Dr Ronald Stiffler SEC technology

[Slider2732]

Great news...
I persisted with the 10.1MHz crystal, but built it again on a breadboard to test some ideas.
The 'range' is now 2ft 4" or 711mm 
How ? the simple addition of what we would normally do with a Slayer Exciter - add a reverse polarity LED from Emitter to Base !
It can now partially run a neon without holding it (AV plug is partly blocking it in the pic below) and power a couple more loads, while not affecting that resonant condition for the distance extension.
The LED also allows a simple check that the circuit is on and the crystal is sitting correctly in its holder.
Transistor being used is a 'lowly' C945, in comparison to the MPSA06, 2N2222A, MPSA18, C3198 and other known good exciter transistors.

Thoughts then turned to how Lidmotor ran one 13.56MHz circuit from another and I wanted to find 10MHz crystals. Went out to the shed and found what I think was a Ham radio or CB junker board back in the 80's. It has loads of slightly different 10MHz crystals !

[itsu]

Hi Itsu,

I have pondered on this and the first thing would be to utilize resonant voltage increase of tuned LC circuits right already in the xtal oscillator itself as a first step.
I mean to place a tapped LC circuit into the collector of the xtal oscillator to step up the 13.56 MHz signal to as high as possible with such transformation.  See this LC circuit how I mean:
https://overunity.com/17249/dr-ronald-stiffler-sec-technology/msg522125/#msg522125  The oscillator circuit can remain the same you have now, just remove the 1 kOHm or the choke coil from the collector and insert the LC tank there.  The L coil here could be wound on an RF toroidal core you may have from Amidon to have high Q for the tank. 

Another possibility is to use the air core coil itself (called here as L3) to step up resonantly the 13.56 MHz collector current to a relatively 'high' voltage. See this sketch here:
https://overunity.com/17249/dr-ronald-stiffler-sec-technology/msg522451/#msg522451 
What I mean here is this: coil wire #1 would go directly to supply voltage positive and coil tap #2 would go directly to the collector of the transistor. The air core coil should also resonate at 13.56 MHz,  basically this is very similar to the previous tapped LC tank suggestion, just the C is supplied by the air coil self capacitance and by the capacitive load the AV plug will represent with the LEDs too.  This latter 'autotransformer' is more difficult to tune to resonance than the LC tank on the toroid, due to the fully open L air coil.
If these resonant RF voltage up-transformer methods prove useless in the end, then we can ponder on further solutions...   
Gyula

Gyula,

i tried the part in bold above, which seems to work, see screenshot of my oscillator signal.
For the LC tank circuit i used an amidon T200-2 toroid with 26 turns (1mm wire) and a 30pF trimmer cap.

The tap to the collector etc. is 2 turns from the 12V entry point, a 100nF cap is on the output.

The downside is that with this signal the transistor is getting hot quickly.
I put a 5K trimmer pot in the 12V supply line to the tank, which regulates the output (down)

The SN74AC14, the 5V regulator, the BJT totem pole and the MOSFET (IRF840) on the breadboard are not used in this setup!

I probably need to retune the Tank to be more in resonance on 13.56Mhz (it was out of the circuit).
Itsu   

[gyulasun]

Hi Itsu,

Very good, thanks for your efforts.  Here are some refinements if I may, to get a 'nicer' waveform and perhaps less heat for the transistor.

May I suggest to reduce the number of turns from 26 to only 18 and make a tap at 4 turns?

From this link http://toroids.info/T200-2.php  the A_L value is about 12 for this core and 26 turns gives 8.1 uH while we need only around 4 uH, this is approached by 18 turns to get 3.8 uH. I mention this because the scope probe may have 15 pF and your 30 pF trimmer cap is turned fully out, very likely an even smaller than 15 pF overall tuning cap would be needed to tune the tank to resonance with the present 26 turns.  Notice that you may have to retune the trimmer cap when connecting an air coil  via a single wire.

And raising the number of turns for the tap from 2 to 4 would increase collector impedance, hence less AC collector current could flow, reducing dissipation. This may involve less peak to peak RF voltage across the tank due to the smaller transformation ratio, maybe an acceptable compromise.
But anyway, now you have roughly 50-55 Vpp voltage across the relatively high LC tank impedance and this would drive an air core coil (tuned also to 13.56 MHz) via a single wire nicely I suppose.  Then the resonant air core coil may have an even higher oscillating amplitude to feed a 230V LED via AV plug (maybe you do not have a 120 V LED). Try to connect (at least) two-two 1N4148 diodes in series to increase their reverse voltage rating.

A question: what is actual DC voltage feeding the oscillator? (due to the voltage drop across the 5 k trimmer pot)
Edit: if you have an L meter, please check the 26 turns inductance., to learn about reality.

Thanks, Gyula

[Lidmotor]

Slider --- I started using your idea for a power supply and it works great for this project.  That really helped see what happens when you raise the voltage on the crystal circuit.

erfandl----Congratulations on the replication.  It looks good. 

Gyula --- I really like this new 'Wiper Coil' idea.  It works great and might be improved in several ways so it can be adjusted easier.

Here is the video of the adjustable boost power supply in action.  I'm using a 3.7v 18650 battery and running the circuit at 15v.  Lots of light now.

https://www.youtube.com/watch?v=7JDng6iCkZA

--Lidmotor

[Slider2732]

Ah great !
Am finding it to be really flexible and better than presuming a batt voltage or constantly measuring for comparisons as a battery discharges.



The SEC 18-1 has arrived !
Have done an unboxing video and first power up test 

https://www.youtube.com/watch?v=8_6dVHGeVoY
(4 mins)