Mini ISSTC V - First light! 5.11.10

dingo27, Sun Oct 24 2010, 09:39PM

Hi, i started work on another TC i had on shelf quite long time, but never really get to work it properly. Today i made another H bridge with four IRF530, MUR860G, 1ohm gate resistors and ferrite GDT (not a yellow one this time smile ). Fol filtering there are two 1000uF/250V caps

TC is winded on a syringe, i think it was 20ml one, topload is my favourite choice made out of beer cans :) Resonating frequency is kind of mystery to me, i think it definetly will be more than 1MHz.

I will try to get it cheap and simple as possible. It will be ISSTC, feedback from bottom secondary CT which i have good experience with previous project and worked well. Othervise it will be just 74HC14, transistor bridge for feeding GDT (an alternative for gate drive IC), some interrupter and whatever i will need to do to make it work at such a high frequency. This coil is still nightmare to me, as it did not worked with any of my previous circuits (only as SGTC) so its quite a challenge for me.

To do>
-wind a primary form in a shape of V, 5 turns will be enough
-make some platform for it from wooden floor planks, if i dont find some more interesting material

IMG 5826 IMG 5835 IMG 5838 IMG 5850 IMG 5847

IMG 5851 IMG 5854


all pictures will go straight here first! > Link2

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5th november 2010 - First light! Worked like a charm on first try, although it has some problem with self starting

IMG 5861 IMG 5862 IMG 5864 IMG 5866

will work to get proper starting, this time it worked only with 17V common with logic supply

Same day: i pushed it little harder, 50V input and sparks between primary and secondary occured. I was able to achieve 3cm sparks, and with so little power ( 12V and 1.5A max). It seems i will need to build V primary if i want or not, to push things little further.
Re: Mini ISSTC V - First light! 5.11.10
Mads Barnkob, Mon Oct 25 2010, 08:09PM

Its a neat little coil with some good design details in order to make a compact design, so it hurts my heart a bit to see steel spacers used as conductors to the capacitors, I am not at all sure this could be your problem, but there is issues with steel at high frequencies, turn some spacers out of brass on a lathe or find something else in a better conducting material .... brass, copper or your grandmothers silver forks... :)
Re: Mini ISSTC V - First light! 5.11.10
dingo27, Wed Oct 27 2010, 05:44PM

Thanks, i think it is brass with some shiny stuff on it. Metal contacts soldered on caps are also brass, with solder on it.

Besides fets holder i think there is no iron. (i hope)
Re: Mini ISSTC V - First light! 5.11.10
dingo27, Fri Nov 05 2010, 02:30PM

update