Table Top Tesla Coil

Table Top Tesla Coil

This is my first Tesla Coil, and rather small too. I figured it was best to start small, before moving on to several 100W coils. The output from the coil isn’t too bad, but not good for much else than demonstrations (not impressing people).

This is the basic schematic of the Table Top Tesla Coil. It is a SGTC (Spark Gap Tesla Coil) and is based on Nikola Tesla’s work over 100 years ago. Basically the secondary and primary are tuned to the same frequency, determined by the LC oscillation that takes place between the 440pf cap and 10 turn primary, and 500 turn secondary and top load. A lot of math is used to get the right values, but I didn’t know that until I started writing this. I’ll include an Excel sheet with some calculators later when I do my 300W Tesla Coil project. When the 440pf capacitor is charged to the break down voltage of the spark gap, it fires and the 440pf cap and 10 turn primary oscillate until the spark gap extinguishes. Since the secondary side is tuned to the same frequency the voltage induced into it is magnified by the resonance effect, causing massive voltages to be created. I’m a mere hobbyist, so don’t take what I just said literally as it may be wrong. Experiment with different capacitor and primary values until the greatest output voltage is found. A good site full of Tesla Coil calculators is Deep Fried Neon.

The 5kV PSU

Getting 5kV in a small package is easiest done making it your self. Simply take a fair sized ferrite core put a 1mm air gap in the core, and wind a minimum of 150 turns for the secondary. Then wind 10 turns for the primary, and remove them until the driver starts heating. I used my Basic Flyback Driver to drive the homemade transformer. A common ATX PSU transformer can be used for the 5kV xfrmr. Start with the spark gap distance at 1mm. More power can be pumped from the Tesla Coil by running the 5kV PSU from higher voltages. Try the 555 flyback driver MKII.I.

Troubleshooting

If the gap is firing, bring a grounded object close to the topload and check for sparks, if so, tuning should yield better spark lengths. Play with spark gap spacing, primary turns and primary capacitance.

Pictures

The fluorescent light bulb was ungrounded and held in my hand, a grounded fluorescent light bulb is much brighter.