Any frequency really, from 1hz to 1mhz and same from duty cycle, right now I am using 10% duty cycle and 4 hz for led (test)
but I can change the frequency and duty cycle in realtime... I can post the program if some want to experiment with it.


Basically I think for a MEG, a low duty cycle is best with a higher frequency, but I dont know what a magnetite core can handle


Once all my circuit will be resolved, I will need to print a 3d core in PLA and i will fill it with magnetite without any glue

1MHz is out of the question with a 2N3055.  20kHz would be pushing it.  1kHz to 5kHz s/b OK.

1MHz is out of the question with a 2N3055.  20kHz would be pushing it.  1kHz to 5kHz s/b OK.

See? That's exactly what I mean. The TK MiniSlayer operates at much higher frequency than one would expect a 3055 to be capable of. I just got it off its high shelf, dusted it off and measured its operating frequency. It's running at 681 kHz. You don't get that kind of plasma globe display at low frequencies.

Here's the Base signal, with 12 V input to the circuit:

See? That's exactly what I mean. The TK MiniSlayer operates at much higher frequency than one would expect a 3055 to be capable of. I just got it off its high shelf, dusted it off and measured its operating frequency. It's running at 681 kHz. You don't get that kind of plasma globe display at low frequencies.

The losses through a 2N3055 at that kind of frequency are horrendous.  Change transistors to something more appropriate and it will be a SUPER slayer.

I don't know what is the max frequency a magnetite core can handle, I will need to experiment.

The frequency range that any core can be used at depends on the specific type of core material you are using.
Iron and iron powder and silicon steel are typically only useful at very low frequencies. Different ferrite compostions
are suitable for differrent frequency ranges depending on the specific ferrite composition. Usually manufacturers
of different types of core materials provide details in data sheets on what frequency range their different core compositions are
suitable for. Also, you should be aware that some LEDs do not work as good at higher frequencies as other types of LEDs.
I have two sets of white LEDS from different sources that look pretty much the same on the outside, but only
one of the sets of LEDs works well at frequencies in the high kHz or MHz range. The other LED type only lights
at low frequencies. You should test your LEDS with a signal generator and series voltage limiting resistor over a
range of frequencies to see what frequency ranges the LEDs can light at.

All the best...

Please note my video test from my previous post was a 10% duty cycle. Also youtube converted my video in bad quality I dont know why...


I have 2 others transistors rate at 7mhz. BU208A, well rated higher then 2n3055, but for my initial test i will stay with 2N3055 because I will start with lower frequency at first.

A GBW product of 7MHz does not mean that the transistor works at 7MHz.  It means that at 7MHz you have to pump as much power in as you get out.

Yes, you are right, there is probably more power being dissipated in the transistor than is being put to useful use. It works quite well with a TIP35C, too, and perhaps wastes a bit less power.

if the magnetite cannot handle that much frequency, i guess the 2n3055 will able to handle what i need, what strange is i read somewhere that magnetite have a very high frequency, even some free energy device was using this because of this property (muller i think)


its why I want to use magnetite but without epoxy, core in PLA, fill the PLA mold and hope it work!