EDN (6 Nov 1997), Spice simulates a fluorescent lamp, Christophe Basso, On Semiconductor
A hot-cathode fluorescent lamp (HCFL) contains a gaseous mixture that flows between two tungsten electrodes, or filaments. In domestic applications, the mixture comprises mercury vapor and a small quantity of inert gas (krypton or argon). The inert gas vaporizes the mercury during turn-on. To lengthen the filament's lifetime, a preheating period brings the electrodes to a high-enough temperature before avalanche occurs. The warm-up is easy to effect by supplying the filaments with ac or dc during the first few hundred milliseconds. During this emissive period, the filaments increase the electron population in the tube and consequently reduce the avalanche potential, thereby resulting in a lower striking voltage for the lamp. Once struck, the lamp maintains a quasiconstant voltage, or "arc voltage," across its terminals. A practical value for the cold-striking voltage for a 5-ft lamp is approximately 1 kV, with a corresponding arc voltage of approximately 110V rms. A Spice technique offers an easy way to model an HCFL.