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Jacobs ladder with ignition coil? Answered

I got an ignition coil From a motorbike repair shop for free, I cant find a way to use this to Build a Jacobs ladder. I think it works as motorbikes have it for producing sparks that pass through air. Any ideas to help me in this build is appreciated. Should i use DC but i don't see two points for connecting the wires from a battery. the model no of the ignition coil is "Yamaha SAP-1737 " 



7 years ago

I can tell you how to hook it up to power, however this may still not work. apparently it may need a sine wave or square wave current. I don't know for sure but this may be done with the condenser, i don't really know what condensers have to do with coils, but most cars and bikes seem to have one. anyway, your negative is where you bolt it to the body/frame of vehicle, also the positive is that little tab/terminal you can clearly see in pics 1 & 2.


8 years ago

Do you know if that coil is used on a CDI ignition system or a standard "Kettering" system? 

I found a site that carries these coils, and the picture shows a coil with the same PN as yours:


Their picture shows a thick lead coming out (most likely the heavily insulated HV output) plus one red wire. It may use the frame or bracket as a common. I couldn't tell if there were other wires from the picture at the site.

At any rate, you'll need some way of driving the coil properly to generate a HV output of any kind.

If it is a standard coil you will need to have a circuit with a switch that lets current flow through the primary side, and then interrupt it to generate the HV output.  There are many circuit of that type on instructables and elsewhere.

As for using it to drive a Jacobs ladder, you will probably end up having to overdrive it at least somewhat to generate a hot enough spark.

The Skinnerz

8 years ago

Unless the bike it came off of has an unusual ignition system, you should be able to drop the coil straight in to any of the ingnition coil HV supplies listed down the side of this post. Once you have the HV supply built, there are a number of good instructables on building a jacobs ladder, as well as other interesting projects.

This is a single unit, and shows how to build the whole system, but can easily be modified to power other projects.

If this is your first High Voltage project, you should read up on how to safely work with HV before starting.

Good luck with the project.