Re: Small Tesla Coil using disposable camera transformers
Mates, Thu Jan 03 2008, 11:36PM

It almost looks like cheating... I would never believe you can get so much from such a litle voltage and power...

BTW: I do not see any inverter feeding the transformers. Is it so small?

Re: Small Tesla Coil using disposable camera transformers
Capper, Fri Jan 04 2008, 01:18AM

I need one of those on my desk at work.

Re: Small Tesla Coil using disposable camera transformers
CT2, Fri Jan 04 2008, 07:46AM

The inverter is only that small resistor going from pin to pin and a transistor (on the side of the transformer I think).

Re: Small Tesla Coil using disposable camera transformers
Logan Kennedy, Sat Jan 12 2008, 04:35AM

That's pretty wicked!

What a kludge, but I'm amazed it works...

Show us some arc photos, or record a small movie. I've got to see this thing in operation. :D

Re: Small Tesla Coil using disposable camera transformers
J. Aaron Holmes, Sat Jan 12 2008, 04:58AM

He included a movie. Look again

Cheers,
Aaron, N7OE

Re: Small Tesla Coil using disposable camera transformers
Logan Kennedy, Sat Jan 12 2008, 05:07AM

OH I see it now, haha!!

Wow, it works, and it's halfway decent. Big surprise!

EDIT: What kind of drive time do you get from those AA batteries? You should probably get some lithium ions for better performance and current! It would also increase drive time drastically.

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Fri Feb 15 2008, 08:42AM

With my 850mAh AAA batteries it runs propably 5min. I have also some nice 2500mAh AA cells, I would've used them but I've currently got no holder for them.

Re: Small Tesla Coil using disposable camera transformers
uzzors2k, Fri Feb 15 2008, 01:28PM

Do you have some pictures, I can't get the movie to work.

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Fri Feb 15 2008, 04:33PM

Here's one frame captured and cropped from the video. Notice that the video was taken in a completely dark room and the camera was propably 1.5cm away from the breakout point. The camera was on ISO 400 setting!! The discharges are about 5 mm long.

Re: Small Tesla Coil using disposable camera transformers
Ultra7, Fri Feb 15 2008, 05:11PM

Wow, I wanna build one.
You got a parts list and Schematic?

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Sat Feb 16 2008, 12:30PM

Well the parts are really easy to get:
There are two disposable camera transformers with their inverter circuits. Then there is a 6-stage CW multiplier with a limiting resistor (IIRC it was 1M). Then the standard sgtc parts (cap, spark gap, sec and pri coil)

Re: Small Tesla Coil using disposable camera transformers
Urgentemente, Sat Mar 08 2008, 05:42PM

As a complete beginner having wanted to build a TC for a long time I'd love to start with something small like this, any chance you could post up a list of the specific parts (like what you used in the CW multiplier) and maybe a circuit diagram and a bit of a 'guide' to building it, what sort of wire, how many turns for the primary and secondary coils etc

sorry if that's tedious, but would love to have a go at building one of these !

Re: Small Tesla Coil using disposable camera transformers
CompWiz, Sat Mar 08 2008, 11:16PM

I was just at walmart and I asked there photo place for there used disposable cameras (they had a huge bin of them!)

but they said no...(yet another reason to hate walmart...)

but anyway this looks like a fun little project!

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Mon Mar 10 2008, 01:29PM


Glad to hear you like it. Now I have a comprehensive tutorial for this coil in progress


Go to a camera shop and ask nicely enough (or use the m4g1c w0rd "student"). You should be able to get some of them (I got twenty of them once now they know me quite well in the camera shop)

Re: Small Tesla Coil using disposable camera transformers
Urgentemente, Mon Mar 10 2008, 11:22PM

[quote]
Glad to hear you like it. Now I have a comprehensive tutorial for this coil in progress
[/quote]

Excellent spark, I look forward to it, seems like a great way to start out !

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Tue Mar 11 2008, 01:02PM


Hehe Don't except too much from this coil. Althogh with good tuning and many transformers you can get some better results. I didn't tune my coil too well.

Maybe why beginners prefer design like this is that they don't like to deal with anything dangerous.

Re: Small Tesla Coil using disposable camera transformers
Urgentemente, Tue Mar 11 2008, 04:12PM

Don't worry, I'm not expecting wrath of <insert major deity here> style lightning bolts, just something to start out with, get to grips with building (although I've read through the theory a bit I think it's going to make more sense when actually constructing the thing at the same time.), and yes, I think it's a bit less daunting to start with if it's not going to be throwing 12" long sparks my way

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Tue Mar 25 2008, 03:20PM

Now the tutorial is ready. Sorry it took a bit long Just didn't have time to make it.

Hopefully you understand the tutorial! I don't have any real pics (sorry for my Paint artwork)

Bjorn can think is it suitable for the wiki or not.

Re: Small Tesla Coil using disposable camera transformers
Urgentemente, Wed Mar 26 2008, 12:47AM

Nice one spark, I was just showing this page today to someone at work (he's soon to be doing a HV course for our workplace, lucky sod!).
I've downloaded the tutorial, and will be having a read through it over the next few days when I get some time to think straight!
thanks for preparing it.

EDIT:
Just read it, nice and short and seems easy enough to follow, I'll have to start getting the bits together to try building it.

Re: Small Tesla Coil using disposable camera transformers
teslaguy, Wed Mar 26 2008, 02:24AM

I dont quite understand how those transformers can be fed from two batteries with only a resistor connecting the pins? If you turn them on and off quickly thats one thing, but it seems to me that your not and i have no idea whats going on here.

