For this TC I made a new secondary with a diameter of 108 mm and a length of 375 mm, wire diameter is 0.2 mm. Resonance without terminating capacity is 204kHz, resonance with 6 "toroids" made of cans is 134kHz. Resistance of the wire is about 300R. Excitation is again with the circuit IR2153, interrupter is UC3843 (low voltage equivalent of the popular UC3842). Mosfets are STW29NK50ZD with parameters: 500V, 29A, 95mR, 350W, 6450pF, 45/45/133/25ns, TO247. So far I have not destroyed them. They have G-S zener diodes built-in, so no need for external ones, but I had ones in the circuit, so I left them there :). In 100Hz (full wave) operation this tesla coil draws about 1000W, with DC operation over 1600W. After connecting interrupter the power depends on the set duty cycle. Discharges into the are 25cm, into a grounded electrode 30cm long.