Flyback Driver circuit.

This is a instructable that contains scematic and pictures of a single transistor flyback driver.

stuff's used:

1x breadboard
1x NPN transistor (with heat sink and a fan)
1x 22 Ohm resistor
1x 220 Ohms resistor
1x transformator (or round ferrite core) with same amount of windings
1x flyback transformator
1x 12 - 15V Powersupply ( i use a battery that gives 15 volt, 400 mA)

And some wires.

Step 1 Scematic of the driver

After i tryed the flyback driver with the primary and feedback windings on the flyback's ferrite core, i thought: *why not try t o use a tiny transformator with same amount of windings to oscillate the process, and so i found out i would try it, and  i got 10 - 15Kv More from the flyback transformator by doing this, so i figured i would make an instructable.

i think the picture is somewhat blurry cause of the size, so il point out the important stuffs here:

* The transistor must have a heat sink.

* Before you put 12 volt in, test the circuit with 3 - 6 volts, and make shure that the transistor doesn't get overheated
(I currently run the circuit with 15 V , 400 mA, and still i cannot feel any sign of heat on the transistor)

i get around 50 Kv from this.

If you have any questions, just ask.

Comments

[daone1]

your circuit didn't work with 2n3055
so i changed a few things in the circuit (still kept 1:1 trans) and it work perfectly
i could drive a plasma globe at 18W input (9v, 2a) which was impossible before
that's amazing with 1:1 trans
happy sparkin~

[Mahitchima]

I imagine you had to swap some cables right? =)

happy it worked for you there! ;)
Happy sparking back! ;)

[OVERLOADED]

I have been using this good transistor it a toshiba D2586 I am able to run it on 12-18volts with no problem but when i try 36v it either stops right away or it works for a few seconds before I hear it whining down and die? any idea why its not able to take this voltage? I do have the datasheet for the transistor if you wnat to see it , also can you recommend any other transistors that can handle higher voltages?

[Mahitchima]

12 - 18 volts to 36 volts is a big leap dont you think =)?
Also, try checking how much Current the transistor can handle! =)
I have experienced a 500 volt transistor blowing up infront of me, using a 12 volt battery! :O

I have only been trying 4 different transistor, which i desoldered of PCB's from old computer screens and televisions :)

i desoldered every transistor on the PCB's from 3 different televisions, and 1 old computer screen.

i just googled em for specifications to find the ones i could use =) some work, some doesn't.

[OVERLOADED]

well I wanted to try to see if it can handle it, I looked at the datasheet and it says about 5A DC or 10A pulsed, but I have no idea what the max voltage or current input should be? it says that Vcbo is 1500V, Vceo is 600V, Vebo is 5V,collector current is 5A DC and 10A pulsed,base current is 2.5A,,,so I have no idea what these mean exactly I know what they are but still? so maybe your more familliar any ideas? I also got about 3 diff TV PCB's with lots of good stuff on them that I can always salvage, and most good transistors come from the same board you find the FBT on most ppl dont know this. the toshiba trans i got has not died yet when so many others have at 36 volts. I also google the parts but some are impossible to find same goes for FBT's.

[Mahitchima]

do you use a battery that got 36 volt output?
or, what kinda PSU do you use? ^^

I will do some researching the transistor that you got there :) i am really curious now.

By the way, do you use my scematic or not? cause in case you use a tiny transformer with very very thin mag wire this is not good when handling much Current (as it got more resistance) that might also be your problem, i suggest you just to check if you feel any heat on feedback or primary =)

[OVERLOADED]

yes i use two 18 v power tool bats or sometimes a 12v adapter with 500mA

[OVERLOADED]

well if you want i can email you the datasheet on it to save you time.
no i did not use your schematic, but now that you mentioned it yes i was using regula thin wire unspliced I was thinking about this before and its probably the problem its very thin wire not mag. there is no heat cause i was runing it on 12v but it was not working with ext feed and prim, but the ext prim worked in combination with internal feed.

[Mahitchima]

i have downloaded the datasheet =)

i would try using a bit thicker wire :)

what kind of resistors are you using in the circuit? 22 and 220ohm?

