Dr Ronald Stiffler SEC technology

[gyulasun]

Hi Lidmotor,
We need to ask mikrovolt where he thinks to use this filter?
I ask this because my impression is he may mean to increase oscillator output amplitude by making impedance transformation.
Dr Stiffler applies filter mainly for the supply voltage rail filtering if I recall correctly. Maybe he used it at other places I cannot recall now.
Thanks,  Gyula

EDIT  I believe mikrovolt means to use this filter either at the output of a low level generator or crystal oscillator, to increase the amplitude of the low output.  This is possible because the output of this filter at the left hand side may have a high resonant amplitude when it is terminated via a single wire by a high impedance load like an L3 coil with the capacitive coupled LED array.
The 50 Ohm resistor on the right indicates the internal resistance of a generator, that is the input of the filter I believe.

[gyulasun]

Hi Itsu,

As I wrote about the tank and L3, both are a parallel resonant circuit connected in
series via the stray or distributed capacitors. I edited your schematic diagram.
I labeled the toroidal coil as L_t and the self capacitance of L₃ as Cc_oil.  I also included a C_stray capacitor
that very likely 'connects' the 'hv' end of L₃ and the LED array back to the circuit via the
enviroment, closing the two parallel resonant LC circuits in a series connection with respect to
each other. 
Putting this otherwise: we have two LC parallel circuits in series connection via the C_stray capacitor.

This can give multiple resonances: L_t can make a series circuit with C_coil at a certain frequency and the trimmer cap C_{_VAR}
can also make yet another series circuit with L₃, these are the main two additional series resonances
beside the two parallel resonant tanks. 

Maybe this is not so complicated in practice because we have a single frequency, 13.56 MHz
defined by the crystal and some of the resonances may be far from this frequency so their effect
may be neglected.  One thing is sure: you and others found that the output voltage of a generator
reduces when L3 with the LED load on it (attached by a single wire to the hot output) is tuned to
resonance at the generator output frequency.

We may need to further ponder on this. 
Gyula

[Lidmotor]

Gyula---You are right.  Mikrovolt's filter is on the output not the input.  My mistake.  I was thinking of Doc's filters that he used on his circuits inputs. 

--Lidmotor

[gyulasun]

Okay Lidmotor, no problem.
The real "problem" is that with such RF voltage step up transformations by resonant circuits, filters etc,  the energy does not increase what we feed into the circuit at our own expense.   At least, so far there has been no evidence for this.

Of course, it is always useful to have a LED lamp which consumes less input energy than earlier when was bought as an off the shelf product.  And the source of energy can also come from a solar cell when practical.  These are useful pieces of advantage, no doubt.
Gyula

[itsu]

Gyula,

i thought that the L3 in combination with the alu backplate (capacitance) of the leds form a series LC circuit resonant
at 13.5MHZ (15MHz in my case).

The reason for that thought was that my FG voltage dips at resonance, meaning low impedance and high current
which is a mark of a series LC in resonance.

That would mean that i now have a parallel LC (tank circuit) in series with a series LC (L3 + leds).
But i see what you mean with your explaination.

Anyway, i have tried to match the tank LC only (so no L3 / leds connected) with a bigger variable C (6 -60pF)
to produce max oscillations at 13.5MHz.

The screenshot shows the result, but it blows the BC337-40 transistor within seconds.
So i am looking for a replacement transistor that can withstand that power.

Than i will start to match the L3 with leds to be spot on 13.5MHz too (rewind L3 probably).

Blue is collector signal,  yellow the tank output.
Itsu