Re: Small Tesla Coil using disposable camera transformers
..., Wed Mar 26 2008, 05:19AM

There is also a transistor connected to it. It works but having a feedback winding on the transformer that feeds the transistor causing the circuit to resonate.
Quite ingenious little drivers

Great coil BTW

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Fri Apr 11 2008, 01:06PM

Update, check the top post

Re: Small Tesla Coil using disposable camera transformers
Dr. Shark, Fri Apr 11 2008, 01:30PM

Slightly off-topic, however my guess on how the "inverter" works is that it's a blocking oscillator like the "Joule thief" here:
At least that's the only inverter circuit I know that works with only one transistor and one resistor, and I think a while back there was a thread here by someone who modified the circuit for 400V output - possibly even using a disposable camera transformer.

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Fri Apr 11 2008, 01:35PM

Yep, it's a blocking oscillator.
The camera circuits can be overdriven up to 6 volts so in theory you could get 1.2kV out. The highest voltage I've gotten would be kinda 500V (driven from 3 volts)

Re: Small Tesla Coil using disposable camera transformers
Arcstarter, Fri Apr 11 2008, 04:19PM

This is absolutely amazing! I cant get video to work though. The thing that is amazing is that someone could actually get a spark at all with just 4.5 watts. That was a seriously...Well it was ingenious. Now make a tiny rsg( even though it will probably reduce performance).

Re: Small Tesla Coil using disposable camera transformers
ShawnLG, Sat Apr 12 2008, 06:20AM

"This is absolutely amazing! I cant get video to work though. The thing that is amazing is that someone could actually get a spark at all with just 4.5 watts. That was a seriously...Well it was ingenious. Now make a tiny rsg( even though it will probably reduce performance)."

I have made a small RSG coil last year but I did not used a camera flash inverter. An air ionizer inverter was used.

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Sat Apr 12 2008, 07:11AM

Sorry about the video, I messed something up with ffmpeg... Now it's WMV, you should be now able to view it.

ShawnLG:
This coil wasn't properly tuned. I'll rebuild it and tune it so it'll hopefully work alot better

Re: Small Tesla Coil using disposable camera transformers
lpfthings, Sat Apr 12 2008, 12:17PM

Thats amazing!!! never knew camera transformers could be used for such a thing, and with the relativly low voltage, caps wouldnt cost to much either. Nice work!

Re: Small Tesla Coil using disposable camera transformers
Dr. Shark, Sun Apr 13 2008, 03:04PM

Spark, (hey, yet another Fin in the forum!), would you be able to give some more information about the camera transformer? I don't have any disposable cameras so I tried winding my own. I used a tiny 25mm^2 ferrite core with 5+5 windings on the primary and a few 100 windings on the secondary. I could get it to oscillate alright, but even from a 5V supply it took several seconds to charge a 1uF cap up to 300V, and it oscillated at a very high frequency (about 200kHz).

If you have more info on your transformer, I could try to replicate it.

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Mon Apr 14 2008, 10:12AM

First, it should be really easy to get disposable cameras (I prefer Fujifilm; they have got simpler circuit that kodaks for example)

I took a look at my transformers. They seem to have a single ~4 turn primary, so good guess for secondary turns could be ~800 turns (really thin wire <0.1mm)

Take a look at that circuit and you will notice that the feedback winding is in series with the secondary. It's a little different from the joule thief circuit.

Re: Small Tesla Coil using disposable camera transformers
Chris Cristini, Tue Oct 14 2008, 04:37PM

That is cool maybe make the secondary smaller by using a Bic pen tube and build a cool case might be something u could sell to beginners.

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Wed Oct 15 2008, 07:17AM

Yep, I have been planning to make a revision of this little coil. I've been thinking to run it of a 9V rechargeable, but haven't yet managed to get a suitable ferrite core to wind my own transformer.

Re: Small Tesla Coil using disposable camera transformers
Firefox, Wed Oct 15 2008, 09:32PM

The transformers from old computer PSUs work well, Uzzors and several others have wound flybacks on them. Also, any electronic device you find likely has one in it. Most CRT TVs and monitors have at least one or two, along with the main flyback, and I've found a few monitors with five or six small transformers in them.

Re: Small Tesla Coil using disposable camera transformers
Chris Cristini, Thu Oct 16 2008, 03:46PM

yea me to there is endless possibility's when it comes to TV,s and transformers.

Re: Small Tesla Coil using disposable camera transformers
Firefox, Sat Oct 18 2008, 03:43AM

By the way, Dr. 2N3055, I never posted this, but my first TC was based off your design, using instead a D cell battery and a 22 stage CW multiplier with a 1nF home rolled overhead cap. It worked excellently, giving off up to a 1 inch streamer and about 3-4" of corona. I could fill a light bulb with streamers. Secondary ended up with an Fres of about 2MHz.

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Sat Oct 18 2008, 02:03PM

Nice! Do you have any pics, you could post them here! Let's see what kind of results I will get from the revised coil (not coming very soon.)

Re: Small Tesla Coil using disposable camera transformers
Firefox, Sun Oct 19 2008, 06:59AM

I will get those pictures for you... eventually, Dr. Unfortunently, the PSU has since gone south for the winter (I need to replace four burned out diodes), the cap has died, and the coil is at home, while I am at college. While I can certainly get the cap built and PSU repaired, I will have to wait until thanksgiving break to repair the coil itself. I also, believe it or not, got those results with PVC coated 26 gauge wire, 266 turns on a 1.5"*9" former if I recall correctly.

Re: Small Tesla Coil using disposable camera transformers
fatboyslim, Sat Oct 25 2008, 11:15AM

What happens if your camera circuit has two diodes. Which one do you take off and can you include a schematic to how you wired it. And also do i just connect only one wire on the circuit as the 660volt line. Also is the 660volts from only one circuit or two. Im really eager to build this and im just a bit confused. Ive built a larger tesla coil before and have always wanted to make a small battery one which can sit on my desk. Help would be much appreciated

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Sat Oct 25 2008, 02:37PM

The diode you take off should be the one which has one end connected to the main transformer (the bigger one). Yes, the '660V line' is only one wire, as the voltage is generated against ground. The 660 volts is from one circuit as I drove it from 3V instead of 1.5V.

