SJR Looper/Akula based coil – 19 minutes !

Following my previous video, different coil designs and geometries have brought a 19 minutes run today of a normally mains powered LED night light.

The basics are that it’s the Lasersaber SJR Looper circuit, with a madified Akula design of coil.
The Akula construction has a winding of 200 turns 30AWG on top of his coil design. That winding replaces the Red wire on Lasersabers circuit.

Lasersabers SJR Looper:

Wesley narrated video:

Additional info:
The circuit will run from a signal generator outputting 1V, or a 1.5V battery.
9V performs little to no better than 3.6V.
Transistor is an SMD 2N2222A (can be seen in the bottom middle of the circuitboard…just about)
3x3300uF caps from the late 1990’s
Central bolt and nut are from Lowes, approx $1.40 for a pack of 6
Size is #10-24×1 1/2in

My method of bobbin construction is as follows:
Take a thin pills bottle (Walmart thinnest).
Cut/Dremmel a section to correct core inner height.
Using scissors, cut out a section such that the piece will now fit tightly to the core inner when the 2 ends are brought back together.
Superglue the gap closed.
Now cut holes in 2x 1 Gallon water bottle tops and using the central bolt, push it through 1 of the caps.
Put the (now dried) pills bottle piece on next, then the other bottle cap
Secure with the bolt passing through the other end and tightened together with the nut.
At the end of winding, remove the bolt and cap pieces to place the finished coil in the ferrite core.
Cores are from Nebraska Surplus.

The circuit begins oscillations at 1.5kHz, which when the battery is removed instantly falls to 1.1kHz and then steps down slowly until about 10 minutes of run time, where it reaches 1.055kHz. At which point, the frequency increases slowly again, until a resting position of around 1.070kHz. Right at the end, the frequency alters to between 1 and 2.5kHz, rapidly changing. At which point, the coil becomes slightly audible and can be heard to change pitch.

Further info on the progression to this point can be found at the following thread.
Read before thumbing down, not that such persons would do:

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