| 摘要 |
<p>SOLID-STATE DEVICE FOR LIGHTING FLUORESCENT TUBES IN EMERGENCY A device for lighting fluorescent lamps in emergency comprises a pushpull oscillator whose transistors act as an on-off switch to obtain a square wave a.c. voltage from a d.c. source. This a.c. square wave is transformed into various voltages by using a tapped secondary winding on the oscillator transformer. Two small sections of this secondary winding feed the filaments of the tube and a larger section sandwiched between the above two provides the operating voltage for igniting and maintaining the discharge in the fluorescent tube. The remaining portion of the secondary winding is capacitively connected to the centre of the primary winding which aids starting of the lamp. The d.c. source is charged by a regulated charger which maintains the battery fully charged (without overcharging) under normal power supply conditions. A control device substitutes the use of an electromagnetic or solid-state relay by keeping the oscillations damped whenever the normal power supply is not interrupted.</p> |
