Introduction: Tesla Coil: Secondary Coil

Picture of Tesla Coil: Secondary Coil

How to get a nice/free winding station set up for a medium to large sized secondary coil.

Step 1: Supplies for a Secondary

Picture of Supplies for a Secondary

To build the secondary coil, you will need magnet wire, a form to wind the wire around. The form can be cardboard, PVC, or other non conductive material tube.

Step 2: Good Place to Wind

Picture of Good Place to Wind

Winding the secondary is the longest most tedious part of making a tesla coil (IMHO)

So its a good idea to find a nice place to wind for hours on end. I picked a shady spot in the backyard.

Grab a stool to sit on, I also recommend a pair of gloves, magnet wire can be pretty rough on the skin after a while.

Also, have a roll of tape sitting near so you can tape down your progress as you go along, its no fun seeing hours of work unwind!

Step 3: Now the Setup

Picture of Now the Setup

This is a pretty simple setup if you have these supplies sitting around. I just flipped a bench upside down, and covered the legs with old rags so the form would rotate easily as I wound the wire by rotating the tube.



ajose4 (author)2014-01-11

Hi,good day.My secondary coil just cutd away from my tesla coil please help me

disappearingshadow (author)2012-04-19

if i used 22 guage wire instead of the 24 magnetic wire do i have to redo it?

nak (author)disappearingshadow2012-04-19

No, you just have to make sure your coil tunes

Good luck, and do some more reading!

cartilige (author)2009-01-16

I wish somebody would make an easy to understand, small, and as un-complicated as possible tesla coil. I'm a long exposure photographer and just want BIG sparks. I'm not AMAZING at electronics but i do have alot of know-how, but all the instructions available make no sense. Will somebody just make it simpler.

knoxarama (author)cartilige2010-07-13

if your looking for sparks, try a microwave mots transformer, use the middle prong on the base plate. big sparks.

one of the best resources for making a tesla coil is - they have years of archives of coil building adivce to search through, or you can join their mailing list and ask what questions that you cant find answers to in the existing knowledge base

nonickname (author)cartilige2009-07-04

Tesla coils are extremely simple. They are just air-cored resonant transformers. Capacitor charges, sparkgap fires, primary coil fires, secondary coil picks up current, bang you have sparks. If you can't get an even basic understanding of tesla coils then maybe it isn't for you..

puffyfluff (author)2008-06-08

I have done a lot of research on trinary coils. They seem cool. I kind of built one, but it wasn't very big. I got 4 foot sparks from 5 amps, though!

me835 (author)puffyfluff2010-05-18

I'd love to see an instructable on it. would you just design the secondary circuit similar to the primary's, except with all tolerances, ratings, and values adjusted accordingly?

ubicomp (author)2007-07-12

I'm just a curious bystander in this conversation, but has anyone thought to try to set that pvc pipe up on a motor to slowly rotate? Then you let the motor do the work while you simply guide the wire. Seems like it would save a LOT of time, given how much wire you have to spool onto it. Just an observation.

critterfluffy (author)ubicomp2010-04-10

actually, when I would one of my coils I used a foot pedal from a sewing machine and variac and a motor.  You use the variac to set the speed of the motor and then you use the foot pedal to turn it on and off.  It works really well and prevents any problems.  Me and another person wound our coil(4.5 feet of it) in about 3 - 5 hours.  Not 100% on the time frame since it was over 8 years ago.

puffyfluff (author)ubicomp2008-06-08

Yes, you can. I bought a 5 RPM motor off of ebay for a buck, and used that. I sat next to it and wrote emails, taking the occasional glance and slight move of the wire feeding mechanism. I actually did it with my one foot one and my 3.5 foot one.

yesss, thats what you do if your crazy.

Nagarjun Bhat (author)2009-12-27

Can you kindly let me know if you wound the wire so closely with your hand??
How many turns per inch could you achieve??

puffyfluff (author)2009-05-14

It is finished or published yet. I'd kind of advise not linking it anywhere else.

I said that? My memory must be failing...

gomjjabar (author)2006-06-06

I'm knew so I don't know the protocol. Should I make comments to this project or just submit an alternate method of winding? I start here: To keep the windings tight and even, before starting the winding, apply 3 or 4 strips of double-sided tape down the entire length of the core. Or, spray a small amount of aerosol adhesive (I 've used 3M Super 77) to the core as you go. Either method einsures close windings, liimited pressure to the wire and your delicate paws. One more advantage is that if you experience a wire break it's easy to make a splice. I've wound at least 10 secondaries fo various diameters and lengths with no problems what-so-ever. CAIO

puffyfluff (author)gomjjabar2009-05-14

Probably make a new one.

lemonie (author)2007-05-12

I'm getting the impression that you don't actually know what you're talking about. Tesla coils are not powered from units anything like arc-welders, and they don't incorporate big capacitors either. L

A Friend (author)lemonie2009-02-16

Hi lemonie, I think the reference to welders is the High frequency TIG welders that also use spark gap technology Regards

puffyfluff (author)lemonie2008-06-09

I was getting the same feeling until you started talking about cap banks, welders and an inverter all together. That might work, but other than that, I don't really think you know that much about tesla coils.

