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Need help with flyback transformer inverter

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Rey

New Member
Hey guys, I had an old monitor laying around, and came across some schematics for a 30Kv power supply, and so I have been trying with little success.

Here are the schematics I'm using: Simple High Voltage Generator: Low Voltage DC In, up to 30 kV Out

My problem here is that across my Vcc input, I have a resistance of only 1.1Ω

I am using 2SC2625 NPN transistors, and a 20v/3.5A power supply with short circuit protection to drive the inverter. I know my transistors are correctly wired and my drive and feedback windings are correct, as the power supply sends out a sort of 'beacon' to check if the circuit is still shorted, and in this time I am able to produce a small arc. Does anyone have any suggestions to help me get this thing up and running?
 

audioguru

Well-Known Member
Most Helpful Member
1) We don't know which transformer you used.
2) we didn't look-up the spec's for your Oriental transistor to see if it will work in this circuit.
3) We don't know if your transformer will work at this fairly high frequency.
 

crutschow

Well-Known Member
Most Helpful Member
If you want help from any of us I suggest you buttom your garbage mouth.
 

blueroomelectronics

Well-Known Member
Jacobs Ladder, Hmm interesting I suppose if I needed to build a Frankenstein's lab. HV experiments just don't do it for me.
 

Preher TV

Member
flybacks don't require feedback, the inverter circuit driving them does,but only IF the inverter circuit was designed with a feedback circuit. The schem. Rey linked to does not, it is a simple push pull style inverter with no feedback required.........


Rey, do you know you have a good FBT? Is it new? have you done a ring test on the primary winding?
 

Preher TV

Member
Jacobs Ladder, Hmm interesting I suppose if I needed to build a Frankenstein's lab. HV experiments just don't do it for me.

LOL....Yes a Jacobs Ladder fit in nicely at Dr. Frankenstiens lab.....I don't do alot of HV experiments myself but I do find myself working on and troubleshooting alot of HV circuits at work.....:D
 
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blueroomelectronics

Well-Known Member
Well HV knowledge is very handy if not essential when dealing with CRTs, Plasma or CCFL. It's the bane of modern digital electronics though :)
 

bountyhunter

Well-Known Member
After being knocked into the middle of next week by a high voltage TWT supply I had to design, I am not going to encourage a newbie to play with flyback transformers.

Good luck.
 

Preher TV

Member
I am sorry as an old Sony engineer (197o-) and an englishman, LOL, Sony used this technique.

no need to appologize, I made a mistake in what I said anyways, if you look at the Schem he posted the feedback coil is being used.......LOL:eek: don't know what I was thinking at the moment, I'll blame it on not enough coffee....
 
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tcmtech

Banned
Most Helpful Member
I made a battery powered one in high school. One day I used it to electrify the locker row and shock some freshmen with it when they where leaning up against the lockers trying to look cool! :eek:
I had to use myself as the ground plain to get it to work so I was getting shocked just as much as them when I did it. It was mostly just a warm tingle though. ;)

But man it was funnier than hell to watch them jump and then cautiously poke at the lockers trying to figure out what just happened to them! When your unprepared its quite a surprise!:D:D:D
 

Rey

New Member
flybacks don't require feedback, the inverter circuit driving them does,but only IF the inverter circuit was designed with a feedback circuit. The schem. Rey linked to does not, it is a simple push pull style inverter with no feedback required.........


Rey, do you know you have a good FBT? Is it new? have you done a ring test on the primary winding?

Thank you for actually trying to help.

I know the HV winding and primary windings are good, I pulled the flyback from a Envision EN-980e Monitor that ran quite well, with no issues. It is one of the newer type, with all the windings and the HV diode cast in some sort of yellowish acrylic. I located the HV return, and using a simple 12vdc supply I have been able to produce arcs of only a couple millimeters.

I have no clue what a ring test is, but if you were to explain it to me, I'm sure I could perform one.

There is a sticker on the base of the flyback that reads "SAMPO", followed by several number-letter combinations. I'll be happy to post them if they are of any help.
 
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