DC fed circuit for fluorescent lamps - has transistor inverter and oscillation circuit with reduced power during start by switching relay for lamp electrodes preheating

摘要

The D.C. supply source, e.g. a motor vehicle accumulator battery, uses an interconnected transistor inverter with two transistors for the lamp feed. The heating current through the electrode circuit is used for the control and maintenance of the inverter operation. The electrode circuit forms an oscillation circuit and consists of the series connected electrodes, a capacitor, a feed transformer secondary, and a control transformer primary. The control transformer secondary regulates the inverter transistors. In order to provide preheatings of the lamp electrodes, the oscillation circuit quality is temporarily reduced during switching on by a suitable load and a switching relay. The load, disconnectable by the relay, is preferably coupled to the control transformer, the relay operating with a delay.