Tiny Tess – Small Classic Tesla coil

Tiny Tess

Tiny Tess is a very small teslacoil, designed to run from a 12v supply and to be as compact as possible,

Primary: 5T 1mm emameled copper wire.
Secondary: 3" tall 0.5" diameter, 500T on a 5ml syringe former. wound with 0.125mm Wire.
Primary Capacitor: 1nF.
Spark Gap: Miniture RQ gap from 4mm Dia Cooper tube.

At present Tiny Tess is running from a 5-0-5 kv 20khz electronic supply, and its giving about 1" arcs to air .

Picture shown with a 'D' Cell to give an idea of size.


First light, running from 12V, Primary cap charging to around 5KV

Its got streamers, its arcing, and it lights a flourescent tube , it must be a teslacoil!!

12v - 5Kv PSU Circuit Diag Here
Psu gives me 5Kv at 5mA, (So Far.) The whole circuit is in bits, on vero etc and none of the Mosfets have heatsinks (yet).

Transformer is 4 turns x 1mm and 2000(ish) turns 0.125mm on an ETD49 core.

Transformer driver borrowed from Steve Connors IGBT driver and posts on a full bridge implementation (see Flyback Driver)

TC resonates at around 3Mhz.

Improvments to be looked at:-
Less lossy retification to TC.
Fine tune TC.
RF isolation from PSU.
Rewind secondary coil with 46 SWG wire (0.04mm approx).

More Info to come.......

In an effort to get better quenching I tried a rotary, 13mm in Diameter, Driven from a small 6x6x16 mm motor.

On First trial at full RPM, I had running sparks up the coil, a good indication of more power, but bad tuneing.

Corrected tuning, Found it worked better without Rotary. 🙁

Maybe running rotary much faster will help. Ill use RQ gap for teting until I'm happy with PSU. Im still getting the HV rectifier diodes getting hot.

Added 0.47nF to primary Cap, and reduced the primary turns to 2.5 Turns

Changed the top load to a aluminium door knob from Ikea (slowly becomming my No.1 topload supplier 🙂 )  Varnish removed and polished.

Rectifier diodes changed to 8kv 10mA ones and doubled up. They seam to be better as their not getting so hot.

Now getting 1"+ streamers from the topload and hot arcs to earth.

Click images for a larger pictures.


Picture of the whole project, before tidying up and boxing.

So Now I'll build another one, add the rotary, maybe DC resonant charging.