lämmitysjännitteen
Lämmitinjännite, sometimes referred to as filament voltage, is the voltage applied to the filament (or cathode) of certain vacuum tubes, most notably vacuum fluorescent displays (VFDs) and older cathode ray tubes (CRTs). The purpose of this voltage is to heat the filament to a temperature sufficient for thermionic emission. Thermionic emission is the process where electrons are released from a heated surface. In VFDs, these emitted electrons are then accelerated and strike a phosphor coating on the display, causing it to glow. In CRTs, the emitted electrons form a beam that is directed towards a phosphorescent screen.
The value of the lämmitysjännite varies depending on the specific tube or device. For VFDs, common filament