HF full bridge generator for fluorescent lamp - has two ring core transmitters with windings where drive of each transistor base is associated with ring core

摘要

The HF transformer is automatically controlled as a full-bridge HF stage over connected loads e.g. lamps (47,49,96,99). The transformer contains two ring core transmitters with windings (55-59, 62-66), where each transistor-base drive is associated with a ring core. The ring cores of a pair of transistors (18,19) and the ring cores of a second pair of transistors (20,21) have a common primary winding with two mutually insulated, parallel running windings. The parallel running windings are unsymmetrical with one having a smaller number of turns. The secondary winding has a smaller number of turns than the smallest primary winding. ADVANTAGE - Operation of fluorescent lamps in range 100 to 130 Volts, mains voltage in Japan and USA respectively, can occur without voltage doubling.