| 摘要 |
An emergency lighting system induces an AC current in a toroidal coil encircling a non-shielded electrical element of a power circuit, The AC current is rectified to DC and delivered to a rechargeable standby battery. The battery provides a first input to a NAND gate, and a proximity transducer provides a second input to the NAND gate. When the power circuit is energized from the power grid, both inputs to the NAND gate are high and the output is low. When no current is sensed by the transducer one of the input NAND gates is low so that the NAND gate output is high thereby delivering an illumination current to an emergency lighting LED either directly or through a boost amplifier.
|
