| 摘要 |
<p>Electronic ballast for gas discharge lamps, particularly fluorescent tubes, which supplies them with high frequency AC at proper voltage from a supply of DC, such as a battery, solar cell or rectifier adapted to be connected to a commercial source of AC of any voltage, frequency and phase. The ballast is adapted to be used in combination with electrical system, e.g., the electrical system of a building, with many electrical connecting means such as fixtures for holding the fluorescent tubes, commercial frequency distribution means for AC at voltage suitable for appliances, small motors, etc, and the high frequency AC distribution system connecting the source of DC to one or more ballasts to supply the tubes to be used in the fixtures. The ballast includes inverting means (40) comprising a symmetrical class B, push-pull, current limited, dual feedback oscillator and preferably also not only a high frequency transformer (54) to deliver the output of the oscillator to the building wiring system but also a further transformer, e.g., an autotransformer (130), having its primary winding placed across the terminals of a lamp (132) and having at least one secondary winding for supplying heating current for the filaments (134, 136) of the fluorescent tubes. </p> |