Sorry, the tutorial really is a bit confusing, as I look at it afterwards. Basically the thing you want to do is just to find the high voltage AC output from the transformer. This can be found by locating the diode which has its other end connected to the transformer. The point where it connects to the transformer is your HV out, just remember to remove the diode! Then build a Cockroft Walton multiplier as shown here and connect your HV out and the ground to it. Remember to put a limiting resistor to the CW output. The rest is just like building any DC Tesla Coil.

Re: Small Tesla Coil using disposable camera transformers
Dragon64, Sat Oct 25 2008, 08:13PM

What do you think is the estimated price for all the component?

Re: Small Tesla Coil using disposable camera transformers
fatboyslim, Sun Oct 26 2008, 12:33AM

Do you also remove the big capacitor as well

And the diodes you use for the multiplier is that the ones you remove from the circuit. Also do you have to solder a wire to the metal push switch to keep it running?

Sorry for all these questions, but what happens if the diode connecting to the transformer is not on the grey strip. iE the The other side. The transformer does not connect to the grey strip side but the other side of the diode

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Sun Oct 26 2008, 10:31AM

I'd say 5-10$ depending on where you get your caps and diodes for the multiplier. I got mine from used disposable cameras, but you'll have to get many of them.
You can remove it, however it doesn't matter as it's already isolated from the charging circuit as the diode is removed.
Yes, you'll have to get many of those camera flash boards.
Yes, I forgot to add it to the tutorial.
It's ok, your circuit has positive output as some other circuits have negative output. However, it doesn't matter on this circuit. Do as told on the tutorial.

Oh, and please avoid double posting. It's against the forum rules.

Heck, I'm very surprised by the popularity of this little circuit. Maybe I should seriously think of making a revision of the tutorial. And a brand new coil, too! But it's very hard to make a one-for-all tutorial as there are many different types of camera flash circuits.

Re: Small Tesla Coil using disposable camera transformers
Zenador, Sun Oct 26 2008, 12:34PM

Why are you supprised? This is a fantastic "mini" project. I built a 10" SGTC, and it works very well. I just can't take it to work. Enter the "micro" SGTC from camera parts. I got 33 used cameras from a photo place and am in the process of building 2 little ones, with some modifications.

I'm putting everything in a "project box", adding a 2P2T switch, and a 3.3v 500ma wallwart. I can use the batteries or wallwart. I just don't want to eat dozens of batteries demo-ing the TC.

In your original photos, you had completly disassembled the boards, and were only using the parts needed. Do you have a schematic of that setup? Even with the diode removed from the HV lead on the xfmr, there is still power being leached into the rest of the board (evident with the LED lighting up)

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Sun Oct 26 2008, 12:58PM

There are many types of disposable camera flash boards, mine were from blue Fujifilm cameras. Here is a schematic which most closely represents the circuit in those ones. Just look at the leftmost parts (not including the diode) and you'll figure it out. It's just the transformer, resistor and transistor. For different types of boards, a Google search for "disposable camera schematic" will return many different pages with different schematics. They seem to vary brand by brand, but I've even seen two different Fujifilm ones! If you still can't find a suitable schematic, you must do a bit 'reverse-engineering' to figure out the parts and the schematic which are driving the transformer.

One important note to anyone who is going to build this:
Use commercial capacitors!
Homemade caps just leak out the tiny bit of power coming from the little transformers.

Re: Small Tesla Coil using disposable camera transformers
Zenador, Mon Oct 27 2008, 05:59PM

So I finished my "micro" SGTC yesterday. This is the first or many (family/friends are asking for one now...)

I have to say, well done Dr. 2N3055 on your descriptions for building this little guy. I think the biggest pain in the build was the CW multiplier - those little caps just do not want to sit still to solder them together...

changes and results...

6 turns 1mm wire
120mm x 15mm secondary (32AWG magnet wire) (former was the tube you get solder in)
Three 1"x1/16" aluminum crush washers soldered together to make a top load.
Two 2kV 300pF MMC (parallel - series made it worse)
1.5mm spark gap.

I get about 4mm discharges, and continuous arcs just about an inch. The arcs are visible in a lighted room, which was important to me - I had to demo it at my desk at work today...

If you have any other uses for those flash boards, post them up, I have another 30 I can play with....

Z

Re: Small Tesla Coil using disposable camera transformers
fatboyslim, Tue Oct 28 2008, 03:23AM

Hay, sorry for double posting. I just got my camera circuit and i got 1386 volts from ONE BATTERY! When i wired the CW multiplier and attached it to the camera circuit nothing happened. Is this because my camera circuit needs a negative multiplier instead of a positive one. The one shown in your tutorial is a positive multiplier according to Ive hit a wall right now and im unsure what to do. Could the problem be with my multiplier. The diodes i used are from the kodak circuit which are IF16 diodes. Should i use UF4007 or can i use IN4007 instead?

Re: Small Tesla Coil using disposable camera transformers
Zenador, Tue Oct 28 2008, 02:19PM

Fatboyslim - Where did you measure the voltage? 1.3kV is too high (IMO) from the big xfmr. That make more sense from the secondary (smaller) xfmr. The smaller one is connected to the copper plate behind the flash bulb to ionize the gas.

From one AA or AAA battery, the larger xfmr should output ~300V. I have 33 disposable flash boards, and they all read roughly the same.

Your board is generating +HV from the large xfmr based on your description of the diode in relation to the outputs. Same as most of mine. Remove the diode completely from the board. The side where the gray stripe was is negative (common) - wire it to the common (-)(GND) of the CW, batteries, everything common. The non-striped side (connected to the large xfmr on the PCB) is the +HV which is wired to the + on the CW.