[OVERLOADED]

ok great so have a look at the datasheet and tell me what you think make sure its entitled 2SD2586 thats what my datasheet calls this trans but on the actual trans it dont say 2S? oh well i am sure its still the same one, what does your title say?

yes I used the thin wire cause it was handy at the time and easier to wind thru the slot of the ferrite.

the resistors I am using are 220R 5W and 22R 1/2W ,,i couldnt find 2W. I hook them up along with a single trans to my FBT, so its a simple circuit like the ones you have seen many times on the net.

I am not sure what the resistors part of the simple circuit does? i think its a voltage divider but no one explains as to what it does or how the current actually flows in the entire circuit, usually they only explain the feedback thing, can you please explain to me how the entire thing works along with what the resistors do? please explain a simple circuit not yours as it may be a little diff.

[Mahitchima]

All i know is that the primary makes interferrence in the feedback, and makes the transistor to short circuit, so that it becomes pulsed DC.

The 2 Resistors i havent really done any serious research on, But as the 22Ohm goes to minus, means the feedback voltage get's to ground easyer than it goes to plus, i think this has something to do with the short circuiting of the transistor also.. but i am not quiet sure, i can only make simple hypothesis about this :p

i have also tryed different variations of Resistors (always higher from "+" than from "-" though,Meaning: 22ohm -> 220ohm. or 1000ohm minus -> 2000ohm plus so maybe if you want to regulate the current and voltage of the circuit, you may try changing them, so that you draw some of the current through em (means less heat on transistor and everything else) (this is also only a hypothesis though)

Experimenting is fun when you have gotten it to work (y) makes progress in your understanding of the circuit.

[OVERLOADED]

yes that what i know too, but the resistor end of it I have no idea?

I think for sure it makes the cycling of the feed back go one way rather than another because one resistor is higher value than other but why even use the other then? ohhh well.

i havent fooled around with diff resistor values because i need to understand what they are doing before i attempt to make changes that make sense to me, for sure once i know then i can def make improvements if necessary, same goes for improving the trans maybe by using diodes that have a volt leakage of enough to run the trans but protect it from high return spikes and over saturation then i could run it up to 36 v perhaps. but everything i am saying is just hypo as i really have no idea of the exact workings of this circuit.

maybe we can chat on gmail instant chat? do you know how we can exchnage email add? without leaving them here? i have done this before with someone else but not sure cause he did it for me.

[aclark17]

I haven't gotten this to work, it turns my 12v supply into a pulsed dc voltage, max of .71v, wth.

Can you be more specific about your transistor?

[Mahitchima]

This is what happens in this circuit:

The primary coil makes a magnetic field, disturbing the feedback coil, and causing the transistor to short circuit. (as far as i have been finding out with a bit research)

it will turn DC into high frequency "AC", so you can use it for your flyback or other high frequency tranformers.

The transistor i use is a E13007F2- 804 NPN silicon power transistor.
I have been trying to find specifications for this transistor, but i havent had much luck, although i have used other NPN epitaxial silicon transistors that have worked just the same as this does. (only reason that i used this instead is that the others got a bit hot, compared to this)

Have you tryed measuring you'r voltage with AC instead of DC on your multimeter?

[aclark17]

I found out I was using an LPS supply, Ive since converted a computer power supply into a lab supply, works great, but I had in a TIP3305 transistor, was so hot it burned my fingers xD

I happen to have an epitaxial npn I was using before, Ill try it again and post what I find, with the new supply, the circuit seems to be working normally now, aside from the transistor heat (at only 3.3v too!!)

Thanks for your response :D

[OVERLOADED]

when there is small voltages there is usally higher current ( amps).

[Mahitchima]

I'm happy that it worked out for you there Aclark! =D
yeah, a computer PSU is nice when working on projects like theese!
have you mounted the transistor on a heatsink then, since it gets that hot?

No problem! i respond as fast as i see a comment ;)!

