| 摘要 |
An electronic ballast employs an electronic inverter which drives a main power transformer across the output of which terminations are connected for a plurality of fluorescent lamps. A high impedance capacitor is connected in parallel across at least one and less than all of the fluorescent lamps. An auxiliary transformer is interposed between the output of the main power transformer and the cathode elements of the fluorescent lamps. Upon start-up, the high impedance capacitor initially creates a bypass around lamps with which it is connected in parallel to thereby apply the entire high voltage output of the power transformer to start the remaining lamps. Once these lamps are started the voltage drop thereacross is reduced to allow the high voltage output to bypass the high impedance capacitor and start the lamps connected in parallel therewith. The auxiliary transformer provides good magnetic coupling and low voltage to the cathode elements of the fluorescent lamps. A separate feedback transformer smaller than the main power transformer operates the electronic inverter to avoid operation of the main power transformer at its saturation limits.
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