nak (author)lemonie2007-05-12

Got the same impression, but I am still going to stay out of it ;P

lemonie (author)2007-05-13

Tesla coils operate on AC, and you don't need a welder to charge capacitors. L

A Friend (author)lemonie2009-02-16

Hi lemonie, My understanding of Tesla coils is that they work on "Pulsed DC". you might use AC, but, the power supply that you use should rectify this to DC. AC would essentially stop the Tesla coil working. That is, the negative slope of the sine wave will allow the charge that you have sent to the coil induce the CEMF of the coils and cancel out the skin effect and not permit a charge build up - necessary for the "Streamer" discharge. Just my humble opinion.

nitrocrawler95 (author)2008-12-06

I have a question. To avoid hours of winding, couldn't you tape the roll of magnetic tape or just unwind the roll a little then tape it and cut the side off. Then all you would have to do is slide the wire off the roll.

dtphoto (author)2006-04-25

why not just attach a variable speed electric drill with sufficient torque to the tube (cut to final length) and speed up the winding process? You can get a 3" hole cutter and wedge in a few pieces of wood to fill the gaps. Put your wire spool on it's side in a box to prevent rolling away and then you can finish the coil in a fraction of the time.

chriskarr (author)dtphoto2008-11-01

I've tried this, and it can work, but the spacers really ruin it for you... If the form is PVC and too long, the support from the drill will cause the tube to warp and when this happens, it will go 'flop, flop, flop' with one 'flop' every revolution, and your coil will have a point, each revolution, at which it is nearly impossible to keep tension, and another where the tension is greater than expected and the possibility of a wire snap is greater than normal.

sueman2 (author)2008-10-21

how do you make a tesla coil?

TheMadScientist (author)2008-06-26

is it just me, or does anyone else here think the guy that made this said to himself... "hmm, I think that would make an AWESOME paper towel holder" and Now that I mention it.. PAPER TOWEL HOLDER OF ULTIMATE DOOM.

WudWar (author)2008-04-18

Check out the great free program from.

puffyfluff (author)WudWar2008-06-08

I use Tesla Map too, but if you just want a quick rough calculation, this is a good program for the basics. An online calculator that is also helpful (with a lot of general information too) is Deep Fried Neon.

WudWar (author)puffyfluff2008-06-12

Thanks a lot, those are both great tools that I've never seen before.

puffyfluff (author)WudWar2008-06-12

You're welcome.

SnuffyDaPenguin (author)2007-05-11

lol dunno where to get any really big capacitors. All I have is a TON of photo flash capacitors. My friend's dad is a dumpster diver, and he found like 7 crates of cameras. some of em leaked, but most of em are all right. Anyway, where can I get any bigger/better ones?

iq_abyss (author)SnuffyDaPenguin2008-02-08

My microwave HAD some fairly large capacitors in it--like 200-300 microferets or something. I don't really remember--big shock--mom threw the whole project out.

nak (author)iq_abyss2008-02-08

A new discovery!

puffyfluff (author)nak2008-06-08

That is really cool. I cracked up for an hour. Honestly! What program did you use?

nak (author)puffyfluff2008-06-09

Macromedia Fireworks, glad you liked it :)

puffyfluff (author)nak2008-06-09

Well, it is really funny.

iq_abyss (author)nak2008-02-10

Oops-that was supposed to be Microfarads--do forgive.

puffyfluff (author)iq_abyss2008-06-08

Don't worry. You are not the only one. My problem is a lot of calculation programs give you an output in microfarads and then want you to change it into picofarads. Sometimes I forget, and it ends up calculating like 0.001 turns. I freak out and then remeber, and feel like tomorrow mornings global headline will be "Master Science Geek Turned Into Scavenging Idiot". It happens all the time.

Grey_Wolfe (author)nak2008-02-16

That's great, where'd you find the pic. lol

nak (author)Grey_Wolfe2008-02-16

I made it from google image search images ;-P

pyro13 (author)SnuffyDaPenguin2007-11-01

Don't judge, because i know next to nothing about Tesla coils (even though i REALLY want to make one), but you can probably get a good sized capacitor out of an old TV.

SnuffyDaPenguin (author)pyro132007-11-02

Thanks, even though this is like...really really old. Note the post was in May...We already built the Tesla coil, something else went wrong, and we're gonna build a new one very soon. I don't happen to have any old TV's though either...Oh, wait. Yes, my friend's dad has a bunch of 5" black and white TVs that have no power cords, I guess I could use those...

Really! Awesome! How many? I'll pay for those.

pyro13 (author)SnuffyDaPenguin2007-11-02

yeah those would probably work. Sorry, I didn't read the date :$

I recomend building you own. try going to
that site is really useful. plus, building your own is a WHOLE LOT cheaper. but, try making small ones to to get the hang of it first.

robodud3 (author)2006-11-27

right so i need to make a coil too but i need to find a website where i can get the right numbers to make it work i plan in making the secondary coil only about 3-4 feet high and spend only about $50 for a transformer and the rest of the parts for $25 or so if any1 can hepl me it would be appreciated

puffyfluff (author)robodud32008-06-09

Oh, and another note-a two foot long secondary is about 1300 feet of 22 awg wire! It might be hard to find that for less than 25 bucks, and a variac might pose some financial problems too...

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