| 摘要 |
To prevent excessive voltages from interfering with a switching transistor supplying a fluorescent tube circuit with alternating pulses from a d-c supply upon removal of the fluorescent tube from the tube transformer, a voltage detector is connected to the primary or input winding of the fluorescent tube transformer to determine occurrence of excessive voltages upon removal of the tube from the secondary, the sensed excessive voltage being applied to a switching circuit to remove the transformer from the supply. The system is particularly applicable to emergency supply connections in which the tubes are, normally, supplied from an alternating current network and from a transistor inverter and a battery under conditions of network power failures.
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