Fluorescent lamp starter for electronic ballast - uses pre-heating circuit with current limiting impedance and bimetallic strip switch

摘要

The filament pre-heater for fluorescent lamps supplied with a high frequency current has the cathode filaments (3,5) connected in series with the terminals of a high frequency electronic ballast (1). It is momentarily connected to a circuit comprising a condenser (6) in series with a gas-filled tube (7) containing a bimetallic switch. When the lamp is started the bimetallic switch (7) is closed, allowing current to flow through the filaments to provide preheating. The bimetallic switch opens after a short time, opening the filament heating circuit and reducing the energy consumption when the tube is running. An inductance may be used in place of the capacitor to limit the current drawn from the electronic ballast (1).