Dr Ronald Stiffler SEC technology

[Slider2732]

Lidmotor - will likely mod mine to have the voltage and current meter.
It may be that a good distance away and using something like coax to connect to the circuit would be the way to measure.
Quick tip: do you have the plastic bulb part still from a bulb that got disassembled ?
Put that over the LED's and it should allow for looking at the output. Also would work well for output comparisons to a mains driven version of a bulb.


Speaking of which.
Here's a pic of a Lowe's bought 9W bulbs innards, being driven at 12V with the SEC 18-1.
It's perhaps interesting because the bulb 'features' components on the actual board, as has been a problem with some replication attempts.
Connecting the L3 to the +/- with an AV plug works. Brightness increases with a clip lead.
The DT bulb also works great on the SEC, at certain points within the C1 var cap tuning range.
(there's a gap in the ring of LED's, because I accidentally Dremel'd right through it when taking it apart and had to jumper with a soldered wire).

[itsu]

Redid my tank circuit, now 18 turns and the tap on 4 turns from the 12V.
The 23pF trimmer cap is (with 8pF probe connected) set to a minimum value.

Connected up to the 100nF cap my L3 coil which is connected to the copper tape taped to
the alu backside of my 230V led strip with 2x 1N4148 diodes from plus to minus of the led strip.

The led strip now gives more light then it did with my FG (20Vpp).
Input voltage was 12V from a battery (5K pot on input all off (0 Ohm)).

The input was calculated by the scope to be 2.18W, see red trace / value.
(Blue is input voltage battery, green is input current battery, yellow is output at trimmer cap)


Itsu

[gyulasun]

Hi Itsu,

Very nice sinewave and huge peak to peak value across the tank, very good job with the LC tank, thanks for all your efforts.

Probably a 120V LED array would already give even higher brightness with this setup (I know you do not have and no problem).

Maybe the transistor is still warming up if the circuit is run for several minutes, a certain part of the 2.18 W input power surely heats it up. It is sure that playing with the tap position and use 5 or 6 turns for the tap can further improve the matching between the collector and the LC tank (hence the possibility of reducing dissipation), when L3 is also in place with its LED load, this is a dynamic interaction.  I just notice these, I am not asking you to refine this matching any further, what you have achieved is very fine already.

May I ask you to show the voltage waveform on the collector of the transistor with respect to the negative ground? I am curious where are the lower peaks of the collector voltage, how close they approach the negative rail? (please use DC coupling on the scope input)
You surely checked somehow whether coil L3 is fully in resonance at 13.56 MHz when the LED is attached? 

One more thing what may be interesting: whether there is a difference in brightness when you drive the same LED array in this same setup with the AV plug from the L3 coil and not with the back plate capacitive coupling? 

When driving the LEDs with the AV plug and you place a puffer capacitor across the DC output of the AV diodes (i.e. across the LED strip input), then the DC voltage could be measured, hence the AC voltage could be deduced at the top of L3 (I know the top of L3 is floating AC wise.)   A 22 or 47 uF 250V capacitor may be enough.
(I assume that in this present test shown in the photo the center point of the two AV plug diodes is floating, right?)

It is possible though that in the shown setup if you attach a short piece of wire to the center of the two diodes, or you simply touch it by finger, then the brightness may increase (similarly when the Doc shows this with a Alu mass touching the diodes point). 
If you recall the Doc showed the diodes common point was connected to the negative supply rail in one of his videos, when thhis LED array was simply placed very close to his L3 coil.  If you test the diodes point connection to the negative,  then the retuning of L3 may be needed because the capacitive coupling to the top of L3 would become higher, causing some resonance detuning in L3.  If this happens, you may need to remove 1 or 2 turns from L3. 
Thanks,
Gyula

[Lidmotor]

All----I finally got my cheap function generator in the mail and got it to do a true replication of Dr. Stiffler's experiment.  The
Wiper Coil' I made was critical in getting this to work at 13MHz.  This effect does work at other frequencies depending on what coil you choose.

https://www.youtube.com/watch?v=GCR3HoYeuCA

----Lidmotor

[itsu]

Hi Itsu,

Very nice sinewave and huge peak to peak value across the tank, very good job with the LC tank, thanks for all your efforts.

Probably a 120V LED array would already give even higher brightness with this setup (I know you do not have and no problem).

Maybe the transistor is still warming up if the circuit is run for several minutes, a certain part of the 2.18 W input power surely heats it up. It is sure that playing with the tap position and use 5 or 6 turns for the tap can further improve the matching between the collector and the LC tank (hence the possibility of reducing dissipation), when L3 is also in place with its LED load, this is a dynamic interaction.  I just notice these, I am not asking you to refine this matching any further, what you have achieved is very fine already.

May I ask you to show the voltage waveform on the collector of the transistor with respect to the negative ground? I am curious where are the lower peaks of the collector voltage, how close they approach the negative rail? (please use DC coupling on the scope input)
You surely checked somehow whether coil L3 is fully in resonance at 13.56 MHz when the LED is attached? 

One more thing what may be interesting: whether there is a difference in brightness when you drive the same LED array in this same setup with the AV plug from the L3 coil and not with the back plate capacitive coupling? 

When driving the LEDs with the AV plug and you place a puffer capacitor across the DC output of the AV diodes (i.e. across the LED strip input), then the DC voltage could be measured, hence the AC voltage could be deduced at the top of L3 (I know the top of L3 is floating AC wise.)   A 22 or 47 uF 250V capacitor may be enough.
(I assume that in this present test shown in the photo the center point of the two AV plug diodes is floating, right?)

It is possible though that in the shown setup if you attach a short piece of wire to the center of the two diodes, or you simply touch it by finger, then the brightness may increase (similarly when the Doc shows this with a Alu mass touching the diodes point). 
If you recall the Doc showed the diodes common point was connected to the negative supply rail in one of his videos, when thhis LED array was simply placed very close to his L3 coil.  If you test the diodes point connection to the negative,  then the retuning of L3 may be needed because the capacitive coupling to the top of L3 would become higher, causing some resonance detuning in L3.  If this happens, you may need to remove 1 or 2 turns from L3. 
Thanks,
Gyula

The L3 coil with leds attached resonates (using my FG red lead only) around 15Mhz, and with a
ferrite rod inside (slightly) i can adjust it to 13.5Mhz allthough the brightness of the leds gets less.

Doing this trick when attached to my tank does not work somehow, its a strange (for me) interaction, like
flipping a switch the leds flip on or off depending on the 5K pot setting (from 0 Ohm to higher,
then back to 0 Ohm) and/or the setting of the trimmer cap (different when using the probe or not).
I will need to add turns on my L3 coil to have it resonate (with the FG) at 13.5Mhz.

I did not use the AV-plug setup you mention up till now, only with the 2 diodes in a loop across the leds
plus/minus, but will try it.
The center point of the diodes is always floating, attaching a (V)ground does improve the brightness.

At the moment, the 5V regulator and the SN74AC14 etc. is still powered from the 12V, so that also needs
to be included into the 2.18W input, i will remove those items.
The transistor does heat up somewhat, but less then it did before the tank mod.

Will tinker around some more later today including showing the waveform of the collector to ground.

Itsu