Thane Heins Perepiteia.

[Groundloop]

@gyulasun,

Thanks for checking out the cores. I have also searched the net and have the same conclusion.
I have made the input and output coils the same so I can test the cores both ways. I'm currently
soldering a oscillator circuit now. First run in a couple of hours.......................

Thanks,
Groundloop.

[gyulasun]

@gyulasun,

Thanks for checking out the cores. I have also searched the net and have the same conclusion.
I have made the input and output coils the same so I can test the cores both ways. I'm currently
soldering a oscillator circuit now. First run in a couple of hours.......................

Thanks,
Groundloop.

Very good! 

If I may give some hints: 
---try using higher values for R1, the 470 Ohm seems too low for me (peak collector current may exceed core saturation and the goal I believe is to aim for the maximum flux change from zero current to max possible current BELOW core saturation.
---insert a 10-100 Ohm series resistor between the cathode of diode D2 and + battery pole so that you could monitor its voltage drop as an indication of the (charging) current flowing back to the battery from L4 coil.

Thanks,  Gyula

[Groundloop]

@gyulasun,

Yes, you are 100% correct. The amp draw from the battery at first run was so high that both the
coil and the transistor got hot. I will find a resistor (R1) with a much higher resistance. Good news
is that the circuit did run without any smoke. 

Changing resistor now........

Groundloop.

[Groundloop]

@Group,

Circuit is running from a lead acid battery, 12,23 V.  Without feedback the circuit uses 0,15 A.
When I connect the feedback the input usgae drops to 0,08 Amp. Measurements is done
with a moving Iron analog meter and is approximately only. More measurements must
be done before any certain conclutions. But it seems to me that the system is capable of
coupling magnetic flux from the input core to the output core by using a short circuit coil.

BTW: The R1 is only needed to start the circuit so I used 580K.

Groundloop.

[EDIT-1] The moving Iron amp meter affects the circuit. When I remove the amp meter the input current increase a lot.
            To get the amp down again I just connected an air core coil in series with the plus on the battery.
            Now the circuit runs a very low input amp.

Groundloop.

[Liberty]

@Groundloop,

Would it be of value to replace D2 (diode) with a bridge rectifier and add a 100uf cap or larger on the output of the bridge rectifier?  It looks like D2 only offers half wave rectification, where a bridge might offer more output.  Just something to think about.

Have fun...