Ceska verze

SGTC III. - Middle Tesla coil

     Secondary is 25 cm long, 7.2 cm diameter, 0.3 mm wire (pipe length is 55cm, but I simply run out of the wire in the middle :)). The primary winding has 4 very thick copper wire turns. The primary diameter is 20cm. Capacitor consists of five 2.5n, a total of 12.5n rated at least 30kV (home-made, of course). Static spark gap is built into large bakelite box and covered with plexiglass. Distance between the electrodes is about 2 - 2.5 mm. Power is limited to a maximum of about 300W.
     Meanwhile, without much tuning I can get 13 cm streamers and 16cm arcs into grounded objects.

     !!! WARNING !!! Tesla coil is an extremely dangerous device! Its supply voltage is deadly! Without knowledge of the principles of working with high voltage, you can not construct it. Tesla coil causes a broadband radio frequency interference. Electromagnetic radiation can damage electronic devices or storage media. The spark gap produces ozone (O 3), nitrogen oxides and other toxic gases, they have to be ventilated! Spark gap emits UV radiation. Current at ignition discharge of up to several kiloampers. Capacitor can remain charged even after shutdown. The device is very noisy and can damage hearing. Everything you do at your own risk! For any injury or damage I do not take any responsibility.

The schematic of the spark gap Tesla coil.

The Tesla coil primary waveform (simplified).


Arc to a coin. Never try this at home.

Really don't try this!!!

Halogen heater 1000W working as the variator (current-dependent resistor). Is connected in series with the high voltage power supply. Under standard operating conditions it does not heat too much. In case of fault it would limit the current. The picture shows the heater connected directly to 230V mains.