陶瓷(ceramic)骨架与空气芯最好。铁粉芯(powdered iron)也可,环形(toroidal cores)也不错,就是不能用铁氧体材料(ferrite)。
此前一页,原文这样写道:
ceramic coil forms can give excellent results, as can self-supporting air-wound coils (miniductor).
if you use a magnetic core, make it powdered iron, never ferrite, and support it stably. stable vfos have been made using toroidal cores, but again, ferrite must be avoided.