feature Even filament is broken, the tube still works (constant luminance);Constant voltage for the filament, making tube life two times longer;Pre-heating start by IC VFC, reducing the tube darkening.Advanced APFC circuit, high power factor approaching 1, harmonic content meets 3C requirements. application car, metro, ship, machine tooled workshop, precision instrument room, communication control center, high-class office building and places need frequent change, etc.
