Solid-State Tesla Coil
Pumping out 30,000V on a dining room table
The Idea
As often happens, I stumbled upon an interesting video:
I knew about Tesla coils, but had never seen one that could play music. I needed to know how it worked. The answer was to replace the traditional spark gap, which acts as a crude switch, with a transistor; this allowed me to switch the coil on and off at a rate modulated by an audio signal.
As an added bonus, this design allowed the device to be made considerably smaller: the solid-state driver converts a low-voltage DC input into high-frequency current in the primary winding, so the coil does not require the traditional high-voltage mains transformer and spark gap. I never felt compelled to build a large-scale Tesla coil, but a small tabletop-sized one would be fun to have.
The Tools
- IRFP460-based solid-state Tesla coil circuit
- 0.25 mm enamelled copper wire secondary coil
- 30 V / 8 A DC power supply
- 3ds Max
- Creality Ender-3
The Process
A (somewhat crazy) experimenter in Slovakia has documented his SSTC build (based upon an earlier design), and I used this proven design to build my own.
1. The Parts
The circuit is straightforward, but required a few components I did not have on hand.
For the secondary coil, I needed insulated copper wire with a diameter of 0.25mm:
For the high-voltage transistor, I needed an IRFP460:
Because of the novelty, I followed the original build and used a Russian high-voltage disc-style power capacitor:
I also used some high-voltage film capacitors:
In order to wind the secondary coil, I needed a 6.3 cm-diameter pipe at least 13.5 cm tall. I modeled a tube (with an extension) in 3ds Max and printed it out on an Ender-3:
Lastly, I needed a DC power supply capable of delivering up to 8 A at 30 V:
2. The Build
Since this build was thrown together with parts on hand, Manhattan-style construction seemed appropriate. I attached the transistor to a spare heatsink (with some thermal paste), and attached the potentiometer and knob to a scrap 3D-printed panel (leftover from a previous build).
Winding the secondary coil was tedious work, but was successful. A copper spike was added to the top of the coil to control where (and how) the arcing occurs:
The end result looked sketchy but worked well:
The Result
The tabletop Tesla coil is capable of putting out arcs a few cm long:
- TODO: modulate transistor with audio signal