This is my first Tesla Coil. I figured
it was best to start small, before moving on to several hundred Watt coils.
The output from the coil isn't too bad, but not good for much else
than demonstrations and displaying the concept.
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 designed to have the same resonant
frequency, determined by the inductor and capacitor. The primary
oscillation takes place between the 440pf cap and 10 turn primary.
The secondary oscillation is between the 500 turn secondary and top
load, which believe it or not has capacitance to ground. A lot of
math is used to get the right values, but I didn't know that until
I started writing this.
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 energy transfer
goes very easy. The voltage induced into the secondary side is
magnified by the series resonance effect, causing massive voltages to
be created. Since ground is the other part of the secondary circuit
it will arc out into the air in an attempt at completing the circuit.
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.
Parts used to create the Table top SGTC
The 5kV PSU
Getting 5kV in a small package is
easiest done making it yourself. Simply find a fair sized ferrite
core, put a 1mm air gap between the core halves, and wind a minimum
of 150 turns for the secondary. Then wind 10 turns for the primary.
Remove turns until the drive MOSFET starts heating. I used my Basic Flyback Driver
to drive the homemade flyback transformer. A common
ATX PSU transformer was used for the 5kV xfrmr.
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, and possibly streamers. Play with
spark gap spacing, primary turns and primary capacitance to tune the
Tesla coil perfectly.
Arc to a grounded screwdriver and ungrounded fluorescent light held in my bare hand. A grounded fluorescent light shines much brighter.
Disclaimer:
I do not take responsibility for any injury, death, hurt ego, or other
forms of personal damage which may result from recreating these
experiments. Projects are merely presented as a source of inspiration,
and should only be conducted by responsible individuals, or under the
supervision of responsible individuals. It is your own life, so proceed
at your own risk! All projects are for noncommercial use only.
This work is licensed under a
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
