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Poorest Man's SSTC

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LAN_403

Hazmatt_(The Underdog)

Mon Jun 16 2008, 10:27PM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

HEHE, well, not exactly. See the Idea is I'm studying coupling and well, I was trying a triac module using 16 VAC and input via my signal generator but the 15V square wave from the generator just wasn't saturating the triac module enough, so I thought what the hell, I'll just use the Iggy coil driver idea and see if it will work, AND IT DOES! Now mind you I am studying the coupling for a SGTC so I don't need or want big sparks, I just want to see the beating and frequency splitting in the system. The setup gives me about 2kv I would say because the sparks are about 3-4mm overall, so its perfect to be divided down and characterized by instruments. The car jack is to raise and lower the coil so I can see where the optimal response is e.g. see the notches without making something too rigid or permanant. It gives me 17 inches of travel, and on top of that I can insert or remove pipe couplers to gain a very wide margin of coupling. ^^ I think its pretty smart.

Specs:

1000W lamp dimmer
decoupling cap: 30uF 6x 5uF @ 100VAC, and...heh... I'm putting 120V through them... no wonder they buzz. I'll have to put a couple in series. I wasn't looking when I threw it together, so that explains it.
Tank cap: .02uF 4x .005uF, I wasn't sure how well the small 630VAC caps would hold up in the tank but it looks like they're happy.
Primary: I think 42uH, I have to check later, but that's not really all that important
Secondary: 44mH 4.6" secondary 28 AWG ~ 1000T
Output: 3-4mm spark lenght, even shorter then my flyback driver! heheh.

So there you have it, the poorest man's SSTC, that is if you don't have hours and hours to design a PCB, wait for parts or what have you.

Avi

Tue Jun 17 2008, 05:06AM

Registered Member #580 Joined: Mon Mar 12 2007, 03:17PM
Location: Melbourne, Australia
Posts: 410

I managed to make one with a single mosfet flyback driver(mosfet+555+ucc drivers, changed the cap to get a higher frequency range on the 555). It managed reasonable length sparks when a capacitor charged to 240v was connected to it.
Aslo worked changing the 555 circuit for a antenna+invertor chip.
The mosfet had zeners and a mov across it

Reaching

Wed Jun 18 2008, 05:50PM

Registered Member #76 Joined: Thu Feb 09 2006, 10:04AM
Location: Hemer, Germany
Posts: 458

hrhr, i managed to build a sstc with only 3 parts. a mosfet and two resistors. its a simple feedback oscillator and the mosfet needs no heatsink.

a bit difficult to get the feedback coil right, but its the simplest coil i ever build

Dr. Dark Current

Wed Jun 18 2008, 06:23PM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

I've also made a triac sstc before, 5mm sparks or so. The main problem is the speed of the triac, if one could get fast high-current triac module, it would make for a nice OLTC I think.

On the note of super simple things, I once managed to get a HV transformer from photocopier going with just one mosfet, nothing else. Made 1cm sparks from 4 AA batteries.

Arcstarter

Wed Jun 18 2008, 08:46PM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

Reaching wrote ...

hrhr, i managed to build a sstc with only 3 parts. a mosfet and two resistors. its a simple feedback oscillator and the mosfet needs no heatsink.

a bit difficult to get the feedback coil right, but its the simplest coil i ever build

Btw where is that schematic located? I saw it before. I would like to give it another go. Maybe experiment with different component values.

Avi

Thu Jun 19 2008, 12:43AM

Registered Member #580 Joined: Mon Mar 12 2007, 03:17PM
Location: Melbourne, Australia
Posts: 410

what?
is this the 'joule theif' circuit or something?

Reaching

Fri Jun 20 2008, 11:20AM

Registered Member #76 Joined: Thu Feb 09 2006, 10:04AM
Location: Hemer, Germany
Posts: 458

Heres the shematic

Hazmatt_(The Underdog)

Sat Jun 21 2008, 07:36PM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

hehe, part of this is a joke you guys are missing. The joke is that the arc length is miniscule and its a poor SSTC as far as performance goes, but I didn't want huge arcs because I just need enough output to go to a divider and into the scope. See I'm looking for coupling characteristics, so that joke sorta got missed.

Other then that I do have a mosfet driver but remember the primary is copper tubing. Without a decoupling capacitor you're just going to have a hot transistor.

The other problem is I need low frequency switching so I can mimic the spark gap, otherwise I would have a CW amplifier driving the input insted of a triac.

I have yet to really look at the output, and now I have a couple of days off, so I hope this gives me what I'm looking for.

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