In my build, all common wires are really common, battery, xfmr, CW, SG, they are all connected. If the common on the CW is NOT connected to the negative (common) of everything else, it still works, just very very slowly. The SG fires only twice a second, so the oscillation is to slow to do anything useful. Properly wired, it works just like a full sized TC, just on a small scale.

Re: Small Tesla Coil using disposable camera transformers
fatboyslim, Wed Oct 29 2008, 02:26AM

the second pin from the 3 pin side of the transformer connects on to the grey side of the diode. I removed the diode and soldered a wire to the grey strip side. I measured the voltage from the wire and the negative side of the battery. This gave me the 1.3kv. Where should i read the voltage from? Do i have to have two wires from where the diode used to be? and that is my negative and my positive. I am currently using a fujifilm circuit.

Re: Small Tesla Coil using disposable camera transformers
Zenador, Wed Oct 29 2008, 01:32PM

Ok, Grey side of the diode to the xfmr is negative HV out.

Voltage should be measured from xfmr to positive terminal of the battery (I think) on your board.

Black wire to the grey side where the diode used to be, red wire to the other hole. The CW Multiplier also needs to be built correctly. There are positive CW-M and negative CW-M. Difference is diode direction.

Re: Small Tesla Coil using disposable camera transformers
fatboyslim, Wed Oct 29 2008, 09:48PM

So i will need to build a negative Multiplier. Is that correct. I measured the voltage again. Im getting 230 volts cause my battery is kinda low.

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Thu Oct 30 2008, 03:42PM

Very nice! Could you post any pictures of it to this thread? I'd love to see your coil.
What value did you use for the limiting resistor? You seem to have found the optimum value or at least close to it.

Your imagination is the limit when it comes to camera flash boards. Some ideas:
-a miniature ion spray gun
-a cap bank to power coilguns and railguns, for example

Then you could make a big CW with pulse rated diodes and capacitors and amaze people by generating loud 1-inch long fat sparks from a 1.5V battery

CT2 built a setup like this Tesla coil, but instead of the air-cored transformer he used a flyback and generated kinda long arcs. I actually got the idea for my coil from CT2!

Re: Small Tesla Coil using disposable camera transformers
Zenador, Thu Oct 30 2008, 04:19PM


Limiting resistor? What limiting resistor?! Lol.

I tested with everything from 68R to 10M. 1/4W, 1/2W, 1W. The higher the resistance, the smaller the output. All my wiring is 22AWG stranded for connections, 18AWG solid primary (8 turns, tapped at turn 6) 32AWG magnet wire secondary.

I get about 8-10 minutes of runtime on 4AA batteries, have gone through 4 sets of batteries (free from cameras ) and without the resistor, works like a beauty. I'm at work and don't have any pics here, but I'll post them tonight when I get home.

I tried to get more creative with the second one (building for my brother.) I reverse engineered several boards and drew out the plans, and built everything on one board. Boo-Urns - I failed. Going to attempt more trouble shooting tonight. Essentially everything is contained on a 2"x3" PCB (non-etched) except the batteries and the switch. The board is attached...

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Thu Oct 30 2008, 05:35PM

I didn't see the resistors for the transformers. Did you remember adding them? They're needed to start the oscillation.
Other than that, very nicely done. Just watch out for arcovers under the board!

Re: Small Tesla Coil using disposable camera transformers
Zenador, Thu Oct 30 2008, 05:59PM


Yes, I added them. That image was taken at work (slow day yesterday) and I added them after the fact. Didn't help though... I just spent my lunch-hour going to photo stores near my office getting another 30 cameras... gotta love free parts.

Re: Small Tesla Coil using disposable camera transformers
fatboyslim, Fri Oct 31 2008, 07:57AM

Hi, i wired up a three stage multipler to the circuit and it managed to work i got 600-700 volts. All of a sudden it stopped working and would not create the sparks it was creating before. I then wired up a 6 stage one to see if it would make a difference but nada. My multipler is a negative multipler and the grey side of the diode (which has been removed) side is connected to in voltage in. and the other side is connected to the ground. Does anyone know what im doing wrong. Im using only one circuit on 1 AA battery. The circuit works fine but it doesnt work when connected to the multiplier. My diodes are 1F16 diodes and the capacitors i used are two different types. The grey and yellow one. Mind you it was working when i wired a three stage with one grey and 5 yellows.

Re: Small Tesla Coil using disposable camera transformers
Zenador, Fri Oct 31 2008, 01:18PM


My working coil uses both the yellow and gray caps. Just make sure they are rated the same. Mine are all marked 223k400. The diodes are OK, I mixed 1F16's, F15V25's and F15V33's on my 6 stage CW. With no load, you should hear that unmistakable sound from the flash board, and get a measured voltage of ~-300V. My board, using 3V (4.5VA) I read an output of ~700V. Just don't do what I did - I dropped one of my test leads for my DMM and is landed on the spark gap. A 600V rated DMM REALLY doesn't like 2000V.

I'd check the caps and diodes in your multiplier. If any of them were arcing, they may be toast. If you could post pics (close-up and clear) we may be able to see any issues...

Re: Small Tesla Coil using disposable camera transformers
fatboyslim, Fri Oct 31 2008, 08:25PM

I did hear some arcing before. I think my caps may be toast cause sometimes when i connect the multipler no noise is heard from the board and when i use 3 volts on my board the spark is EXTREMELY LOW. like only 115 volts for some reason. I think ill change my camera circuit. This ones giving mee too much trouble. How can you tell if your caps are fried?

