Simple SSTC


Introduction: Simple SSTC

This is a simple solid state Tesla coil with one MOSFET

Step 1: What You Will Need

IRF 540 MOSFET (other similar mosfets will work IRF 510, 630)


50 Ω resistor

1 kΩ pot

1 μF capacitor

Cardboard, glass or bakelite tube

Step 2: Operation

The secondary coil gest warm or hot, use cardboard, bakelite or glass tube. The secondary is made of magnet wire 200 - 400 turns, 0.1 - 0.2mm thickness. The coil dimensions are not critical (30 - 40 mm diameter)

The primary is only 1 turn, 4-5mm bigger in diameter than secondary, 1mm magnet wire, placed at the bottom of the secondary.

Turn the 1k pot when the spark discharge appears on the top of the secondary. At best adjustment the spark is longest and the mosfet gets warm slowly. If it don't oscillate, change the connections of the primary!

Resonant frequency depends on secondary coil dimensions and number of turns. It's between 2 and 10 MHz.

If you operate this tesla coil at higher performance (40-50W) the mosfet gets hot, it requires large heatsink.

Placing a top capacitance to the secondary, the spark gets longer, and the mosfet will be cooler.

The spark produces ozone!

Step 3: Video



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43 Discussions


9 days ago

Could I use a 470 ohm resistor and a 10k ohm potentiometer?

You copied keystone science

Can i use 40N60FL and split the schematic? Like i make powering of primary with transisor on rectified 220v (with current limiting,with fuse), and use 12-19 v powering to drive the gate?

so cool, but you should use mosfet z44, the lighting is bigger

2 replies

Yes, but I have only this type of mosfet, and unfortunately I have no stronger power supply.

Can i use resistor like 250Ohm and 10W to decreace gate voltage?

Hey can i use a 2.2uF capacitor instead of 1uF?

1 reply

I always wanted to make a Tesla coil, but the ones I found looked pretty much too big. This seems to be a nice one. What's the wattage of the 50 Ohm resistor?

11 replies

How to protect the gate from 40v 0.5A because irf540 is only 20 gate voltage

Adjust the pot between gate and source to minimum (between gate and 50 ohm to maximum) and increase it slowly when a small plasma flame appears. That's the correct adjustment. With a large heatsink, during adjustment, I did not burn the mosfet.

The resistor is 2W, my device is running at 40V, 0.5A = 20W. The resistor doesn't get hot, I don't know what about higher performance.

Can I use a 51 ohm resistor instead of a 50 ohm resistor?

For sure. General resistors have an accuracy of 10%. 50% +- 10% gives a range of 45 Ohm to 55 Ohm. So even with a 5% accuracy you would be on the safe side.

Thanks for the fast reply!

I am planning to build this little tesla coil.

I have a few more questions:

How did you make the 40v power supply?

How many secondary windings did you use?

And in which direction do I need to wind the secondary coil?

Buy a step up boost regulator, or you can just make one for fun. If you dont know what a boost converter is, its basically takes low voltages and converts to a higher voltages. search them up.

How many secondary windings did you use and in which direction do I need to wind it?

Hi! Sorry, I know I reply late, but I was busy recently. 51 ohm will work well. Doesn't matter what is the direction of the secondary, if there is no oscillation, change the polarity of the primary. It's easier. First, try with 200-300 turns on a cardboard tube. Power supplies between 20 and 40V will work. My power supply is a small, 20W transformer from a satellite receiver, a rectifier bridge, and a filter capacitor. Good luck!

I only have a cardboard tube with a diameter of 5.5cm, will it work?

Yes, diameter is not critical, but you can use glass, bakelite tube etc. any other material that not melt because secondary coil gets very warm, almost hot during operation.