Supply circuit for fluorescent lamp - draws low current from 12 volt battery to drive transformer-coupled oscillator

摘要

A l.v. source, e.g. a 12 volt battery (1), is connected to a 25 kHz oscillator, transformer-coupled to the fluorescent lamp. The d.c. supply is connected to a current-sensing resistor in series with a switching transistor and the prim. winding of the transformer. The sec. winding is connected directly to the lamp. - One end of the transformer tertiary winding is fed back, via a resistor and capacitor in parallel, to the base of the switching transistor; the other end of the winding being connected via a resistor to earth. A circuit consisting of another transistor, two diodes and a capacitor stabilises the oscillator frequency and limits the peak currents in the oscillator.(0/1)