Picture of Super Simple ignition coil drivers
ignition coil circuit.gif

Remove these adsRemove these ads by Signing Up

Step 1: Lets start with the bacics

Picture of lets start with the bacics

OK, an ignition coil (or spark coil) is a type of induction coil similar to a Tesla coil . it's used in combustion engines. and produces up to 50,000 volts (a 2-4CM spark) at a lethal current of 25ma.

to power it, you need a square wave. you cant use standard AC because the coil WILL EXPLODE!

Step 2: How my schematic works.

Picture of how my schematic works.

This is how my schematic works: heres is a schematic that shows what the capacitor does. This the first schematic. It is a good driver for making big, hot sparks (not to be confused with arcs).

Step 3: My schematic (cheap and easy)

Picture of My schematic (cheap and easy)
Video 2 0 00 14-19.jpg
Video 3 0 00 06-22.jpg

this is my schematic its easy, but it, with my power source, only makes about 20 KV (1 inch ark) at a low fixed freq. it's also noisy but still very cool. this makes VERY small streamers due to its frequency. and makes cool plasma globes out of light bulbs.

simple____ || ________________hard

$0.01__ || ___________________$50+

harmless shock ___ || __________________electrocution

Step 4: A super simple driver

this ridiculously simple driver with no doubt simple,and exceptionally cheap and can easily produce 40KV! there are a few disadvantages with it, its mains powered, making it dangerous, and the frequency is not adjustable.

simple_ || ___________________hard

$0.01_______ || ______________$50+

harmless shock _________________ || ____electrocution

(due to my laziness and super slow Internet, instead of pictures, here's another instructable showing how to build it. it will have the pictures and schematic in it)

Step 5: 555 timer driver

Picture of 555 timer driver

Another popular coil driver is the popular is this 555 timer driver.

it oscillates a transistor that drives the coil. its a little more costly and complicated but its overall relatively simple.

you can tune the output by the POTs. I haven't made the driver yet

simple____ || ________________hard

$0.01_____ || ________________$50+

harmless shock ____ || _________________electrocution

Step 6: Another 555 timer driver

Picture of another 555 timer driver

Here is another 555 timer driver. There are a few more components added and changed.
to me this is the most complicated circuitry I found.

simple_________________ | | ___hard

$0.01_____ || ________________$50+

harmless shock _______ || ______________electrocution

1-40 of 53Next »
apillai54 months ago

Hey Max , Do you remember me ? . Anyways I need your help . , i made this circuit and i have gotta problem , The 100ohm Resistor is getting Too hot and the 555 Timer got blown The Transistor is also getting too hot . The circuit works when i pulse the Dc , And I have not connected the capacitor as i do not know the value of the capacitor . SO PLEASE HELP ME MAXX

-max- (author)  apillai54 months ago

Pin 3 output is limited to I think about 200mA sink and drain. With 100 ohms, that means there has to be a potential difference of 20V across it. How much voltage are you feeding this circuit? The ne555 will not tolerate anything more than 16V, so do not feed it more than 12V w/o a voltage regulator.

To me that appears to be a 1/4 watt resistor, so you cannot dissipate more than 1.4W though it. Knowing that the 555 is capable of supplying enough current. 106mA @ 12V-1.4V(transistor's saturation voltage), totaling over 1.12W will completely fry that sucker, and since you only need a few mA's to saturate the transistor, you will need to choose a different, higher value resistor. Try a 220 ohm, or 470 ohm resistor. Keep incrementing up or down to find the best value.

Also, I did not build this circuit, I just put it all the circuits I found online into one place! Sorry if I can't help you more than that.

AdithyaP -max-4 months ago

I have mentioned in the photo of the circuit , 12V 2A wall adapter

-max- (author)  AdithyaP4 months ago

OK then, I can now see many, many problems. First and most importantly, do *not* omit the capacitor, it is necessary for the 555 to oscillate properly. Otherwise the stray capacitance between the pins will result in a very weak and unstable UHF oscillator that cannot drive the transistor or the coil. The value of it I believe is 0.1uF, but some experimentation will be needed to choose the exact value. (the output freq. should be between 40Hz-400Hz.) A "104" numbered ceramic capacitor should do the trick.

