Introduction: How to Make a Fryback!

Picture of How to Make a Fryback!
Here is an instructable on how to make a fryback, the kind of all flybacks!

Materials needed include:
  • Two large ferrite U cores. TSC international is my favorite place for getting ferrite cores. 
  • Plenty of magnet wire, 28 gauge is preferred.
  • Electrical tape, any color but black. Get the really nice 3M stuff, the cheapo dollar store stuff is crap.
  • Teflon pipe thread tape.
  • Liquid electrical tape.
  • An exacto-knife.
  • Super glue.
  • Regular wire, preferably silicone insulated.
  • Lots of time.

This is mostly a pictorial instructable, because pictures are a lot easier to follow than words.


Step 1: First...

Picture of First...
...find a cardboard or PVC tube that fits on your ferrite core. 

Then wrap that tube in about 6 layers of electrical tape, and then proceed to wrap some magnet wire around it.
  • Do not take the magnet wire all the way to the ends of the tube.
  • Don't make the entire winding layer more than a half inch wide. If you do there will be insulation issues.
  • Wrap tightly and make no crossed turns.
After that, put a dab of super glue on there to hold the wires in place. 

Step 2: Second...

Picture of Second...

...wrap 5 layers of teflon plumber's tape around the coil. This will provide most of the transformer's inter-layer insulation, something critical to prevent it from going up in flames. 5 layers should be good for 4kV, but I personally wouldn't trust it with more than 2.

To calculate your inter-layer voltage, take the output voltage you're aiming for and divide that by the number of layers, then multiply that by 2.

Say I want 30kV and I have 40 layers. (30,000/40)* 2 = 1.5kV inter-layer voltage, not too bad considering I used 4kV worth of teflon. 

Step 3: Third...

Picture of Third...

...put on one layer of electrical tape, then start winding again.

Secure the wire with super glue, then cut strips of electrical tape and place beside the coil. In the picture there is only one strip (on the left), but two are needed to support the next layer. 

Step 4: Fourth...

Picture of Fourth...

...repeat until your brain melts!

I decided to put 40 layers in my fryback, a task that took me 25 hours! Albeit I was watching TV at the same time, but it's still a daunting task. 

Take care to not break the wire coming out of the center! If you do, fun's over. 

Step 5: Fifth...

Picture of Fifth...

...solder wires to the magnet wire and glue the ends in place with super glue.

This will prevent you from breaking the fragile magnet wire. I chose to use silicone insulated wire because it absorbs super glue like a sponge, but it's not necessary. 

Step 6: Sixth...

Picture of Sixth...
...cover the newly made secondary coil in liquid electrical tape, about 4 coats.

The liquid tape preforms 4 functions:
  • Prevents water from getting in.
  • Prevents the electrical tape from sliding off of the cardboard tube.
  • Adds some insulation.
  • Makes the thing look that much better.

Step 7: Seventh...

Picture of Seventh...

...make the primary coil.

This isn't too tricky, all you need is some wire and craft skills to make one. I chose to make a 4+4 turn primary (wires' doubled up so it appears like 8+8).

Step 8: Eighth...

Picture of Eighth...

...assemble your fryback!

I used the friction of the paper tubes to hold my cores in place, and when powered up the magnetism clamps the ferrites together. One tip, don't use a metal fastener. It will inductively heat and steal most of your power!

Step 9: Addendum and Video

That's about it! You can power your fryback up with any driver you want, be it a zvs or something else. Remember though, if you attempt to generate too much voltage the fryback will die an untimely death. This is mostly a higher current transformer rather than a higher  voltage one, but nonetheless it sure is impressive.



petersoldan (author)2016-09-14

very nice,impressive and informative.thank you.

leviterande (author)2013-07-18

Hi is the output of this AC right? however when I make a smaller version of this I only get pulsed DC

AndrewC12 (author)leviterande2015-02-13

Depends on your power supply, not the transformer itself.

AndrewC12 (author)2015-02-13

Nice "chicken stick." :)

ualbuquerque (author)2015-01-03

Can I use iron instead of ferrite?

AndrewC12 (author)ualbuquerque2015-02-13

Probably, but I wouldn't recommend it. You'd have huge energy losses from eddy currents and problems with heat.

dillonxti (author)2014-02-18

try it on a half bridge.

robot797 (author)2013-10-03

if i want to use this
but i need realy high voltage

what must i change?
i ask this becaus thes looks good enough for my vacuum tube flyback

The MadScientist (author)2013-07-16

Hi nice transformer, I have made a few as well but only a few kV like 4kV.

