Mini Spark Gap Tesla Coil

Step 4 Primary Coil

The Primary coil is the that goes around the outside of the secondary coil. I am using 10 FT 1/4 OD copper tubing made in a cone shape. Before I got the tubing I was using 12AWG solid copper wire wrapped around a 2.5 piece of PVC. If this is all that you can get then that will be fine. I find the arcs are bigger at the third or fourth turn of the primary coil. Its best to use alligator clips on the wires to adjust the turns. The primary coil will be hooked up at one side on the tank capacitor and to the other side of the spark gap.