12V @ 2A is most likely not enough to get good performance. Once you get the circuit to function, you will probably be disappointed with the output. As the schematic you have shown calls for at least a 6A power supply. You can probably use an SLA battery for power. 12V high amperage power supplies are also really cheap, I modded an old Xbox power supply so that it can output 12V @ 12.6A. (Before the mod, even small over current transients would cause the thing to go into a fail-safe mode and shut down until power is removed. There was a custom chip that was responsible for that protection, and I simply shorted the optocoupler to the +5V rail though a small resistor, effectively bypassing the whole protection IC. Now there is no current limit or short-circuit protection)

Once you get the beefy power supply sorted, mount the transistor to a heat-sink or else it will overheat. TO-3 package style transistors are becoming more rare these days, so that is why an MJE3055 or TIP3055 may be a preferred choice. heat sinks for these are more common and readily available. Then if you still have issues with the 100ohm resistor, either try a higher value, or get a 3W 100 ohm resistor. Hope this helps.

AdithyaP -max-4 months ago

I am going to buy a 12V high amp adapter and try your recommendation :D
and i do have the heat-sink

-max- (author)  apillai54 months ago

If you still have problems, and you think you are killing the 3055, try a TVS diode across the collector and base that is reverse-biased (backwards so it does not normally conduct), and that it has a breakdown voltage of around 60-70V. A few zener diodes may also help, make sure they are beefy or paralleled up to handle the EMF transients well.

-max- (author)  apillai54 months ago

Your transistor should be mounted on a heatsink. This circuit is not the most efficient and as the transistor warms up, the worse it will perform and the less efficient it will become. That leads to thermal runaway (as it heats up, it makes more heats, causing it to heat up faster). The NE555 is not really the best chip to use with these types of circuits because it can be killed with strong EMF. Make sure use a separate power supply for it (from the main ignition coil power supply) or some beefy LC filtering and voltage regulators (with current limiting).

dillonxti1 year ago
relay circuit really works on msd blaster 2 coils
-max- (author)  dillonxti1 year ago
Great! Add some images, I'd love to see 'em!
dillonxti -max-11 months ago

here is my circuit

deej3972 years ago
Hey what type of power would you use for your step 5 schematic? Right now I'm trying to use a 12v lantern battery I got from radio shack but its not working. Also I'm on a breadboard just for testing purposes. I thought this could be done with 9v batteries so you'd think a 12v lantern battery would work but I'm having no such luck. Thank you

it is a 6v lantern battery not a 12v

-max- (author)  deej3972 years ago
I used both a 12V drill battery, 18 volt drill battery, a 12V PSU,

I have never heard of a 12V lantern battery, they are 6V. does it have any juice left? I had success with as little as 9V if I remember. (not the 9V battery, but a power supply.)

does the relay do anything? if it is buzzing, then change out your capacitor for a different one. small ceramic ones will not work.
deej397 -max-2 years ago
Well I'm using the ignition system on Step 5, I got it to work with a 12vdc wall outlet, but now I think maybe one of the components is fried, because it suddenly stopped working. I'm wondering what that component could be? I'm using a small .1uf ceramic capacitor and the 2N3055 Power Transistor. I don't think my 555 chip's fried because I switched it out and the same problem occurred. I tested the project on a breadboard and it worked, but it stopped working on the breadboard. I knew the project worked before so I soldered it up thinking it could be the breadboard making the connections not work 100%. Still doesn't work. Thanks for your reply!
-max- (author)  deej3972 years ago
I bet it is your 2N3055 transistor. not only is it hard to find a good one nowadays, but they also tend to burn up with inductive loads. The back EMF spikes fry them easy. You need a transistor that can handle lots of EMF (at least 10 times the voltage of the power supply), and thermal runaway.
deej397 -max-2 years ago
Thanks again for your reply, i did more testing in class today and figured out both my wall transformer (just a regular 12vdc plug with a transformer box as a plug) is fried, also the 555 chip. So i replaced the chip and replaced the plug with a digital power supply. I figured out when I adjust the 10k POTs, sometimes the volds would spike from 12 to 21 or 18, and the average current was 3 or 4 but that would sometimes go to 0 ( that might be because of the 555 chip was fried) So now my major consern is what is the proper power supply that is not a battery and wont fry? And kinda on the cheap but not cheap quality. Thanks for your time!
-max- (author)  deej3972 years ago
the best power supply to use would be one of the big clunky power supply’s that inside have a giant transformer, 4 diodes, and giant electrolytic capacitors.
deej397 -max-2 years ago
Thanks again for your reply, i did more testing in class today and figured out both my wall transformer (just a regular 12vdc plug with a transformer box as a plug) is fried, also the 555 chip. So i replaced the chip and replaced the plug with a digital power supply. I figured out when I adjust the 10k POTs, sometimes the volds would spike from 12 to 21 or 18, and the average current was 3 or 4 but that would sometimes go to 0 ( that might be because of the 555 chip was fried) So now my major consern is what is the proper power supply that is not a battery and wont fry? And kinda on the cheap but not cheap quality. Thanks for your time!
Can I use an IGBT instead of the 2n3055 transisitor. and will it improve the performance. also will the hv kickback kill it
HeatUp2 years ago
can you help a little bit abou the pic you uploaded at Aug 26, 2010. 6:06 that thing going from positive and negative terminals form relay is mthat capicator?
-max- (author)  HeatUp2 years ago
I don’t understand what you mean. are you referring to the schematic picture?