I would like to know if you think that shellac soaked card would be a worthy insulator rather than tape for HV?

It could work, but it won't work well. I'd just invest in a roll of kapton tape; might as well given the time and expense of winding all that wire!

Thanks for the advise the kapton tape looks like some pretty good stuff I'll give it a try.

DylanBurg3r (author)2013-06-16

What I meant was order one

DylanBurg3r (author)2013-06-16

Hi, could you please post the dimensions of your transformer core , I need to prefer one

CoronaAndOzone (author)2013-06-01

I've found, even when working with 38 AWG wire, that only 2-4 layers of Teflon tape is enough insulation (and, with 26 AWG, it isn't necessary at all).

somebody12345 (author)2011-12-23

Something in the background started smoking

that was smoke from the metal he was using ... its harder to see below a certain point

Alex1M6 (author)2012-01-29

Just wondering could you measure the DC resistance of the one you made and post it here?

Umniscient (author)2011-07-05

After each layer, should I bring the wire back to the beginning of the coil, or can I just continue back and forth?

pwnag3 (author)Umniscient2011-12-24

continue back and forth

geckomage (author)2011-10-31

nice instructable. it looked like you had either 3 or 4 outputs on the "primary" was one of those a feedback coil? or is this a pure a/c transformer with a centertapped primary? and when you said you doubled up the wire. did you wind two sets of wire on each lil "8 wind" and solder the ends together? also was that regular stranded wire or solid wire used on the primary? could you possibly provide a diagram of exactly how you winded the secondary? was it from left to right and right to left? or did you start over and make a continuous pattern from left to right (as an example) also, what kind of current can you draw from this without destroying it? also what kind of circuitry would i need to just plug this thing into the wall? i know a straight short would not be good so any pointers you could give would be great! feel free to mail me or simply update the instructable a bit! :D

jzhan (author)2011-10-12

What do you mean the wires doubled up? Sorry, I don't understand whether you made a 4+4 or 8+8?

qukapiku (author)2011-09-08

A very good instructable !
Thanks a lot.

hmm > My mission is to get the electronics hobby booming again! <
That`s a real ARE doing that ;) .

pwnag3 (author)2011-08-24

nice project, a few questions though, what EXACT core was that? and how much wire did you use?

grenadier (author)pwnag32011-08-24

I haven't a clue

pwnag3 (author)grenadier2011-08-24

no prob ill just wing it

-max- (author)2011-07-23

monster Jacobs latter!!

-max- (author)2011-07-23

that looks incredible! like the old ones

The MadScientist (author)2011-07-15

What current is coming out of that?

Also I've got a similar switch mode NST core that I've been meaning to do this with and I am planning to space the layers of windings with some kind of hard plastic so I can insulate it with paraffin wax after would this work?

Umniscient (author)2011-06-25

Hi, grenadier.
Most of the old AC flybacks I've seen have a disk shaped secondary (like yours), but the newer DC ones are more evenly wound. Why is this, and are there any certain advantages to either form?

grenadier (author)Umniscient2011-06-26

They are still disks.

Umniscient (author)grenadier2011-07-02

So, multiple disks...

grenadier (author)Umniscient2011-07-03

Yep, but with diodes connecting them.

Umniscient (author)2011-07-02

The diameter of the hole in this picture is the same as the previous?
That's a lot of layers.

mattccc (author)2011-06-22

i see you use a chicken stick lol!

Chingasman (author)2011-06-21

so for every layer there should be two wires hanging out. correct?

grenadier (author)Chingasman2011-06-22

No, you just wrap the tape over the wire, kind of like this:

Chingasman (author)2011-06-21

are those all your power supplies in the back griound? this is why i follow grenadier

NathanaelScheffler (author)2011-06-21

It looks more like blue fire than electricity! Amazing! What was the approximate total cost of the project?

sparktech (author)2011-06-20

im confused do you ever cut the magnet wire or do you just bend it over the electrical tape? sorry if this seems like a stupid question...

grenadier (author)sparktech2011-06-20

If you cut the wire then electricity can't flow through it!

sparktech (author)grenadier2011-06-20

so you do just fold it over the electrical tape?

grenadier (author)sparktech2011-06-20

Yes pretty much.

_Scratch_ (author)2011-06-20

This would make a nice carbon arc torch, also, do you think it can melt steel?

grenadier (author)_Scratch_2011-06-20

It was melting steel!

Riptide100 (author)2011-06-20

Amazing work, yet again :)

Kaptain Kool (author)2011-06-19

Cool! This looks like a pretty Awesome Sauce thing to have in your mad scientist lab!

About This Instructable




Bio: Physicist
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