I am using the IRFZ44N MOSFET for my slayer exciter Tesla coil. The primary has 3 turns and the secondary about 1000 turns. The high voltage output has no load connected, it's just dangling mid-air.
However, my mosfet doesn't blow when I disconnect the gate.
My input is 24 V at 2.5 A max.
This is my circuit
At first my circuit worked fine for a couple of months. Suddenly, every MOSFET I put in failed. I blew over 3 MOSFETs that way. When blown, all the pins of the MOSFET are shorted but there is no "magic smoke".
Can someone please tell me why the MOSFET started blowing up all of a sudden after working fine for so long?