[aclark17]

Yeah I have an epitaxial that I think I got actually from the CRT TV I got the flyback from, along with various heatsinks for them, but I salvaged also from an old Pentium III cpu the heatsink/fan combo and drilled a mounting hole and threaded it with a tap wrench, so I planned on fixing it to that, but ran into power supply issues, so I took it off an tried various other transistors (before realizing the issue was power and not the transistor power dist) with a regular transistor/FET heatsink without a fan. It got WAYYYY hot, but it wasn't the epitaxial, just a random power transistor I picked up from radio shack on a run. It has pretty high specs and Im not sure its best suited for this application, so when I get around to trying out the other ones I have, if I have any different results I'll share :)

Thank you for the instructable, it and the schematic were fairly easy to follow, and not complicated, but gives great results, and that's how its done! :D

[Mahitchima]

Nice!
seems like you got it going great there! ^^

They tend to get hot o.O , one of mine even exploded, it said "psssst, then Bang!" and it flew pieces everywhere xD

im happy that it is fairly easy to follow and that it gave great results :)
keep going!

may i ask what your planning to use it for?

[aclark17]

Nothing too specific, for me most of this stuff is more about the making of it and not so much the use ;)

But I do want to make a plasma speaker to mess around with :D

What do people usually do with things like this? lol

[Mahitchima]

sorry, breaks down molecules.

[Mahitchima]

well, its nice to use as a driver for a tesla coil (just for fun)

or a jacobs ladder maybe ^^

you can use step up transformers with this circuit to charge capacitors and use em to fire a coil gun.

well there's much =), but i guess only for educational purpose or fun =)

one thing though, sparks make Ozon, and Ozon kills pretty much everything, so you can kinda make ozon and put it through water, so that the water becomes unharmfull to drink.

you can use ozon to bleach, or disinfection (like in water) so that they avoid using so much chlorine, ozone Breaches down molecules .

yeah well, not shure i am 100% correct, but this is what i know :p

there may be people checking out here that might got more things =)

[OVERLOADED]

So basically you found that a 1:1 transformer acts like a feedback so you have now an external feedback to drive your transistor but how does this improve it ? is-int the feedback in the FBT good enough? also are you using the primary of the FBT or did you wind your own? I have found that if you put a wire between the return and the wire that goes to the voltage divider it improves the arc also another discovery I made to drastically improve your arcs( brighter, bigger, longer,louder) is to hook up a capacitor in parallel between your output wires I made a small simple homemade one and am now getting about 90kv.

[Mahitchima]

I found that the whole circuit was easier to wire up with a 1:1 transformer, i also Noticed that wiring both feedback and primary on the flyback transformer didnt always become perfect, i also beleive using a 1:1 transformer makes it all a bit more stable.

However, it might be that my turns on the flyback ferrite core was bad, although they seemed pretty perfect and tight.

i am happy with the results from this circuit =) the 1:1 transformer also made it easier to test if the process oscillated, by hearing the high frequent sound, before i just hooked up the flyback on my breadboard in series with the primary on the "1:1" and flyback.

i wound my own feedback and primary on the flyback, before i tested the "1:1"transformer, now i have only wound the primary on it.
i was not happy with the built in windings, the flyback started making weard noises after a while.

I have also tested my homemade capacitor on the output, dangerous powerful sparks coming out from it ! ^^
if you put a powerful capacitor on the output of the flyback, you will get strong bright loud sparks, but you dont get that high frequent non stopping spark though.

[OVERLOADED]

Yes I guess it depends how you want to run it, most ppl do preffer to make there own external winds as they can adjust them to there liking, its a good way to experiment, I have tried making 10p and 4f ext on my FBT and used a 2n3055 but it did not work, in fact i had to end up using the FBT feedback in order for it to work with my other transistor, the 2n3055 just never worked for me?. right now I usually run my FBT from CFL circuit it works great and adding a homemade cap really gave awsome high rep rate sparks that look like the ones used in a tazer.