Re: Small Tesla Coil using disposable camera transformers
Zenador, Fri Oct 31 2008, 10:32PM


Some DMM's specifically have Cap testing modes, I was looking at one today. Testing can be done 2 ways. If your DMM supports 1000V AND you have a HV probe, run the circuit, break the connection from CW HV out to GND, turn the board off, measure voltages across each cap, starting from the HV input, or just run the circuit with the HV probe and common probe in series from CW HV out and GND. I can't be responsible if you fry your DMM. Fastest way would be skip testing with the DMM and just short out the CW. It should arc and discharge BEFORE you actually touch the HV out and GND. 1kV per mm.

Re: Small Tesla Coil using disposable camera transformers
Zenador, Fri Oct 31 2008, 10:52PM

As promised... The pics of the little guy... The switch on the side is 2P2T, 1T is batteries, 1T is the Blue/Yellow jacks. I have a 5V/3A 3point power supply for that. The spark image is top-load to grounding (bottom of secondary soldered to 12AWG copper) and is about 1".

Z

Re: Small Tesla Coil using disposable camera transformers
Voltwad, Sun Dec 07 2008, 01:32AM

This looks awesome. I just got a handful of cameras tonight and I'm gonna start making this tomorrow. I'm wondering what I could do with the flash tubes though. I wonder if they could be used in place of the spark gap with the tickler driven by a 555 or something. My intuition tells me they would be rather inefficient, converting most of the energy into light. Has anyone tried to use a discharge tube as a spark gap for a TC or a marx?

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Mon Dec 08 2008, 02:02PM

I've actually tried using the flash tube as a trigger in a coil gun, and that is a very bad idea because most of the power is converted to light. So don't use flash tubes as spark gaps!

Re: Small Tesla Coil using disposable camera transformers
Zenador, Mon Dec 08 2008, 02:29PM

The only good use I have found so far for the 20+ flash tubes I have is lighting them up from the TC. Streamers from the small coil are almost impossible to see in a lit room, arcs from the top load to secondary ground are visible but "weak."

Solder one or two bulbs to a wire, and hold it close to the TC when it running. It acts as a plasma globe. The small coil is also capable of lighting up CFL's.

Re: Small Tesla Coil using disposable camera transformers
Voltwad, Thu Dec 11 2008, 06:44AM

Alright, I've already knocked together a prototype and then taken it apart to try and make it more powerful. I got about a 1cm spark and my mouse and CD drive started freaking out. :) Anyway, I thought I'd share this circuit I worked up. I don't know how others with multiple transformers are connecting their outputs but I figured out I could drive one of the two xfrmers I have backwards and tie the transistor bases together to get two opposite synchronized pulses. Now I can power a fullwave CW generator.





Here's the circuit.





Here's a trace of each HV terminal. The peak of each terminal is between +8 and +10 hundred volts and the ringdown is about -six or -seven hundred.





Here's the voltage between the terminals. Peak is about 14 or 15 hundred volts and ringdown is about 11 hundred.

Re: Small Tesla Coil using disposable camera transformers
Zenador, Thu Dec 11 2008, 02:00PM

The power supply on the schematic looks like it says 1.5V? I drive my 2 xfmr board with 3V (2 AA batteries) to each xfmr, or from a 5-7V bench supply to both xfms, toggled by a 2P2T switch. I'm thinking of building a quad setup, and using higher voltage transistors to run at 12V. 12V to the transistors from the flash boards just blow and start a fire.

How many stages are in your CW?

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Thu Dec 11 2008, 02:19PM

I should note that the insulations of the transformers are not made to stand 12V use, because the secondary voltage will be also significantly higher. But feel free to try, it might work if you're lucky!

Re: Small Tesla Coil using disposable camera transformers
Voltwad, Thu Dec 18 2008, 12:14AM

Awright, my mini camera TC mark II is now finished.





The secondary is 1" dia. x 3.5" h. wound with 30 awg. The topload is blue styrofoam cut and sanded and then covered with aluminum tape. After I put everything in the box, the characteristics of the coil changed so much that I had to add a few more coils to the primary to get it to ring properly. I also added a disc of brass mesh over the topload from which hangs a ground wire to increase the secondary capacitance.





Here's the insides. 2 flash inverters, one positive one negative. A 7 stage fullwave CW generator made with 1KV diodes and 2KV 1 nano caps. A gap made from some small brass nuts and bolts with copper wires soldered on. And the tank cap is two 2.5 nano 10KV CeraMite caps seriesed for 1.25 nano. The battery pack was rewired to parallel the two batteries so I can run it off only one if I want. There's no difference in power throughput using two, only the run time. I could series the batteries but I don't want to overwork the transistor or the transformer secondary. Also the CW is probably being pushed to the limit as it is.





And this is my pathetic attempt at capturing the spark. It's about 15mm spark distance which is probably pretty good for one AA battery yes? My poor digicam just couldn't get a very good still image, let alone video but it looks good running on my desk top.

Re: Small Tesla Coil using disposable camera transformers
Arcstarter, Thu Dec 18 2008, 01:16AM

If that is metal under the top lid thing, that might be reducing the performance. It acts as a shorted turn, and much of the power would be used in eddy currents in the metal.

Re: Small Tesla Coil using disposable camera transformers
Weston, Thu Dec 18 2008, 03:20AM

Voltwad: Cool coil. Is that a bread board? breadboards are not good for high voltage, they can arc over internally.

Re: Small Tesla Coil using disposable camera transformers
..., Thu Dec 18 2008, 03:55AM

I don't think that brass plate will give you too much trouble. For good conductors that act more as a reflector than a shorted turn, although that helical coil is definitely coupling a bit of energy into the plate. If its enough to make a difference is hard to say.


