Kapanadze Cousin - DALLY FREE ENERGY

[Marsing]

just 200kHz (oscilator frequncy) is 500nS still out of nano range!

edit   

T = 1/F

example

1 / 300 KHz  = 3,3333333333333333333333333333333e-6   -->    3,3 micro second
1 / 2   MHz  = 0,000 000 5                                                  -->    500  nano second 

etc ...

If  F = 300 KHZ  AND Duty cycle = 10 %    then     3,3 uS / 10 = 330 nano second
IF  F = 2 MHZ    AND Duty cycle = 10 %    then     500 nS / 10 =  50 nano second.

etc ...   

So . we already got nanosecond pulse using tl494, with condition duty cycle = 10 % AND F = 300 KHz


...

[itsu]

Itsu,

Its strange you still get this 'special' mode as I never saw it at any voltage. One thing that might be worth trying is to increase the inductance of your choke to see if you can lose the effect.

Hi Hoppy,

the choke is extremely sensitive concerning this special mode.
The used 250uH choke is just on the border, when i tested with 800uH, 5.5mH and 7mH chokes, they all caused the Mazzilli to go into this special mode (@24v INPUT).

I will reposition this choke (close to the input terminals) on my circuit to see if the present location perhaps is causing the feedback/oscillations.


Thanks,  regards Itsu

[zcsaba77]

edit   

T = 1/F

example

1 / 300 KHz  = 3,3333333333333333333333333333333e-6   -->    3,3 micro second
1 / 2   MHz  = 0,000 000 5                                                  -->    500  nano second 

etc ...

If  F = 300 KHZ  AND Duty cycle = 10 %    then     3,3 uS / 10 = 330 nano second
IF  F = 2 MHZ    AND Duty cycle = 10 %    then     500 nS / 10 =  50 nano second.

etc ...   

So . we already got nanosecond pulse using tl494, with condition duty cycle = 10 % AND F = 300 KHz


...

but 300kHz with 10% duty cycle is on border, and just 330nS!!!
and TL494's datasheet show just 200kHz!!!
maybe with 2MHz if exist

[TinselKoala]

edit   

T = 1/F

example

1 / 300 KHz  = 3,3333333333333333333333333333333e-6   -->    3,3 micro second
1 / 2   MHz  = 0,000 000 5                                                  -->    500  nano second 

etc ...

If  F = 300 KHZ  AND Duty cycle = 10 %    then     3,3 uS / 10 = 330 nano second
IF  F = 2 MHZ    AND Duty cycle = 10 %    then     500 nS / 10 =  50 nano second.

etc ...   

So . we already got nanosecond pulse using tl494, with condition duty cycle = 10 % AND F = 300 KHz


...

330 nanoseconds is not "nanosecond pulsing" it is "hundred nanosecond pulsing". You are still off by two orders of magnitude. Besides, it isn't the _length_ of the pulse that is critical, it is the rise and fall times. Certainly, short pulses must have even shorter rise and fall times, but if you can oscillate at 300 kHz _and_ make your rise and fall times be under 10 ns, you will be in the right ballpark.  The genuine TI-manufactured TL494, with careful circuitry, can be made to oscillate reliably at more than 800 kHz and with careful output stage pulse shaping can deliver a final power pulse train with the needed nanosecond-class rise and fall times. Don't believe me? See my "TinselKoil 2" videos.

[magpwr]

but 300kHz with 10% duty cycle is on border, and just 330nS!!!
and TL494's datasheet show just 200kHz!!!
maybe with 2MHz if exist

hi zcsaba77,

I have done comparison between TL494 and 3525 PWM I/C and find that both have the nearly the same spec.
The finding on 3525 is it will produce nice waveform to around 200khz any higher i would recommend using PWM I/c:3825 which is able to do 1Mhz max.

For the recent basic Don Smith demonstration to itsu i was using 3825.

I have attach my PWM circuit based on 3825.

-----------------------------------
Side track project-
I have just assembled the 5mhz induction heater today but i'm using slightly inferior available mosfet IRFP450(higher Rds on resistance) instead of IRFP460.
http://4hv.org/e107_plugins/forum/forum_viewtopic.php?142264

Officially this the first time i replicated something that made in Russia and it works base on schematic.

I was able to get metal nail really hot but wasn't able to see glow on nail using variable 30....40volts 10Amps power supply.

I'm using some excess silver-mica capacitor 1600volts 2000pf for this induction heater project which was previously purchased from Ukraine around 2 months back.
"This is to be used in the snubber circuit for the Don smith as found in page 260 of pjkbook.pdf."

For 1.5nf i am using available mica capacitors 560nf x 3 in parallel.

Placing oscilloscope probe nearby the frequency seems started with around 5mhz then it slowly started drifting slightly higher to around 5.2mhz(I think this is due to the silver-mica capacitor is getting hotter)

Current consumption is around 40voltsx 1.6Amp and slowly increasing.