[Mahitchima]

You can also make own windings around a round ferrite core ( a round one because it takes less time) = )
i guess the normal is 4f and 8p, if i am not wrong ^^
i got no experience with the "2n3055" however, a friend of mine used this transistor with my scematic, and got it to work though. :)

[OVERLOADED]

yep but I like to see what can be done with the winds in FBT itself, I like to see what they can do with simple transistor drivers, CFL or electronic ballasts, have you ever tried hooking an EB to the primary of your FBT? they produce great results because they output about 500-600VOC with the right freq to run the FBT I think around 15KHz in a square wave pattern and since they are self resonating you dont need to hook any feedback , simply hook it directly into your mains and into primary of FBT, but make sure the FBT you use has at least 11 pins on the bottom, they only seem to work well with those types.

[Mahitchima]

What's an EB?

[OVERLOADED]

EB is what I use short for electronic ballast

[Mahitchima]

I havent tryed that yet = ) but why should i since my circuit gives just as great result =)

remember the VOLTAGE in this circuit is not that important.
it is the Current that get's turned into voltage that's important.

Ofcourse you need voltage but:

More current in = more voltage out

[OVERLOADED]

thats ok im happy your good with what you got, but if you want even longer purple arcs then get a FBT with only 11 pins on bottom (10 in U and 1 outside) and hook it to an EB either a CFL circuit with high wattage or you can buy EB it gives about 600V .5-.9A with proper square wave pattern, feed this to you primary and your in business. dont run it long as it may heat FBT , one guy had his in oil.

well you should use at least 12-18volts if not more depending what your circuit or transistor can handle and about no more than 2 amps since FBT are limited to about that anyways or was it 2-4A ??? more amps means a hoter quiet purple arc, not sure if more amps means more voltage on output? but if you pass it thru cap youd get amaizing sparks (fat,long,brighter, louder and depending on cap high rep rates looks continuous.

[OVERLOADED]

Your FBT looks big is it two of them or just a big one? it looks like it may be one of those that have internal cap.

[Mahitchima]

it is only 1 Flyback transformer by the way :)

it might look big cause of the close up pictures.

[Mahitchima]

It has an internal cap that i can hook up to the output if i want to = ) i havent really tested it though, i've been using external caps =)

[OVERLOADED]

well it looks like it has two barrels? so I figured it might be one of those that have cap inside, and you say it is, but you say you have the option to use the cap or not ? hmmm really I tought it was hooked to the cap internaly so you have no choice but to use the output from thr cap,, Ok well why dont you try it then I am sure you will get better arcs or sparks.

[Mahitchima]

There is 2 pins (which is not in the "half circle") on the flyback, that's the cap =) it charges everytime i use it anyway, so i have to discharge it after use.

i have been on that thought :) will try

[OVERLOADED]

first of all how many pins on the U pattern?
ok so you got 2 extra pins aside from U ok and these are for cap?
so your telling me that you have the choice to have arcs thru cap or without cap?
all I know is that if you have a cap in parallel to the HV out and HV return then you will get better sparks so try connecting to internal sparks and see what happens ,,if cap is in series it will not work but i believe its in parallel.

[Mahitchima]

U pattern = 10 pins

1 pin outside the U pattern which is HV return.

and 2 other pins outside the U pattern which is the capacitor :)

so yes, i have the choise to arch either through or without cap ;)

if i wire the cap in paralell i will probably get better sparks, but not a spark with high frequency i think.

i will might try this = ) but im kinda afraid my output is so big that the cap will die :p

[OVERLOADED]

wow I never seen one like that but ive only seen two so far lol
you should try it for a second and see what happens, why are you worried? tell me what u run it at now, give me input voltage and amps and I assume ur still using same circuit right, if its 12v then dont worry , hook the cap on and see what it looks like , but judging from your picture they actually look like sparks already coming from cap?

i think your cap can def handle it, but you can always hook an external cap to the output leads and bypass the internal cap for now.

I would not worry , on mine I use a CFL circuit that outputs maybe 1000v and maybe 380mA , it says on the lamp 120v 380mA 23W it looks ok by itself I get an arc about 10mm long then it puls to 15mm and becomes sparks, but when i hook it to cap it gives about 20mm sparks about .75" on start very intense ones . how long is your arc now? pls make sure u get precise measurements in mm.

[Mahitchima]

My arcs are at most 5 cm without the capacitor :)

i use a 15 volt 390mA battery to run it :)