from the battery, the power enters the relay coil. here, the relay coil, capacitor and the normally open pins are in parallel. after the coil is magnetic flux built up, the the armature will short out the capacitor and let power to the coil.

the current then creates a magnetic flux inside the coil, where the outputs collects that energy and gives an output. then all the current travels back to ground (other battery terminal, usually negative side, but the polarity of the battery does not matter)
TeslaBoy2 years ago
It works but not as well as the relay driver since resonance can't occur in the primary circuit with out blowing the transistor up. To get a good spark you need primary resonance. Just like a good Tesla coil.
-max- (author)  TeslaBoy2 years ago
i didn't know that.

clearly the transistor in this circuit needs a snubber on here, maybe a .5uf capacitor across the primary and a diode in between one leg of the ignition coil, and the collector (or drain) and another HV zener diodes in series, one to prevent backwards flow into the transistor, and let the current go to ground.
TeslaBoy -max-2 years ago
That would work but would eliminate the resonance. In these digital circuits you just can't have any voltage or resonance in the primary. But at least that would allow you to keep this running.
-max- (author)  TeslaBoy2 years ago
the resonance will occur with the capacitor/primary tank circuit, and all the diodes will tame the current if it gets out of hand.

that what i think,anyway.
R.A.T.M2 years ago
couldnt you use this for a fly back
-max- (author)  R.A.T.M2 years ago
which circuit, some of them (like a modified version of the 555 driver) would drive flybacks, but some (like the relay-based ones) wont drive a flyback. flybacks require much higher switching speeds.
R.A.T.M -max-2 years ago
okay thanks man
I can't quite tell which direction the power flows, and where the battery would connect.....
-max- (author)  freenergyfuture3 years ago
looking at this schematic i see the coil connected backwards...

answering your question (i hope i understand what you mean) power (electrons) go from the negitive to positive. when building the circuit, one way perseve this on a breadboard is to split the schematic into 3 parts;

the timer circuit (555, resistors, capacitors, etc it flips on and off a current going to the base of the transistor), so build this and test it with a speaker or oscilloscope. 

the amp (the transistor that picks up the small signals from the timer and out comes large signals to the coil, [flipping on and off the power to the coil many times a second])

the coil ( that turning that pulsed DC into a high voltage)

oh, and the ground (3 or 4 lines at the bottom edge) is the - side on a battery and the +12V 6A is the + side of a battery.

so when building, make the first part, then second, then third. as you make it have parts go to the plus side and ground, (minus side)
bswt3 years ago
relay did not last that long
-max- (author)  bswt3 years ago
if you can pop it open, sand the crap off the contacts, and test. if it still doesn't work, your coil burnt up and you need a higher power relay.
Did you actually test the shock I've shocked myself with HV a lot more than I should have but I would never do it intentionally? Camera flash systems really hurt as well as HV capacitor discharge. My worst with ignition coils was a direct strike from this ignition coil driver.
-max- (author)  The MadScientist3 years ago
it doesn't look like it would hurt nearly as much as this page... the circuitry looks similar to page 5... just with a voltage regulator and a high voltage muffler.
anyways, no. i never even built this circuit, though others that did say it really hurt. and examining the circuitry, i don't blame them. also, just look at the second picture, to me that is a death spark!
Actually, that is not a high voltage muffler so much as it is a gate drive shaping circuit. It limits the current between the 555 and mosfet during turn-on which momentarily takes it into it's linear region. Then, it gives it a hard, quick turnoff, but still protects the 555 from mosfet failure by current limiting.
That does look pretty high Amp the flash circuit hurts enough.
Kirbsome!4 years ago
I've been looking for something like this, can the first driver use a 9v battery?
-max- (author)  Kirbsome!4 years ago
i tryed with a more powerful 9V driver recently (wall-wart) and it work! but with less epic sparks :( i found the 24V works the best but the relay will need to be modified with a bigger spring in it so it doesn't lock up.
-max- (author)  Kirbsome!4 years ago
i don't know for sure. i tried with my model, and it produced tearable results (400 volts the first second or so, then died out. but again the battery was probably half dead.

also,the circuit actes like a VCO (voltage controlled oscillator) more voltage, lower freq.
Kirbsome! -max-4 years ago
So, I need low voltage high amps?
1-40 of 53Next »