do have others that will glow from the house mains emanations though.