Lasersaber strikes again. A joule thief king ?

[d3x0r]

(oops ended up restarting this, thought I hadn't sent it, sorry for double post)
OUBrads with an LSJR...https://www.youtube.com/watch?v=UhqT-Yodv1Q


from playing with joule ringers, and LED loads, lots of LEDs in series draw the same current as a few LEDs in series, but require more voltage

[d3x0r]

http://laserhacker.com/?p=420


3D Printed SJR Flashlight Prototype! - Instant Charge Battery Free Li...


http://vcclite.com/_pdf/VAOL-10GWY4-LED-10mm-white.pdf
http://media.digikey.com/pdf/Data%20Sheets/United%20Chemi-Con%20PDFs/SMH_Series%20_Mar07.pdf

[conradelektro]

http://laserhacker.com/?p=420

3D Printed SJR Flashlight Prototype! - Instant Charge Battery Free Li...

It is a really nice move by Lasersaber to publish his experiments in all detail.

I will rewind my transformer to the 1:2 ratio tomorrow or on Tuesday (enameled copper wire 0.4 mm diameter, may find some Litz wire).

The "magnet shaker" power supply is neat. And it works because the circuit needs very little power.

I wonder why the MPSA18 does not burn through at 70 Volt (Lasersaber mentions a 70 Volt charge of the electrolytic capacitor in the video). The VCEO of the MPSA18 transistor is 45 Volt absolute maximum? But there might be a huge Voltage drop over the DC resistance of the 200 turn winding?

Notice that the transformer steps down to the LEDs, so, the circuit needs higher Voltage in the electrolytic cap (may be at least 12 Volt)?

70 Volt at the primary (driven by the collector/emitter of the MPSA18) will lead only 35 Volt to the base of the transistor (secondary step down 2:1). And the Voltage drop over the primary (200 turns, may be 20 to 30 Ohm) will help the transistor to survive. Will have to measure that.

Greetings, Conrad

[d3x0r]

It is a really nice move by Lasersaber to publish his experiments in all detail.

I will rewind my transformer to the 1:2 ratio tomorrow or on Tuesday (enameled copper wire 0.4 mm diameter, may find some Litz wire).

The "magnet shaker" power supply is neat. And it works because the circuit needs very little power.

I wonder why the MPSA18 does not burn through at 70 Volt (Lasersaber mentions a 70 Volt charge of the electrolytic capacitor in the video). The VCEO of the MPSA18 transistor is 45 Volt absolute maximum? But there might be a huge Voltage drop over the DC resistance of the 200 turn winding?

Notice that the transformer steps down to the LEDs, so, the circuit needs higher Voltage in the electrolytic cap (may be at least 12 Volt)?

70 Volt at the primary (driven by the collector/emitter of the MPSA18) will lead only 35 Volt to the base of the transistor (secondary step down 2:1). And the Voltage drop over the primary (200 turns, may be 20 to 30 Ohm) will help the transistor to survive. Will have to measure that.

Greetings, Conrad

it would be a stepdown; but it's still got a spike because of the sharp turnoff... it's not just 'volts in = volts out' but 'how fast current changes in  = how fast current changes out'
that is an interesting note though; I should reverse my coil.
the LEDs are also driven low.... it's a low voltage spike that hits the base ...

[SkyWatcher123]

Hi folks, Hi d3x0r, thanks for sharing lasers stuff here to keep us up to date.
That is really a nice light he made with the shaker power source.
I picked up a few days ago, a baygen freeplay radio, with an output jack already mounted, meant for an led, it outputs 3 volts.
The steel coil, hand cranked generator can charge 2 aa nimh in series and the amp meter shows 40 milliamps.
Meaning, a little step up oscillator to raise voltage and a few cranks of this thing can charge several or a larger capacity capacitor.
I wonder if the akula ferrite core is absolutely needed to show the kind of results he is demonstrating.
I have e-cores from small to large and flyback cores.
Going to have to focus on this setup for a bit.
peace love light


edit: oh yes, anyone know if the 200 turn collector coil is wound as the first or second coil, thanks.