Also, you might want to consider moving the power supply over a piece of protobord instead of a breadbord. You can get pieces with the same pattern so you can make it exactly the same, and then your breadboard will be free It will also be less likley to short out or go open circuit to boot

BTW my aa powered sparker get 2.5cm

Re: Small Tesla Coil using disposable camera transformers
Voltwad, Thu Dec 18 2008, 06:51AM

Yeah, the brass is supposed to act as a ground plane. Because this is a battery powered coil, there's not any connection to the real world ground and without any ground plane the secondary capacitance is way too low. I suppose I could improve the energy characteristics by cutting a circle or some slits in the plane underneath the coil itself if I do another revision. As far as the breadboard goes, I haven't seen any problems on the HV side of the CW generator. The gap only fires at about 1.5 to 2 mm or less and I think the breadboard plastic has been handling that voltage pretty well. I think in the near future I might get some more cameras or possibly wind my own boost transformers for a 5 or 9 volt supply and get some custom PCBs made. Incidentally, I did a preliminary search for 'smallest tesla' hoping to find a thread for a smallest tesla coil competition and didn't see one. Has anyone seen anything like this around?

Re: Small Tesla Coil using disposable camera transformers
..., Thu Dec 18 2008, 07:09AM

smallest sstc:



smallest vttc



smallest sgtc i know of



although if you don't count the driver electronics, this one might have it beat


There were also a few small sgtc's made last year sometime, but I don't think any of them beat the linked coils.

edit - fixed vttc link

Re: Small Tesla Coil using disposable camera transformers
Myke, Thu Dec 18 2008, 07:34AM

Your smallest VTTC link doesn't go to ShaunLG's VTTC :P

Re: Small Tesla Coil using disposable camera transformers
Jamil merali, Sat Jan 24 2009, 08:16PM

why do you need the resistor at the end of the voltage multiplier.

Re: Small Tesla Coil using disposable camera transformers
Killa-X, Sat Jan 24 2009, 08:57PM

I need to learn how to make a tesla coil.. I got an ignition coil, and over 50 camera circuits (5 in parallel on my coilgun) :(

Can I just wrap many layers of 24 guage magnet wire around a PVC 1-inch pipe for the 2nd coil? Or isnt it magnetic coil?

I'm kinda new to em xD

Re: Small Tesla Coil using disposable camera transformers
Myke, Sun Jan 25 2009, 01:33AM

So that the caps don't discharge into the load all at once. Also the more you load the multiplier, the less voltage you get out.

Re: Small Tesla Coil using disposable camera transformers
Tesla C, Mon Jan 26 2009, 06:28AM

On your tutorial which cap are you referring to when you say the 1nF@600V on the flash board? I think your talking about the little grey or sometimes yellow ones, Am I right?

Re: Small Tesla Coil using disposable camera transformers
Myke, Mon Jan 26 2009, 07:37AM

I think those are usually 22-33nF 330V caps, right?

Re: Small Tesla Coil using disposable camera transformers
Tesla C, Mon Jan 26 2009, 02:10PM

Well the flash caps are rated at 330 and somewhere around 120µF. But as for the silver ones which can be seen in the picture i'am not sure what they are rated at. But maybe someone else can tell us what they are rated at.

Re: Small Tesla Coil using disposable camera transformers
Zenador, Mon Jan 26 2009, 02:47PM


The large flash caps are 300V to 330V, and 120uF to 160uF. The caps in the multiplier (yellow or silver) are 1nF @ 200V, or 1nF @ 400V (I have seen both the 200V and 400V varieties.) and are easily damaged. Excessive heat (from de-soldering and re-soldering) has caused breakdowns between the layers, which can then be seen arcing internally.

I couldn't find my specific part numbers online, so I took one to my electronics shop, found an equivalent cap (by package) and compared the identification. They are most likely identified like 103k200 which breaks down as (iirc):

1 = (capacitance in nF)
03 = multiplier factor
k = ?
200 = voltage

Z

Re: Small Tesla Coil using disposable camera transformers
Tesla C, Mon Jan 26 2009, 05:32PM

Yeah I saw the ratings on the silver or yellow ones with ratings like that and didn't under stand what they meant by it, so thanks for sharing that information. Although what that K means being unknown hopefully it doesn't matter much.

Re: Small Tesla Coil using disposable camera transformers
MRacerxdl, Tue Jan 27 2009, 01:51PM

103 => 10 and 3 zeros pF so: 10.000pF or 10nF

Re: Small Tesla Coil using disposable camera transformers
Killa-X, Wed Jan 28 2009, 03:55AM

I just hooked only 8 capacitors on the multiplier, and when i turned it on, i got a lot of hissing near the ground due to ions, but eventually it stoped working. Cut off a few diodes and caps, and worked again, and then stopped. Is there any thing im doing wrong here besdies touching leads to the grounds to make it snap?

Re: Small Tesla Coil using disposable camera transformers
Myke, Wed Jan 28 2009, 06:26AM

It seems like there isn't a resistor in series with the output because of the snapping when you make it discharge to ground. The discharge's peak current might be exceeding the peak current of the diodes causing them to fail.

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Wed Jan 28 2009, 07:16AM

That's very likely the case. It has happened to me more than once.
Use a limiting resistor if you want to keep your multiplier alive!

Re: Small Tesla Coil using disposable camera transformers
Jamil merali, Tue Feb 10 2009, 03:30PM

could i use this as a power supply

whats the easiest way to wind a coil

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Tue Feb 10 2009, 03:38PM

I suppose it would work, I don't know how much output current will it be able to supply. Still, getting some used disposable cameras shouldn't be too much trouble.
For coils of this size I suggest just holding the former in your one hand and the wire in the other. Start turning the former with one hand and guide the wire with the other. That's how I wound my coil.

