2.1 Tesla coil schematic

"Tesla coil schematic"

                                                          (_______) OT 
                   T1                RFC1                     |
                   ||(-----+--------******---+---------+      (
                   ||(     |                 |         |      (
       +---+       ||(     o                 |         |      (
   <---|   |------)||(     o SG1             |         |      (
       |   |      )||(     |                 o         | L1   (
120VAC |LF1|      )||(-----+                           |   )  (
       |   |      )||(     |                 o MG      +-->)  ( L2
   <---|   |------)||(     o                 |             )  (
       +---+       ||(     o SG2             |             )  (
       |           ||(     |         RFC2    |   |  | C1   )  (
       |           ||(-----+--------******---+---|  |------)  (
     --+--         |                             |  |         |
      ---        --+--                                      --+--
       -          ---                                        ---
                   -                                          -

LF1 is a commercial line filter wired in reverse. Input (120VAC) is connected to the "load" side and T1 is connected to the "line" side. The case is grounded to the normal electrical ground. This helps keep RF energy out of the house electrical system.

T1 is a shunted transformer. Neon sign transformers and oil burner ignition fit this description. The core is grounded to the dedicated RF ground.

SG1/SG2 are safety gaps to protect T1 from RF "kickbacks". They must fire occasionally for them to be effective. Their spacing is slightly wider than the main spark gap (MG).

RFC1/RFC2 are RF chokes. They should be in the vincinity of 5-10mH each. MG is the main spark gap. It should consist of multiple gaps made of a heavy material such as hard copper water pipe. The number of gaps required is determined by your power supply.

C1 is the high voltage, pulse discharge rated tank capacitor. It should be a good match with your transformer for best results.

L1 is the Tesla primary coil. It should be constructed of a heavy material. Soft copper tubing is typically used, however heavy litz wire or stranded wire without a twist in it can be used. It should have a large surface area to minimize the skin effect. It is typically around 10-15 turns and has an adjustable tap for tuning.

L2 is the Tesla secondary coil. It is normally around 500-1000 turns of enameled magnet wire closewound on a sealed PVC or low loss coil form.

OT is the ouput terminal. Toroid (torus shaped) terminals should be used, but a sphere will also work, but not as well.