Easy DIY Mini Tesla Coil (Solid State Slayer Exciter Circuit)

Easy DIY Mini Tesla Coil (Solid State Slayer Exciter Circuit)

Here's a video of it lighting up a light bulb wirelessly in my hand:

The Slayer Exciter is basically a solid state Tesla coil. It’s a high frequency oscillator (or is it actually a type of resonant power supply or an RF oscillator) with a 2N2222a signal switching NPN transistor (or put a PNP in backwards?). 

You do NOT have to manually tune this circuit to a specific resonant frequency. It all just takes care of itself, unlike a regular Tesla Coil. There is a parasitic capacitance to ground as a feedback.

DC to the big (secondary) coil > DC to the Base of transistor, 
DC to the small (primary) coil > to the transistor to ground.

DC goes from the other end of the secondary coil > to the transistor to shut it off.

It does this very quickly at high frequency oscillating (alternating)back and forth…and thus DC current is transformed into AC current.

The Slayer Exciter Tesla coil will function without a top sphere (or torus disc), but the frequency will be much higher.  A lower frequency will reduce heat in your transistor-saving it from blowing up. The Slayer Exciter is sluggish at any rate, which will cause transistors to die as it slowly oscillates on and off…which is why it should have a large heat sink with thermal paste.

You can also double or triple up the transistor: just lay them on top of each other and tie each of the three legs together, but that seems dumb to me: just use a proper heat sink or do what I do and just fun it for less than 30 seconds! I got the TO-18 package version of the 2N2222a transistor which is metal, but round…so the heat sink isn’t as easy to scavenge: it needs to be a star shaped sink with a hole in the center: that’s where you put the transistor.

E= Emitter                  B= Base              C= Collector

Most people build these with an LED (wired backwards), or better yet a Schottky diode (also wired backwards?). The LED acts as a safety device for the transistor, so the transistor doesn’t go too negative voltage. I’m doing without it for now. I like to build things with the least amount of parts as possible. Also, like a gillion people have built these and I'm just having fun here. If it blows transistors, even with a heat sink then I'll add an LED or Schottky diode. It worked first try without heatsink or LED or Schottky diode or even a top collector disc or ball.

Sort of Unnecessary Math: but it lets me know about how many turns my coil has. I see a lot of these with about 100:1 turns, "about" 3 to 5 turns on the primary to "about" 300 turns on the secondary:

                                         Pi = 3.14159

                                                   D = 1.5"

Circumference   =      C = Pi  x  D
                                      C = 4.7"

Feet of wire x 12 = inches of wire.

             197’ x 12 = 2364 inches

2364 / circumference of paper tube   =   # of turns in the coil.

Inches of wire / Circumference = number of turns.

              2364  /    4.7          =   502 turns

The thicker wired "primary" coil of 3 to 5 turns has to be wound around in the opposite direction of the turns of the "secondary" coil!!!!

So I ended up with about 500 turns on primary and 5 turns on the secondary coil.

Building:

-24AWG thin enameled wire (enameled means coated with insulation on the outside); 197 feet. Make sure to scratch away the enameling on the last inch of both ends of this wire!!!!!!!

-Random scrap wire thicker than the 24AWG to make a few (5 turns) of primary coil.

-Paper towel cardboard tube.

-Scotch tape and/or electrical tape to make things easier..

-Stand made out of blue cap from a water bottle to hold tube up (not really necessary).

-2N2222A transitor (metal or plastic, whatever you can order or you can find).

-Heat sink & thermal paste for transistor (I didn't bother since I only run it for about 10 seconds).

-22K resistor.

-Either a 9v battery and connector wires; or about 5v from a DC power supply with wires.

-Knife or sand paper or file to scratch away the last inch of enamel from the thinner wire.

-Metal soup can lid or bottom of soda can cut into dished disc or doorknob or a ball wrapped with aluminum foil for the top collector (I didn't bother with a collector).

-Solder and soldering iron (although you could probably just twist the few components together).

-A small fluorescent light bulb to light up wirelessly in your hand.

You can see the little tab next to the E leg below:

Scrap both ends of thin wire to remove about an inch of enameling. Notice the blue bottled water cap I used as a base:

Red is positive, black is negative from my DC power supply at about 5vDC:

Most "enameled" wire is coated in thin plastic instead of enamal paint or anodizing. That fine. Go with what's cheap:

I use power supplies, not batteries, so I don't need a separate on/off switch. I also left the LED (or Schottky diode) out of this circuit for now. It's just a safety device. If you put an LED in the circuit it will light up when it's "saving" the circuit from going too negative...kinda neat.

So, that's my super simple setup. I gave it around 5vDC and it lighted the light bulb in my hand!