Re: Small Tesla Coil using disposable camera transformers
Duality, Thu Feb 19 2009, 02:40PM

For coils of this size I suggest just holding the former in your one hand and the wire in the other. Start turning the former with one hand and guide the wire with the other. That's how I wound my coil.

that is how i wind all of my coils :P

EDIT:
is it possible to use your own build charge cap for the tesla circuit?
anny ideas about why my cascade does not work?
anny point's i can check?

Re: Small Tesla Coil using disposable camera transformers
Arcstarter, Fri Feb 20 2009, 12:40AM

I don't think that would work. It seems that it is a piezoelectric 'thing'. it puts out no real current, and i am sure that no matter how small our cap (within reason) it would not be able to charge it fast enough.

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Fri Feb 20 2009, 12:16PM

I think those little negative ion generators are based on small 'flyback-like' ferrite core transformers, just like disposable camera flashes are. But still, the one sold by Goldmine is said to draw only 50mA at 12V. That makes only 0,6VA and I suppose that is not enough. However it could possibly draw more current when under load. I might be wrong, though. Better to go with at least two disposable camera transformers. Better yet, try finding a bigger ferrite core and wind your own flyback transformer. Then you could drive it with a 555+MOSFET driver.

BTW, I've got a crazy idea. What about building a small ZVS flyback driver with two BS170 and power a disposable camera transformer with that thing? (with replaced primary, of course)

Re: Small Tesla Coil using disposable camera transformers
audio:deviant, Thu Jan 07 2010, 04:59PM

hello all, this little project has got me wanting to build one. ive been trying to locate some camera transformers with minimal luck. boots dont give them out and the local camera place closed down not long ago. would something like this do it
what are the transformers voltage out?

secondary is constructed just about to get started on the electrics just cant find a damn used disposable camera!

Re: Small Tesla Coil using disposable camera transformers
Bennem, Thu Jan 07 2010, 05:42PM

Hi James,

I beleive the transformers in your link are just pulse 2:1:1 ratio transformers,
they are designed for switching thyristors and triacs,
i used them in my solid state variac.
see if jessops have any old discarded disposable cameras they are
willing to let you have?

All the best,
Mel

Re: Small Tesla Coil using disposable camera transformers
audio:deviant, Fri Jan 08 2010, 10:49PM


alright mel how do.. i just bought some cheap ones in the end! just waiting for some caps and diodes now! was just wondering what the coil part that connects to the flash is? i presume i dont need this?

how do i link the two flash boards? sorry i cant see how that bit works.. in that first picture are the transistors glued to the transformers? cant seem them in that pic.

cheers

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Sun Jan 10 2010, 04:24PM

If you mean the tiny transformer thing (the smaller one), it isn't needed. It's a trigger transformer which is used to create a high voltage (like thousand of volts) to ionise the gas in the flash tube to trigger the flash.

In fact when I built the circuit, I did a bit of reverse-engineering to figure out what parts are needed for the flyback circuit to work. In this case they were the transformer, a resistor, a transistor and a diode for rectification. Then I desoldered the components and rebuilt the circuit to get it a compact as possible. The transistors are just hanging on the sides of the transformers.

Re: Small Tesla Coil using disposable camera transformers
audio:deviant, Wed Jan 13 2010, 06:01PM

yeah ive been working on a bit of reverse engineering! looks much better when its smaller.

ive just been trying to get the thing working, managed to get a good arc over the spark gap about 1.5mm for now i hooked up a cap 0.33uf 2000v its a 42l3332 cap. the arc across the gap disappeared and then let off one massive bang! and one of the transistors got massively hot.. what could be causing this? tuning?

also what should the secondary be grounded to?

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Mon Jan 18 2010, 07:09PM

Most likely the cap is just too big. It takes a while for the transformers to charge the cap and then it discharges with a loud bang. I used a 1nF cap which is 330 times smaller than yours. A discharged cap is like a dead short, so maybe that's why your transistor is getting hot.
I didn't ground my secondary anywhere.

As a conclusion, read carefully through this thread and see what other people have done. Zenador and Voltwad built similar little coils and uploaded some pics of them here too. You may also want to study some theory about general electronics and Tesla cois.

I wrote the "tutorial" (link on the first page) two years ago (I was 13 back then) so it may be a little... childish. But it still has some useful information. And, as already said, look at the other people's work shown in this thread. My coil was originally just built of some scrap/leftover parts, and it was quite a sketchy one after all.

I'm not an active electronics hobbyist at all nowadays, and my knowledge about electronics is limited. Also I haven't had the coil assembled for a long time, but I'll try to give the best help I can.

P.S. Google and HvWiki will be your friends in many cases too.

Re: Small Tesla Coil using disposable camera transformers
audio:deviant, Mon Jan 18 2010, 11:52PM

sorry i should have posted a reply saying i got the thing working just using one transformer. managed to find a few smaller caps. and a massive primary! still needs a bit of tinkering. the transistor was getting hot due to problems with linking multiple transformers been struggling with this one! made this circuit (cheers Voltwad) with no luck. and had a look at a couple of the other project pictures but its not that clear. Looking at a 2 or 4 transformer set up. i dont know if im being weird on this one but i cant seem to get it working, very annoying.

voltwad is it noticeably more effective having a full way CW?

mod edit oversized images


thanks for the tutorial and project idea dr! think i had less problems with my drsstc!

thanks again

Re: Small Tesla Coil using disposable camera transformers
Voltwad, Thu Jan 28 2010, 05:49AM

Hm, Well, I never actually tried paralleling two transformers on a 1/2 wave cw. I figured inverting one was a novel way to do it because if the transformers aren't perfectly matched, some of the energy from one will wash through the other and vice versa if they're paralleled. And these are supposed to be cheap, disposable circuits after all. If you got it working with one transformer and a 1/2 wave then try hooking up your coil. Bring the coil ground to the load and see if you get any nice arcs. Also, if you can post any schema, that will help in debugging.

