| 摘要 |
PROBLEM TO BE SOLVED: To provide an emergency lighting device in which welding or the like is unlikely to occur at relay contacts. SOLUTION: If a commercial dc power supply E is cut off, no current flows through a relay coil RyL, and relay contacts RyS1, RyS2, RyS3, RyS4 are connected to an inverter circuit 3. Even if a transistor Q4 is released from a reverse-biased state, the inverter circuit 3 is not oscillated until current stops flowing through the primary winding Tr31 of a transformer Tr3. When the relay contacts RyS1, RyS2, RyS3, RyS4 are to be switched at the detection of power outages by the relay coil RyL, arcs are not produced in the relay contacts RyS1, RyS2, RyS3, RyS4 and welding does not occur since no voltage is being applied from the inverter circuit 3. Current stops flowing through the primary winding Tr31 of the transformer Tr3, a light-emitting diode LED 1 is turned off, and a phototransistor PTr1 is turned off. The dc power of a battery B is supplied to the inverter circuit 3 to actuate the circuit to oscillate at high frequencies, thereby inducing a high-frequency alternating current in an output winding Tr22 and causing high-frequency lighting of a fluorescent lamp FL. |
