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Registered Member #3062
Joined: Wed Aug 04 2010, 02:07AM
Location:
Posts: 22
I just recently finished building my first VTTC, it as an 811A and I used steve wards design however, I have tried with and without a Bypass capacitor connected to the leads of my MOT power supply. Or perhaps, my primary doesnt have enough turns in order to resonant with my secondary coil form.
Registered Member #195
Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111
c2 190pf seems a little low have you tried anything else like 2200pf? In reality your primary circuit should be resonant with your secondary. Do you have a o-scope and signal generator if not a simple detector with meter and a 555 oscilator circuit might suffice for tuning
Registered Member #3062
Joined: Wed Aug 04 2010, 02:07AM
Location:
Posts: 22
Im afraid I dont have an oscilloscope or signal generator at my disposal. by chance, would the capacitor that came with the MOT work for my tank capacitor C2, its rated at 2100VAC at about 0.84uF ?
Registered Member #2899
Joined: Wed Jun 02 2010, 06:31PM
Location: Deinze, Belgium
Posts: 255
This is my circuit from a Tesla coil with one 811a. Now I am making my secondary coil, and then I will measure the resonance frequency, to determine the primary coil and capacitor. Success with yours, and keep us informed!
Registered Member #3062
Joined: Wed Aug 04 2010, 02:07AM
Location:
Posts: 22
I tried increasing the capacitance to 6KV at 2.2nF still no luck so far. Will a VTTC still produce little sparks if poorly tuned like a poorly tuned SGTC ? or will it not produce anything and not resonant whatsoever
Registered Member #195
Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111
c2 is going to have to be a doorknob cap or a russian ceramic cap and preferably mica caps. any of those should handle the primary tank frequency and have a low ESL and ESR. you may need some basic equipment a multimeter, frequency counter and a pulse generator, you can make a pulse generator with a 555 and mic4429 fet driver. a detector made from a 1n34 and capacitor can be used to determine amplitude. your primary must have the same or 10% lower frequency than your secondary you will need some basic equipment. do you have any pictures
Registered Member #3062
Joined: Wed Aug 04 2010, 02:07AM
Location:
Posts: 22
I do have a picture or two of my VTTC so far. As far as the parts you suggested I use I have very limited equipment and electronics at my disposal, I am about to be a junior in college, and just an amateur enthusiast at best. I could order those those several parts but that may take awhile.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
1. Try swapping the connections of grid coil 2. Calculate resonances and tune ! Make a tapped primary, get a proper RF ceramic capacitor with kVAr rating or make a MMC out of MKP/FKP caps.
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First VTTC possible resonance issue