Re: Small Tesla Coil using disposable camera transformers
Gunboat, Wed Feb 03 2010, 01:17PM

This is "Great!" I wish that more people would post about mini's.I try to educate people about Tesla and his coils,you would be suprised how many people don't know anything about this.I like it because it is portable.
thank you very much

Re: Small Tesla Coil using disposable camera transformers
audio:deviant, Wed Feb 03 2010, 10:41PM


right ive got a max of round about 1/2 cm of action at the moment. this is running one xfmr at 3v the secondary is pretty small as you can see in the pic its made out of a pen. using half cw 6 stage 1nf 1kv caps. the cap bank is a 2 1nf 2kv. iv grounded the secondary to the cap bank actually made quite a big difference. im going to mess with the tuning a bit more but it seems to be at its optimum.

i do seem to be having problems with the limiting resistor at the end of the cw arcing over. its a resistor from the flash board 1.5m

have you got a full schematic of your set up? voltwad. i would like to use 2 xfmr's or at least get some bigger arcs! how do i link them up in parallel otherwise?

formatted my comp lately so i havent got anything to draw a schematic at the moment.

Re: Small Tesla Coil using disposable camera transformers
Michalis.Biochem, Wed Oct 20 2010, 07:44PM

Hello, i just became a member of this forum.
Is the schematic of the tesla coil depicted first on this thread available?
If so, i would like to take a look because i couldn't make a whole circuit schematic from the attached pdf.
Thank you very much!

P.S any tips/advices are welcome because i am new in the field of electronics : )

Re: Small Tesla Coil using disposable camera transformers
Zack, Mon Jan 31 2011, 09:52PM

That's so cool! I downloaded the pdf for flash camera spark gap tesla coil and I tried building it. It only gave me a 2mm discharge, but I ran it on a single AA battery. It seems like all the HV people I see on the internet are on this forum.

Re: Small Tesla Coil using disposable camera transformers
Michalis.Biochem, Sat Feb 26 2011, 06:03AM


Try running it from 2 batteries. Also add more turns, like 6 for primary(3cm radius) and 600 for secondary(2cm radius). Mine puts out about 3cm arcs and can dimmly light a cfl.

Re: Small Tesla Coil using disposable camera transformers
MasterSoro, Tue May 17 2011, 03:27PM

i built the cockroft walton multiplier the way you said. i think i am getting 300V AC out of my flash board like you said. when i connect it to the CW and i mesure between out put and ground with one stage i get 600V pulsating DC which is what i expected. then i and a second stage and mesure between output and ground i still get 600V. and the same with 3 stages. iv tried with 6000V 470 pf( products_id=1620692), 3000V 330pf( products_id=1619903) 2000V 470 pf( products_id=1619883) and 500V caps. with 1000V diode.

Please help me

Re: Small Tesla Coil using disposable camera transformers
H8erade, Wed Jun 29 2011, 10:19PM

I was looking through this thread and I saw mentions of a .pdf tutorial... but I can't find any link. Am I missing something?

Edit:
Never mind. I found it with a quick Google search.

Re: Small Tesla Coil using disposable camera transformers
teslaozone, Fri Aug 05 2011, 09:43PM

Hello, does anyone know if you can just use a simple wall adaptor instead of batteries so it can run as long as you want without having to replace the batteries every few minutes?

Re: Small Tesla Coil using disposable camera transformers
Arcstarter, Fri Aug 05 2011, 10:21PM

Yes that would work fine.

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Sat Aug 06 2011, 01:02PM

Yep, I suppose it'll work fine. Don't go much above 3V to avoid breaking the tiny transformer or the drive circuit.

I haven't been even lurking around here for about a year or so. :o

Re: Small Tesla Coil using disposable camera transformers
teslaozone, Sat Aug 06 2011, 08:18PM

what is the max amps i should have in a wall adaptor?
I tried a 5v 2a adaptor. And, i got a nice little explosion...

Also, i tried running a 9 volt battery on only one flash board and i got about 1" arc, although the transistor on the flashboard quickly over heated and died. Is there any way of over running this circuit but heat sinking the transistor? It seemed to be the only problem when running with a 9volt/
thanks alot for this cool project. Im building it for my girlfriend... am i cool or what :P

Re: Small Tesla Coil using disposable camera transformers
flannelhead, Sat Aug 06 2011, 08:31PM

Actually I think input voltage is the most important limiting factor. Once I tried running a flash board transformer at 9v. The transistor died, but an eyeblink before there were sparks in the transformer. I don't believe the transformer would work at more than ~3V primary voltage, because otherwise the secondary voltage will be too high and insulation will fail.

Sounds good! Good luck with the project.

Re: Small Tesla Coil using disposable camera transformers
Chip Fixes, Sat Aug 06 2011, 11:40PM

What a great idea! Christmas presents anyone?

Re: Small Tesla Coil using disposable camera transformers
jnbrex, Fri Aug 12 2011, 01:33PM

Can someone post a link to the tutorial for this? I can't find it.

Re: Small Tesla Coil using disposable camera transformers
H8erade, Fri Aug 12 2011, 03:27PM

Here you go:

Re: Small Tesla Coil using disposable camera transformers
Tetris, Sun Aug 21 2011, 07:44PM

I need one. hm. touch the spark.... NO LICK IT! XD. I dare you to touch the discharge with your tongue. I need more flash boards. I put about 30 of them in a box and put them in the attc, labeled by my dad as "Do not open until after 2021." In ten years I will be away from flash boards. But they are still pretty awesome. I need to know how to build this coily!

Re: Small Tesla Coil using disposable camera transformers
HDF49, Fri Oct 28 2011, 12:20AM

Here's my take on one of these:


Those are two 2 pence pieces for the topload, more info http://4hv.org/e107_plugins/forum/forum_viewtopic.php?127097