Kapanadze Cousin - DALLY FREE ENERGY

[TinselKoala]

  Here's the board that does both 0 - 100% duty cycle, which is independent of the frequency, which can also be modulated.
http://www.rmcybernetics.com/shop/pulse-modulator-ocx
  I just don't know how to tie something like this to the yoke/grenade circuit. 
  The Tl494 board that I previously posted only modulates the frequency, but not the duty cycle.
   
   Anyways, I've been playing around with the scope, but would like to know the way to figure the math on the running frequencies, as there is no read out on this scope.  I've been using the 100x probe for now, to monitor and tune the Kacher by just placing it near by, but that won't tell me at what frequency it's running at, as that will vary with the distance the probe is away from the signal source

Measuring frequency with an analog oscilloscope:
http://www.youtube.com/watch?v=teXXF0a_WoI
Basically you count the number of cycles in a time interval and divide. Peaks (or zero crossings) per second = frequency

[TinselKoala]

I remember it in a SSTC of yours.  Could you remind me what was the source of the feedback signal in that implementation?

The feedback to the 4046 PLL can come from an e-field antenna near the resonating secondary, or from inductively or capacitively coupled signal off of the bottom of the secondary. I've had good results from just a one-turn loop loosely around the very bottom of the secondary. For the e-field pickup you can use a separate cmos logic gate, with input from the antenna and output to the PLL chip. For C or L coupling you can use a small toroidal transformer, the "ground" or bottom of the resonating secondary makes one or two turns through the toroid and then an output winding of ten turns goes to the PLL chip. Sometimes it will work with just a wire pushed up inside the secondary.

[ariovaldo]

Probably I'm not in your level of knowledge guys, but I'm doing some tests, a lot to say the truth, and I would like to share something that I noticed in one of my tests. Sorry if it looks like dumb, but to me it was interesting.
https://youtu.be/LM9H4UEa7Uk

I'm using microwave capacitor and the drain resistor, probably is affecting the results.

Ariovaldo

[ariovaldo]

In this video, instead use a simple diode array, I used a diode bridge, with one side connected to the ground.


https://youtu.be/OBcRAJYloQ4[

Ariovaldo

[verpies]

These are to me the correct approaches and what I'm focusing on.  I use a crystal controlled frequency generator driving a "WaveDAC" component to get my sine wave.  From there I dump the pseudo sine wave into a Class-D power amplifier and on to the toroid transformer. 
There is a little redundancy with this design but it allows me to use off-the-shelf components.  The clear advantage of this is solid locked frequency and volume control allowing me to ease up the power transfer

That is a good approach if your power amplifier can handle the frequency.

.  The current hurdle I'm faced with is the reaction of the toroid transformer when connected to the grenade and induction heater coils.  If you have the resonating capacitors incorrectly set, you get huge spikes that destroy the Class-D amplifier. 

Yes, for maximum power transfer and minimum reverse energy flow, an inductive load should be counterbalanced with matching capacitance and the DC ohms of the load should be equal to DC ohms of the power amplifier's output.  All in accordance with MPTT.

Designing a proper snubber network has been a challenging task thus far.  My goal is to come up with something that absorbs this reaction and bleeds it off as heat while protecting the amplifier.

Actually a scrubber network is the worst solution because it lowers efficiency of the entire circuit.
As an alternative you can try to precisely match the real and imaginary components of your complex load impedance according to MPTT and/or use lossless clamps, like I have shown in the last two schematics. These clamps don't waste the reflected spike energy as heat but return it to the power supply instead. Lossless clamps require bifilar transformer windings as shown on the schematic.  Their effectiveness is illustrated in this video.